 Good afternoon and welcome to the eighth in the series of seminars looking at our future in space. My name is France Cordova. I'm NASA's Chief Scientist and I have the pleasure of introducing today's speakers. But first I want to ask you to mark your calendars for January 29th. Same room, same time. That will be to this year's administrator's series as the Super Bowl is to football. It'll be a wrap-up of what we've learned in a plan for the future. Where is NASA science headed? Mr. Golden himself will give that talk after a short video presentation which will be a montage of this whole year's series of seminars. Today's subject is the plasma universe. The NASA Science Council selected this topic because it embraced a lot of the sciences that NASA is interested in, especially the crossover between the traditional space sciences and the earth sciences. The figure that you will see on the screen illustrates just how embracing the plasma universe really is. This figure shows plasmas that can occur naturally or can be created in a laboratory. The plasmas are shown as a function of temperature and density. You can see that the disciplines of NASA embrace the universe of plasmas. From the pulsar magnetospheres in the relativistic plasma regime to the classical plasmas, the earth's magnetosphere, the solar corona, the solar wind, to quantum plasmas like white dwarfs. With us this afternoon are some of the leaders in the field who are responsible for identifying and explaining the rich collection of plasmas. Their behaviors and the processes that underlie these behaviors. They're going to describe how knowledge of these processes operate in all of the regimes that you see here and how those processes provide us with a quantitative understanding of the complex terrestrial environment as well as lead us to understand the origins of behaviors in the astrophysical environment. These plasma phenomena lead to fundamental scientific questions relating to the behavior of plasmas under extreme conditions, under conditions that are very much different that we observe here on earth. So we investigate these plasmas in the universe to lead us to a broader physical understanding of plasmas in general. And you're going to hear too about some of the applications of plasmas. To ground-based communications, protection of instruments in geosynchronous orbit and the safety of astronauts in orbit. So now I want to introduce the originator of this series, our NASA administrator, Mr. Dan Golden, who will make a few remarks on this subject. Thank you for coming. The series was scheduled during the government shutdown and it grieved us, but we had to cancel it and give everybody short notice for coming back the second time. So I'd like to thank everyone who has been flexible enough to come. We've discussed a whole variety of scientific subjects, and if you will, the subject could be the glue that ties it together. When we think of space, we think of planets, we think of suns, we think of small bodies, we think of galaxies. But in that, quote, empty space is a not-so-empty space. There are charged particles, there are gases, and there are things that are among the origins of the universe. So this is a very important subject, and it really began with Dr. James Allen, when he discovered those belts around Earth, the radiation belts. And it was just last Thursday that I was out of the Jet Propulsion Lab, and I was talking to the people assembled there, and I was pointing out, as had been pointed out to me by some of the scientists out there, that they have even more intense radiation belts at Jupiter, and they maximize right around EO, but we made that very critical maneuver to go into Jupiter. The magnetic field, I think, is 10 times that at Earth, and there's a copious quantity of charged particles there. So the radiation is very intense. So A, we'd like to understand it, and B, just to send future probes to Jupiter, we'd better understand it so we could design those probes. So I'm glad that France pointed out that there was a practical aspect and an intellectual aspect. So today, I look forward to hearing about the glue, and with that, I will get off and ask our first speaker to come up. So I have the great pleasure now of introducing Dr. James Spen Allen. The era of in situ exploration of space plasma began about 1946 using V2 rockets, and Dr. Van Allen's group of graduate students and himself at the University of Iowa was prominent in this venture. In fact, for two decades, from 1945 to 1965, this team pushed the boundaries of experimental technology in examining space plasmas. Dr. Van Allen had a very significant role in the international geophysical year of 1957-58, and this culminated with the launch of Explorer 1 in January of 1958. On it was a micrometeorite detector and cosmic ray experiment of Dr. Van Allen's group. With that data from this and also from Explorer 3, which was launched just three months later, this group put together the picture that we now have of the local space environment. They made the first space science-age scientific discovery, and that was of these donut-shaped regions of plasma, charged particle radiation trapped by the Earth's magnetic field. These belts of radiation now carry, of course, Dr. Van Allen's name. Dr. Van Allen has extended his studies from the Earth to the larger magnetospheres of the outer planets as an experimenter on the Pioneer spacecraft. His strong advocacy was critical for the success of the mission that we saw last week that Mr. Golden referred to, the Galileo mission. Dr. Van Allen is presently regent distinguished professor of physics at the University of Iowa. He's a member of the National Academy of Science and past president of the American Geophysical Union. It has awarded him several of its distinguished prizes, including the Fleming Prize and the Bowie Medal. In 1989, he was given a very singular award, the Crawford Prize of the Swedish Academy of Science. This prize, those of you who are familiar with it know that this is a great honor that it has bestowed in the fields for which the Nobel Prize is not awarded. But perhaps I think what Dr. Van Allen would say is that his greatest legacy is in the young people that he inspired and that he trained. These are the people who are today providing for the United States leadership in space physics. Dr. Van Allen. Well, I'd like to say that the warm weather in Washington is a pleasant surprise for me. Now, about 30 years ago, I gave a talk to the IEEE National Conference at the IEEE, the Institute of Electrical and Electronic Electrical Engineers. And there was one person in the front row who seemed a little restless during my talk. And as soon as I finished, he popped up and said, well, I listened very carefully to your description of how protons and electrons wander around in the Earth's magnetic field. But Dr., please tell me what a radiation belt's good for. And I, in my reply, I took that to be kind of a flip question, and I gave a correspondingly flip answer is, well, they helped me make a living. And I consider that a very worthy purpose. So today I thought I'd start with a, you might call the bottom line of my subject by discussing what are some of what I call significant practical applications of space physics. And see if I can get the right button here to start us off. Looks pretty good. All right, now here are some of the things that we really, I think, have a significant role in the area of practical engineering and operational applications of space physics. The first one is one on which I wrote a paper soon after we discovered the radiation belts having to do with what I call the radiation safe corridors for human spaceflight. And I'll show a little more detail on that later, but roughly speaking, you must stay below about 300 or 400 kilometers altitude in order to avoid a significant radiation of human crews in prolonged flight around the Earth. And of course, you can make a quick pass, as we did with the Apollo missions, with only a few hours exposure safely. But there is a very strictly forbidden region for spaceflight with anything resembling a present type of spacecraft. On the lower side, of course, is the air drag. So in effect, you're limited to a fairly narrow lamina of the atmosphere, which lies between the altitudes at which air drag is important and the altitudes at which excessive radiation exposure occurs. Also, there are very important radiation effects on solar panels, electronic equipment, optical surfaces, the exposed surfaces on optical equipment in Earth orbit. And these have the form of two major types. One is what we call signal event offsets, in which like a zero in a digital chain is changed to a one or vice versa. And that is equivalent to dialing a long distance number and making an error in one digit. And you end up by contacting someone in Kentucky instead of Florida. Now, the second one has to do with cumulative permanent damage, which is particularly relevant to solar panels and other types of electronic equipment as well. Now, the next point I want to mention was the consequences of high altitude nuclear bombers. And in the early, you know, mid-1958, we made the first major series of atomic bomb bursts, the so-called Argus tests. And with our little equipment that we made in our lab on Explorer 4, we made the primary observations of the effects of those high altitude bomb bursts. The biggest one that has ever been conducted, those are about 1.5 kiloton bursts. The biggest ones ever conducted was the Starfish, one called Starfish Burst from Johnston Atoll in 1962. And that was sort of a major geophysical event. So we've sort of calibrated the system so we know what you can expect from that range of nuclear bomb bursts as high altitude, either by an adversary or ones that we do ourselves. Now, there have been some notable examples of major magnetic storms, which have produced large-scale outages in electrical power grids. Some of you doubt this remember a few years ago. I don't remember the exact number, like five or seven years ago. If time frame, there was a major electrical outage in the whole New England area, encompassing New York City and major air population centers in the northeast due to a magnetic storm. And we don't pretend to know how to prevent those, but we do know how we were working on the possibility of predicting them so that electrical engineers can develop what you might call preventive protocols of what to do in case one is in the offing. It's something analogous to the Hurricane Prediction Center at Miami, which cannot prevent hurricanes but can give a certain warning to people who might be affected. This is a corresponding thing in the disruption of radio communications. This has to do with the effects on the ionosphere and especially at the lower frequencies. But even at the GPS frequency, which is in the L-band, there's also a significant error introduced in the GPS navigation fixes. And as Mr. Golden just mentioned, it has to do with engineering design of interplanetary and planetary missions. Specific examples are the design of the Encounter of Ulysses several years ago, the European spacecraft, and the recent encounter of Galileo, that the mission was conditioned on a tolerable radiation dosage to the equipment. And that's based on the surveys we made of the Jupiter's magnetosphere, first of all, with pioneers 1011 and with Voyagers 1 and 2. And Ulysses also contributed to that. And finally, I didn't remember this until last night. I should mention spacecraft charging, which is a plasma physical effect, which can have significant effects on communication satellites by charging up insulated surfaces and breakdowns of insulation. Now the sun is the big boy in this whole system. And I won't dwell on this slide much to say that, of course, the gravitational field of the sun is fundamental to the orbit of the Earth and all the planets. That's probably the first thing one should mention. Secondly, our electromagnetic radiations, ranging from radio all the way through to gamma ray radiations. Each one of these has its special features and special influence on the Earth. And of course, the most important one is obviously the visible infrared invisible, which keeps the Earth warm, and is our major source of life, of course, the support life on Earth. In addition, and less well known, are these what we call corpuscular radiations, which are distinguished from the electromagnetic ones by the fact that they're composed of particles or corpuscles. The solar wind, which is a plasma hot ionized gas, energetic particles, neutrons and neutrinos, in sort of descending order of importance in my subject here. Now the next view graph tries to respond to the question if you sort of meet an old friend on the street and he says, I wanted a space physics. That's what I'm trying to answer here. And it encompasses the vast variety of phenomena resulting from interactions. And I do want to emphasize the word interactions among the following classes of particles and fields, and sometimes called particles and fields physics. First of all, electrically charged particles, both electrons and ionized atoms. And they're interaction with magnetic fields, electric fields, electrical currents. And they produce electrical fields and they produce magnetic currents. So there's a two-way interaction. Electrostatic, a great variety of electrostatic waves occur in ionized gases and electromagnetic waves. And finally, they're interactions with dust and solid bodies, which plays a role in planetary magnetospheres, most notably that of Saturn. Now I have what I call a kind of a hierarchy of charged particles in space physics. And these read from the top down in order of energy and also in the inverse order of density or number density. First, we have what we call galactic cosmic rays. Those are, perhaps, the most ancient member of this family in a way. But they're single travelers. The average distance between two cosmic rays and as they come in toward the Earth is about 30 meters or more. So they have absolutely no interaction with each other and are, however, influenced by the magnetic field, by magnetic fields especially. They're the so-called anomalous cosmic rays, which are apparently originated within the solar system and become the kind of the low energy end of the spectrum of the galactic cosmic rays. They're radiation-built particles, which in ranking here, according to energy, come next. Which I'll say more about shortly, are solar energetic particles. Those have an energy far greater than the particles in the solar wind and are sporadic and in the order of MEV energies. And they're locally accelerated particles, which is probably a pervasive effect throughout the universe, but is under direct observation by various people in the interplanetary medium and at the bow shock of the Earth. Then there are rural particles, which are the traditional most famous manifestation of what we now call magnetospheric physics and plasmas and ionospheres. Some of my friends say that plasmas, that the 99-plus percent of all the matter in the universe is in the form of plasma. And of course, the obvious conclusion from that is that plasma physics is 99% more important than the sum of all other subjects. That the conclusion may be contestable, but the fact, I think, is pretty firm. Now, next, I wanted to give an answer to what I call the hierarchy of magnetic fields that corresponds sort of in diminishing, ordered with the one I had for the particles. And in pulsars, we have estimated magnetic fields of the order of 10 to the 12th power gauss. That's a million, million, million gauss at the Sun. They range in the order of 10 to the three gauss, although the so-called general magnetic field of the Sun is more like a few gauss. These are in sunspots and other active regions. In the case of the planets, the surface magnetic field in the planets is less than or about one gauss. In the interplanetary medium, it's of the order of 10 to the minus four gauss or less. And the interstellar medium is estimated to be about 10 to the minus six gauss. So that reads an enormous range of magnetic fields. On the previous sheet, the energies range from 10 to the 14th electron volts down to fractions of an electron volt. On this page, they range over a factor of 10 to the 12 down to 10 to the minus six. 18 orders of magnitude variation. Now, I have a few slides to give a little more substantive detail of these remarks. Dr. Cordova mentioned the fact that we'd explore. This is a very old slide. I may say this was a, this shows the fundamental discovery data from Explorer 1, which we discovered the existence of radiation belts. And there are three sets of curves here. This is a plot of the logarithm of the counting rate of our detector as a function of altitude. Now, the left-hand pair of curves was taken over the eastern South America. All three curves refer roughly to the geomagnetic equator of the Earth. The left-hand pair of curves was over stations in eastern South America. The central set of curves was over the west coast of the United States. And the right-hand curve was from over in Japan, the longitude of Japan and Korea. One of the most important things we first noted here, and as obvious here, is that the radiation belts come as much closer to the Earth over Brazil, near Brazil. That's the left curve. That begins at about 400 kilometers altitude, as we first encounter it. Over Japan, it's about, I think it's around 1400, I think. The difference between those two is 900 kilometers, which is exactly the well-known value for the eccentricity of the magnetic center of the Earth, which is 450 kilometers. That's been known for many years before. In fact, it was known for many years that there was a so-called South Atlantic anomaly, sort of a weak spot in the magnetic field. And these results are a graphic confirmation of that. And I just thought I'd show you the so-called South Atlantic anomaly. This is also a very old slide. Showing that patch off the coast, we call it originally, I think, the Brazilian anomaly. It's now generally called the SAA or South America, South Atlantic anomaly. And that shows the patch to which is the dangerous region for radiation exposure. And I've drawn in at least two orbits there, the ground trace of two low inclination orbits, one of which misses it all together. Of course, the other cuts right through the center, those are just exemplary possibilities. And here, that other was at 500 kilometers. This shows how that region grows as you go up an altitude. And this is the 1,000 kilometer cut showing the hot spot, the ready spot, and shows again how it becomes more and more difficult to escape. And all of that is very well covered in engineering manuals, which have been models, which have been developed by Jim Veddy and his colleagues that got it over the years and are standard for engineering purposes. And here shows one of our early results in which we first found that there are two major radiation belts around the Earth, the inner one which I've just been discussing and then an outer, much more distant one. And in the center of that inner radiation belt, an astronaut in a shuttle cabin would receive a fatal dose in about three days, if in a present type of shuttle cabin, about three days if orbiting continuously in the equator at the center of that zone. So this is not only dangerous, it is potentially fatal. Here shows how the magnetosphere of the Earth looks on a much more expanded scale in which now the radiation belts are just in the inner pocket there in the center. This shows the long and downstream wake behind the Earth, which we know extends for several million kilometers behind the Earth. And here is a slide, this might be of interest to Dr. Blanchard as well. This here, I plot the logarithm of the magnetic moment of the planet. As you know, we've investigated all seven or seven of the eight other planets. In other words, we've investigated a total of eight and out of the total of nine known planets. And a succession of missions. It's been a beginning in 1962 with our first mission to Venus. And we now have measured the magnetic moments of all of those bodies. And I plot here the logarithm of the magnetic moment as a function of the logarithm of the angular momentum. Now this is what sometimes called, with a sort of a sneer, it's called Bode's law of planetary magnetism, planetary magnetism. And that's intended as kind of an insult to people like me, and I don't mind that at all. But I just like to say that this is an empirical curve. And I plot all the planets on here. And I might say, and also include that box up there for pulsars, which seems to fall in the same general region. So regardless of the sort of the theoretical contempt for this relationship, I like it because it seems to be a very good empirical representation. As a matter of fact, I made a similar curve before Voyager two got to either Uranus or Neptune and I put a predicted value on there. I was fairly generous about it. I might say I put in plus, minus one order of magnitudes. Then one order of magnitude on this scale is not terribly conspicuous, I'd say. And Uranus and Neptune came right in the middle of my error bar. I think that's all the slides. Now I have two or three more view graphs to show. I must have hit the wrong button here. Let me try this one. That's supposed to be a buzzer or something. There we go. I don't know how do I kill the other one, I wonder. Okay. All right, now here's sort of looking sort of more toward the future. These are slides which are intended to give a kind of a basic orientation on the subject of planetary magnetospheres. And I list here the basic sources of energy. It's really astonishing how difficult it is to answer very simple questions. Like where does the energy come from? Where do the particles come from? Where do they go? Very simple things like that. And we're working our way through one at a time through the magnetospheres. The basic sources of energy for planetary magnetospheres are the kinetic energy of the flowing plasma constituting the solar wind. Or in case you're outside of the solar system and be the stellar wind. Secondly, the rotational energy of the planet. It's pretty tricky to figure out how you can convert or couple that rotational energy into the energization of charged particles. But many good people are working on that and they're making a lot of headway. And then the orbital energy of the satellites. Now where do the particles come from? These are potential sources of energetic particles. The solar wind itself, solar energetic particles which I mentioned earlier on. The primary cosmic rays which may, some of which may get captured into the magnetic field of the planet. There's secondary particles. We know this one as a very important source. Secondary particles from cosmic ray interactions in the planet's ionosphere, atmosphere, rings and satellites, very important source of the inter-radiation belt particle, the penetrating protons. Ionized gas from the planet's ionosphere. And gas sputtered from rings and satellites by a particle in proton bombardment. And gas emitted volcanically. The only example we have of that actually is Iowa and Jupiter, but that's a very important one. So that gas inflates the whole magnetosphere of Jupiter. And where do these things go? Okay, they go in various ways. First of all by radial diffusion once you have particles trapped in the magnetic field of the planet. And this tries to respond to the question of where they go and what it is you have to look into in order to understand that. That's the spirit of these various lists I'm making here is what are the things you need to inquire into in order to understand what's going on. And so this is kind of a shopping list as you might call it. First of all there's radial diffusion inward to the atmosphere and where they're lost in the atmosphere outward to space. There are various varieties of plasma instabilities and Dr. Kennel here is one of the world's experts on this subject, including pitch angle scattering by so-called Whistler mode waves and ion cyclotron mode waves. They're collisions with satellites in particulate matter and rings. That's very notably important at Saturn and also at Uranus and Neptune. It's a charge exchange with ambient gas and there are also gross perturbations of the weak outer magnetic field. Now I see I omitted a couple of slides and maybe if I can manage to get back to those I'd like to show I think my last two slides that they aren't lost by now. Just wanted to show one of Jupiter here if we can. Since it's a fairly live subject this week. Yeah, this is kind of a dramatic view of Jupiter's magnetosphere or the artist's conception of course, but we do have a lot of really good measurements on which this is based. And Pioneer 10 was the first mission to Jupiter and get a very good job of surveying the charge particle environment. One of the notable things about Jupiter is that because as we now know because of the plasma emitted by the volcanoes of Iowa there's an enormous amount of plasma which inflates the field. And that outward pressure sort of tends at the weakest point in the field which is at the equator tends to just stand the field out in a great tongue shaped region. And in addition to that there's also centrifugal force on the plasma. The combination of those two gives a great bent what we call magnetodesk there. And just to remind you here's the projected orbiting plan for Galileo which is now underway. So I think that completes. I'm probably over my time and apologize for that. Thank you. Thank you very much Dr. Van Allen. Our next speaker is Dr. Ian Axford. He is arguably New Zealand's most distinguished living scientist. He's one of those rare people who seems to be everywhere simultaneously. He's in international demand in forming science policy and program direction because of his exceptional contributions to research and administration. This afternoon he spent some time telling me about his recent attempts to help New Zealand reform the way that it does its science program and the management of the science. And it's really quite different than the way we do it in the United States. Dr. Axford's original training interestingly was in aeronautics in Manchester, England. He came to North America and applied the basic concepts of supersonic flows around blunt bodies to the problem of the flow of the solar wind around objects in the solar system starting with the Earth. He was the first person to speculate that a bow shock would be standing upstream of the Earth even though there was no known dissipation mechanism for plasma dissipation at that time. Dr. Axford was director of the Max Planck Institute for Aeronomy for more than two decades. He has authored more than 250 papers in space physics, cosmic ray propagation and acceleration. He's been president or vice president of many distinguished scientific societies past editor of the space physics part of the Journal of Geophysical Research and is the prestigious honor of being a foreign associate of our National Academy of Science. He's presently engaged, as I mentioned, in reshaping science in New Zealand and this year was named New Zealander of the Year. Dr. Axford. Thank you. It's a great pleasure to be here and especially to follow Dr. Van Allen with whom I worked many years ago when Voyager was called MJS and when Galileo was called Pioneer Jupiter Orbiter. We've come a long way since then. Let's get on to space. By our standard, space is empty or almost. The scales and the times involved are inhuman. If you stand in the right place, the right perspective, you can see that space is really filled with stuff and dominated by violence. There are very high temperatures quite commonly and some particles get accelerated to extremely high energies. These are the cosmic rays. The gas is usually ionized, a plasma and the magnetic field has an important role. Plasma physics is not just a matter for laboratories and the thermonuclear fusion program. It really began in our field in astrophysics and space physics. In fact, it began, I guess, with the observations of Gaseous Nebula and the sun's corona where people didn't understand the spectral lines they saw because they're not used to the temperatures that existed there. The pioneers of space research were concerned with the plasmas which were connected with the Polar Aurora with geomagnetic storms. They developed ideas about the solar copascular radiation or the solar wind, magnetic sphere, magnetic field reconnection and collisionless shocks. As the pioneers such as Dr. Van Allen were concerned with just about all of these problems. Alvein is a basis for his theories of such phenomena, invented particle drift concepts and the Alvein ways, which he got the Nobel Prize. The first radio scientist after Marconi concerned themselves with the nature of the ionosphere, a plasma, and developed the theory of wave propagation in this plasma and a Nobel Prize was given to Appleton for this. Our subject exploded, of course, there was the onset of the space age. This presented us with the Earth's radiation belts, which you've heard, the magnetosphere and the solar wind by 1960 and it's gone on from then with to become a major field of physics and astrophysics. You've learned to some of the subsequent development from Professor Van Allen and you'll hear of more extreme things from Professor Blanford, I'm sure, far beyond the solar system. I want to tell you something about winds, but not everything. Enough, I hope, to give you some idea of the subject and a feeling for its significance and importance, generally. Within the solar system, space is dominated by the solar wind. This was first invented to account for the behavior of comet tails, which look as if they're being blown away from the sun wherever they are, like cosmic windsocks at an airport. On the right there, you see some of the most recent results obtained from Ulysses. This is a plot, a radial plot, of solar wind speed against latitude of the spacecraft. And you can see that around the ecliptic plane, the solar wind speed black curve is fairly low, 400 kilometers per second. But in the higher latitude regions, above about 20 degrees, the speed is about 800 kilometers per second and it's actually lasted like that for years at a time. This trajectory took about four years and the high speed wind, 800 kilometers per second, persists for years and is homogeneous, more or less, during this whole period. It's a fundamental mode of the solar wind, which I think is only just becoming appreciated. I've plotted on top of this a picture of what the sun's magnetic field looks like at this time. And you can see that the high speed wind is actually coming out of the polar caps of the sun where we will find that there are polar coronal holes. I've tried to show this on the next view graph here. We were lucky with Ulysses after inordinate delays to eventually be launched so that we encountered the sun at sunspot minimum and saw this beautiful picture, which we got because as you can see on the top there, the solar coronal is quite different at sunspot minimum and at sunspot maximum. Sunspot maximum is a mess. We would have had a lot of trouble understanding what we saw and most of the wind at that time is the slow components. At sunspot maximum, the solar coronal is very beautifully ordered. We have very large coronal holes in the top and bottom, that is in the poles, and these emit high-speed winds. You can see this in the next picture from Yoko. This is taken at about the same time and the black areas on the top and bottom, partly obscured on the north side, are the coronal holes. These coronal holes show very little UV radiation, but in fact as much energy is coming out of those in the form of solar wind, as is coming out of radiation in the rest of the place. I forget how many megaton bombs per second, but it's a lot. The remarkable discovery has been made recently by the Spartan mission. They've been measuring the temperature of the ions above these coronal holes. We expected perhaps a million degrees, but you can see here two cases. The top one, this is a distribution function of Lyman Alpha, if you like. The proton temperature is determined by the width. The top one corresponds to a temperature of 4 million degrees, the bottom one to 5.2 million degrees, at distances of two to two and a half solar radii. This is quite remarkable. We had always thought of a million degrees, but suddenly we now know that the solar wind blows so fast because it gets so hot. Just as simple as that. Now, I seem to have got my view graphs out of order, but that's not surprising. Let's go on to the next development from this. There are probably winds. Is this the one you want? It's all right, it'll be okay. I'll readjust, recalibrate. You have Ulysses right behind you. It's okay. There are probably winds associated with most stars. In the case of the very hot young stars, they're extraordinarily strong and they may even cause a significant loss of mass to the star and they extend out into space to huge distances. If you look into this picture of 30 Doradis in the large melodic cloud, you can see the kind of mess that hot stars make in the medium. You have a mixture here of stellar winds blowing plasma away from that central region where you see all those hundred or so bright young stars concentrated together. Each has an enormous stellar wind. Some of them have blown up and made supernova and the rest of them are just shining ultraviolet light out of the whole region and causing it basically to tear itself apart. This is a good example of violence from the worldwide web. Now, in our vicinity around the sun, the interstellar medium is not quite so violent. It's a little warm, but it's still got a neutral component. Can I go back, please, to the previous one? I've lost it. Oh, dear. I've lost a view graph, the one that was on the left. Someone there that could rescue me? OK, thank you. This is what we see from Ulysses, fairly close to the sun, of the local interstellar medium. It's quite a remarkable thing. It's a little detective design just to measure neutral atoms coming and hitting a target. It just points all around the sky and makes a map. And so here's the celestial sphere. Along the middle of the picture is the ecliptic plane of the planets. The sun is a little yellow dot at the left is the position, and the earth is a little green dot next to that. Jupiter is the dot to the right in the ecliptic, and it's shining in neutral atoms, which this thing detects. The Milky Way is the loop, you see. And this is mostly ultraviolet, which the thing is sensitive to. But what's most interesting is the big blob in the middle. And that's interstellar neutral helium atoms coming into the solar system. These are interesting because they do have an effect on the heliosphere, which we'll talk about next. But before I do that, I would like to just point out the kind of solar wind measurement which is possible today with today's best instruments. These are spectra of the mass and charge distribution of ions in the solar wind. The top is in a high-speed stream, and the bottom is in a low-speed stream. It's a little hard for you to see quickly what's happening here. But both graphs are made with the same intensity for six times ionized oxygen. You can see the elements up and the charge horizontal. What one finds out from this is that high-speed solar wind comes from relatively cool regions and is normal composition, whereas the low-speed solar wind comes from a hotter plasma and has a rather peculiar composition enhanced in metals. On the left, you see another piece of violence from the World Wide Web, this time the Orion Nebula. I mentioned that the interstellar medium near us is generally rather quiet. But it may not have always been so. In fact, there's some evidence that a few tens of thousands of years ago, we were hit by a couple of shock waves from supernovae. This must happen fairly regularly. But the solar wind does carve out a special domain in the interstellar space. We call it the heliosphere. It envelops the entire planetary system. And here on the right are a couple of models which give you a feeling for this. The heliosphere is just, in fact, what you expect from a bullet in a supersonic wind, going back to my early education, as you pointed out. In the middle of the left-hand picture, you see the supersonic solar wind, the green spherical region, but it runs through a shock wave, the solar wind termination shock, and the gas or the solar wind that remains then just blown back to the right by the interstellar wind. On the right, you see the same picture, but this time it's neutral hydrogen atoms carried along in the wind. You can see that they are also caught up in the shock wave on the outside. They sort of form a wall of neutral hydrogen outside the heliosphere, which has been detected recently by Voyager and also by HST, Hubble Space Telescope, as I'll show you. The distance to that termination shock is about 100 AU. On the left, you can see how we know that. This is a discovery from Dr. Van Allen's group at Iowa. They found these two bursts of low-frequency radio emission on Voyager 1 and 2, and decided that they could only be caused by radiation coming from the far part of the heliosphere, the outermost reaches of the heliosphere. And they were able to connect these bursts with a couple of huge shock waves, which were emitted by the sun, seen at the Earth and by several spacecraft, and by plotting it outwards, they discovered the edge must be around 100 AU for the termination shock, and maybe 130 AU for the very edge of the heliosphere. A shock, by the way, is an abrupt jump to a hot, high-temperature dense plasma which propagates supersonicly. You're all familiar with the traffic shock when you see a lot of brake lights spreading backwards into the traffic when a red light goes on. Shocks usually are accompanied by heating, of one sort or the other, in the case of space, but also accompanied by the production of high-energy particles or cosmic rays. We believe that most cosmic rays are somehow produced by shocks in space somewhere, and that shock does seem to produce a special kind of cosmic ray, and if we can find it, we'll see cosmic ray acceleration in situ, we hope. Now, this brief tour of space has shown that from the sun's corona to the galact... Oh, sorry, I've missed a part. Oh, dear. There is more to this, I'm afraid. Stiller winds and so on supernova tend to make huge bubbles. They come together, make huge bubbles in the stellar space, and here's what the situation is near the Earth. You might be able to find the Earth down in the lower left corner of that funny-shaped volume there. We're sitting in the vicinity of two large bubbles, super bubbles, if you like. These are remnants of old supernova. What I've shown here is, though, something rather interesting. On the left of the Earth, we see the neutral hydrogen wall from the stellar gas. On the right, in some other place in the bubble, there's another neutral hydrogen wall associated with another star. Linsky from Boulder has discovered, using HST, that he can see both hydrogen walls and the hydrogen in between. So for the first time, we've discovered the heliosphere of a distant star, which is quite remarkable. These bubbles, though, exist throughout the interstellar space, and they must eventually escape from the galaxy, and the gas is very hot, filled with cosmic rays. And in fact, you don't only have a solar wind and a stellar wind, but we have a galactic wind, as I've shown you here. It looks just like the picture I've drawn of the solar wind. But I'm afraid there's more to it than that. Once you start opening your mind to these things, you can't stop. Clusters of galaxies do the same kind of thing. Here's a part of the Virgo cluster, which we're a distant member. This is the Coma cluster. You can see these little egg-shaped things that are galaxies surrounding a big central galaxy. There are hundreds of them in this case. In this case, we're only looking at the middle, and there are several thousand galaxies attached to that one. The clusters are interesting because they're full of very hot gas, 100 million degrees, which I think probably comes from the galaxies as galactic winds. Once it gets out there, it sits around, tries to cool, and if it has a chance, it does. The gas at 100 million degrees, they're cooled very slowly, but there's been a discovery in the last few months of gas in the Virgo cluster, our cluster, at only 500,000 degrees. Now if I can get this last view graph, you might see it, but it's not the right one. There's been a discovery from EUVE of a cloud of, there it is, of gas surrounding M87, that central galaxy, which has only a temperature of 500,000 degrees. It's cooling time as such, but the amount of mass that falls down is 1,000 solar masses per year, of that order, a tremendous amount. What it suggests to us is, in fact, clusters of galaxies have winds as well. The galaxies throw out gas, it's very hot, cosmic rays. It largely was to flow out of these clusters and to make a super cluster wind, as it were, with the termination shock, probably around the earth somewhere, but in the middle, the gas also falls inwards, onto the largest galaxy there, and just makes it grow and grow and grow. So it's eating up, in fact, its companions. So we can go from solar winds, right out to super cluster winds, if we like. But where do we go next then? This brief tour of space has shown that, from the sun's corona to the galactic cluster winds, the physics and the concepts are all pretty well the same. There's much to be learned from the solar system, where we can make very detailed in-situ measurements of what's going on. At the other end of the scale, we perhaps can only measure things remotely, and the measurements are less detailed. On the other hand, the variety and the sheer grandeur of the phenomena is sufficient to be very interesting indeed. Our customer, however, as the public, might well believe that it doesn't really need to purchase this kind of research, who it has a right to choose. And it went even today, a discoverer class mission fully costed with everything in, might cost up towards a quarter of a million dollars. I think our customer must believe that his investment, his and her investment, is a good one, that they've got value for money. Well, I think from my point of view, this might be the case for the solar wind anyway. There are a couple of interesting missions to do. The questions about in the solar wind are, where does it come from, and where is it going? Where is it going, is out into interstellar space. Did you see here the proposed mission to look at the outer heliosphere? It's already in place. It's Voyager, the Voyager interstellar medium. These spacecraft will survive until 2020 AD. They'll reach distances of 130 to 150 AU, and they'll almost certainly pass this shockwave and perhaps go into interstellar space within the next years. So that's worth doing, especially since it's there. Another interesting one is to go close to the sun to see where the solar wind comes from. And this has been proposed in terms of the solar probe mission, a close encounter with the sun, which has to be made during a period of sunspot minimum when there's a well-developed polar hole. And I think with such a mission, provided it's cheap and well-instrumented, we can do a lot towards discovering the origin of the solar wind. I won't discuss the right-hand thing at this point, but wrap up by saying that there's still a lot to be done, but it should be done in a measured and balanced and logical way that at minimum cost so that our public, our customers, really feel that they've got value for money. Thank you. Thank you very much, Dr. Axford. Dr. Roger Blanford will now take us out of the solar system as Dr. Axford began to do with his picture of the quasars, cluster of galaxies, rather. And Dr. Blanford's gonna take us to the universe at large and illustrate how what we've learned by studying the local environment of the sun and the planets of the solar system has helped us to understand the more bizarre denizens of the cosmos. Dr. Blanford was born in England and he did most of his schooling there, culminating in his research at the Institute of Astronomy in Cambridge, England with Dr. Martin Rees. And then he came to the States and was at the Princeton Institute of Advanced Study. And then in 1976, he went to Caltech as an assistant professor and only three years later he became a full professor and shortly thereafter, there Richard Chase Atollman Professor of Physics. He's been a visiting scientist at many prestigious institutions nationally and abroad. In 1982, he won the Warner Prize of the American Astronomical Society which is given to outstanding achievements for a young person in astronomy. He's given many distinguished lectures at universities including the marker lecture at Penn State University and the George Darwin lecture of the Royal Astronomical Society. He is a fellow of the Royal Society. He's produced a legacy that is very broad. He's consistently applied theory to many, many fields in astrophysics and his contributions especially to the theory of active galactic nuclei are enduring. Also significant is the potency of his work on cosmic ray acceleration. Dr. Blanford, welcome. Thank you very much, Hans and thank you very much to you and to Administrator Golden for your invitation to come here and share this podium with my colleague, Ian Axford and also Dr. Van Allen, one of my early scientific heroes. I'm going to tell you a little bit about the plasma universe and this side and as you heard, there's a lot of universe out there and a lot of it is plasma and from a physicist's point of view, of course one is looking at the interplay of ions and electrons and one is very much concerned about the rich variety of collective effects. There's an orchestra in fact that has its own conductor and this is a model for physicists for the types of many body behavior one sees in nuclear physics and liquids and so on. Now the advantage of studying plasmas in the cosmos is that one can observe them under very extreme physical conditions, conditions that one can in no way observe on Earth and these are these cosmic plasmas provide passive experiments whereby one can test fundamental theories of plasma physics. And so if we go just to see over here on the right hand view graph, we see the physical conditions as already mentioned in laboratory plasmas as typified by Tokamax and then in three particular cosmic plasma environments that I shall use as illustrations, supernova remnants, pulsar magnetospheres and jets and if we move straight on to the supernova remnants what one can see there, these are the remnants that are left behind from the explosions of massive stars either the metamorphosis of a star into a compact object a neutron star or a black hole or alternatively an explosion of an overloaded white dwarf that will leave behind essentially no remnant. Either way one has an explosion and this deposit I can't help, can't resist saying 10 to the 30 kilotons of energy into the interstellar medium and these explosions provide sites of heavy element production it's where we come from in some fundamental sense they provide the dispersal of this gas into the interstellar medium and they're a major energy source for the interstellar medium. From the point of view of a plasma physicist one of the major interests of the supernova remnants is that they are believed to be the site of most of the galactic cosmic rays that we see certainly up to energies of about 10 to the 14 or perhaps even 10 to the 15 electron volts and I can show you the one example of a supernova remnant this is one that was where the explosion was discovered by a famous astronomer, Tycho Brahe in the 16th century and if we have a look at that can we just go back to that one, sorry take that last viewer, thank you very much and this was one that in fact left no stellar remnant and what it produces now is an expanding shock front now we can go forward and this shock front thank you can go forwards now this, okay I think if you go forward on the right hand one please thank you, sorry center one, go forward on the center one that's right, thank you here we can see two versions of this actually what they've both been reversed unfortunately but one should be reversed and the other should not be on the right hand, on the your right hand side you'll see the radio image of that supernova remnant and on the left hand side you can see the image taken from the Rosat Observatory in fact the correct orientation and what I want you just to focus on is the top left hand corner of this image and if we now look at it again in the radio waves unfortunately that's been reversed too never mind, leave it, it's okay if we look there, all right you can see a very sharp feature on the outer side that is the outer shock front of this supernova remnant and that is where we believe the cosmic rays are accelerated by bouncing particles backwards and forwards across this shock front and we can get them from very low energies all the way up to energies of about 10 to the 14 or 10 to the 15 electron volts and this is a process that we can observe happening in a smaller scale inside the solar system and one that we would like to understand is what's happening in inter-cellar space so, next slide thank you very much so in terms of understanding the physics of cosmic ray acceleration there are many challenges to NASA and in some sense the general challenge to NASA is to be able to carry out the same sort of diagnostic measurements that we can carry out in the solar system to carry out those diagnostic measurements out in inter-stellar or space or beyond and so what we would like to do is use X-ray observations and radio observations to resolve and understand what is happening to the plasma and the magnetic field at a strong shock front caused by supernova remnant and one of the things that we observe there is a great big puzzle is those little lines that you see in the top left-hand corner are in fact the magnetic field direction they all go perpendicular to the shock front and I theory say it should go parallel to the shock front let us now so another challenge to NASA is to try to understand the composition of the so-called knee in the cosmic ray spectrum another way of putting this is to understand what is the maximum energy to which these supernova remnants are accelerating the cosmic rays that we see we think it's about 10 to the 14 electron volts or so and dramatic confirmation if you like of this idea has just come from a recent observation by the Japanese Asuka satellite and what you can see here are two grey belts of X-ray emission from another supernova remnant the remnant of an explosion that happened in AD 1006 and what one sees here are if you like the green region the grey regions excuse me are the sites of the emission by the highest energy cosmic rays of about 10 to the 14 electron volts and the red the remainder of the X-rays are those that are just radiated by hot plasma and seeing these high energy cosmic rays being accelerated and emitting directly by the shock front I think provides a nice dramatic confirmation of the theory of particle acceleration in plasmas and one way that we can advance this further is by understanding not just the electronic component of the cosmic rays of these energies but the elemental composition of the cosmic rays the how much iron and carbon and oxygen and so on there is and the way to do this is perhaps typified here by another part of Masha's mission which is to do space observations from balloon if you like and here sort of symbolize one hopes there's a real possibility of doing long duration balloon flights and Antarctica which would be one way along the road to understanding the composition of cosmic rays at the maximum energies that they can be accelerated by the by supernova remnants there are another very important type of physics experiment that one can do and this is to try and understand the behavior of cosmic plasma by analyzing the thermal component of the X-rays and here the key scientific question that is one that we're trying to answer in all manner of cosmic environments is how fast are electrons heated by hot irons because that very much controls their subsequent behavior it's we know how to calculate in one simple case but we do not have a good understanding of this process and theoretically in the only way we are going to understand it is by observations of objects like supernova remnants the next thank you very good now another challenge of one of the frontiers if you like is to understand cosmic rays of the very highest energy here's a view graph I like it's full of acronyms and I'm not going to tell you what any of them mean just to get my own back and so but what I want you to look is at the top right hand corner are the very highest energy cosmic rays and these are ones that have energies as high as 3 times 10 to the 20 electron volts and they presumably need about 3 times 10 to the 20 volts in some cosmic source to make them and probably on general grounds this requires a current if you think about simply electric engineering about 3 times 10 to the 18 amps I'm multiplying those two numbers together to give you a characteristic power of 10 to the 39 watts now this is a massive power as powerful as the most massive quasars which is telling you something about the sources but the trouble is they can't be any further away than relatively close by a few times further than the Virgo cluster because otherwise they wouldn't get here so we have a real puzzle we've got to do things very efficiently if you like faster, better, cheaper it's a slogan that applies to the acceleration of the highest energy cosmic rays as indeed it does to other types of other types of problem so there are many candidates for these the accelerators of these highest energy cosmic rays and I've listed some of them here some of them are really quite exotic there's a real discovery to be made here and one way to advance it is in fact a ground-based project the so-called OJ project which this is not NASA's job to collect these particles but what I really predict will be NASA's role in this business is to find the sites, to find the origin and I believe that NASA will actually make this discovery at some time in the future not with a special purpose satellite but one of the ones that it has on its manifest and I think that this is the way we'll find out where these highest energy cosmic rays are made so let me just go on now go on to my second type second example these are the Pulsar magnetospheres Pulsars as I'm sure you all know were a wonderful discovery of radio astronomy happened while I was a first year undergraduate and I can remember the excitement of the time it's been good for two Nobel prizes so far they are identified as spinning magnetized neutron stars and they have angular frequencies up to about 600 hertz for the musical amongst you that's top-y flat they're wonderful timekeepers we see magnetic fields as you've just heard up to a billion times that one sees in the laboratory and they have confirmed the general theory of relativity they're currently searching of course for gravitational radiation and there's all manner of uses for them as tools as cosmic probes they too are batteries like the Pulsars but they're not good enough for the highest energy cosmic rays there you see their meager voltages and amperages and they're also of course mostly seen as radio sources and here the power is very small just like the radio power of the sun is relatively small but the temperatures associated with this power are enormous prima facie evidence that one is looking at collective effects that are responsible for the radio emission and the short answer is we do not know the origin if you like of the radio emission from Pulsars and we would desperately like to understand that we have some idea of what is going on the temperatures are very high and so we get the plasma that we are looking at one of electrons and ions but almost certainly one of electrons and positrons so far we have about eight detections of Pulsars seen in the gamma ray part of the spectrum just let me show you here next view graph please I think ok that's great here's the gamma ray sky and Pulsars themselves as well as radiating the radio emission they also radiate gamma rays and we have seen them as I say about eight times so far and we would love to see them in many more environments what we need to know is essentially I think the next slide actually shows you a gamma ray detection here we see from the batsy gamma ray telescope one sees, you can see on the bottom frame here going through the pulse phase of a 0.2 second Pulsar a fifth of a second period Pulsar stacking up the data one can see gamma rays coming in a periodic manner from different parts of that pulse phase and you can see it if you like binned in the bottom there just from direct gamma ray observing just binning up with the pulse period and one if we move on and the challenge, the scientific challenge is to understand where these gamma rays come from and where the radio emission come from and it now looks like the gamma rays come from the outer magnetosphere this is a simulation done by my colleague Roger Romany and then that enables us to locate more precisely where the radio emission comes from which is terribly important in trying to understand the use of Pulsars as timekeepers and they are, I should remind you, as good timekeepers as anything we have on Earth there's a real competition if you like between Pulsar observers and people who make trapped iron clocks trying to understand who can make the better clocks or use the better clocks and so this is again a very useful thing to do and what is happening in space is that by observing the gamma rays one can observe, if you like, the particles and the plasma behaving individually, separately and observing at radio wavelengths one sees those same particles acting collectively it is if you like the gamma rays use the approach of Studs-Turkel radio astronomers use the approach of the Harris pole okay, so let's just go on to the challenges that's the next, there we go the positron electron plasma physics we love to understand these exotic relativistic plasmas and what we need is to have more examples and greater resolution on the ones we do have and that way you will be able to locate the sites of emission, understand the emission mechanism and in some sense understand the electrical engineering of the spinning magnetized neutron star and it has many puzzles that we actually cannot solve at the moment on the basis of present data let's just go on okay, now I want to go to my third example which are the jets associated with active galactic nuclei I too am going to show you M87 and here we see a giant galaxy this is somewhat coincidental a giant galaxy in the Virgo cluster relatively close by to us and what one sees here is on the right hand panel a jet of emission observed here in the optical in fact and one sees this is not in fact the best image of this but this is a nice long jet that squirts out the nucleus of the galaxy, the very center of the galaxy this phenomenon seeing jets squirting out of the centers of things is very common we know probably a thousand examples of this it's a trick that is performed by proto-stars it is performed by active galactic nuclei and it is performed by compact sources in our galaxies, it has also just been discovered and we see it here in the optical I haven't bothered to put in a shite I will review it in the radio because it looks almost identical we also observe it in the X-rays of course from space so again this is a wonderful discovery and the question is what is the origin of this jet how is it formed? now we know quite a lot about this particular object and what we see here is results of space telescope observations that have revealed a disk of gas that is orbiting in the center and they have confirmed a long-held suspicion that there is a central mass of a couple of billion solar masses that most of us would identify with a giant black hole what we can see is ok what we think we have here is a jet of fluid that is squirting out of the central region of the galaxy with a speed about the same as almost as fast as that of light and we actually see the features in that not their move at speeds comparable with the speed of light so that almost indicates that the escape velocity from the central object is about the same as that from a relatively deep potential well that is to say another more evidence that we are looking at a black hole now we can observe this jet out to a long way but we can also observe this just shows you the central gas disk and this is a way of measuring the central mass associated with the black hole let me just move on now this is another radio map made by a scientist at the Space Telescope Institute, John Veretta and this shows you how far in you can trace the radio jet and what is in fact tracing it in to distances of about 10 to the 15 meters about 300 times the radius of the black hole what we want to do is to see in as close as we can to the source of the jet to get the best evidence we can for the trick that nature is able to perform to be able to make these jets presumably by some sort of hydromagnetic flow and if we can understand the jet formation under these circumstances then we can probably understand it under a wider variety of circumstances in more distant cosmic objects so the challenge here is to understand how the jets are made and I think the way forward again for NASA to do this is undoubtedly through interferometry initially at infrared wavelengths but ultimately at optical wavelengths and this will enable us to see the site of the origin at these higher frequencies in much the same way as we've seen them here radio frequencies and I suspect the story will be much more much different and much more interesting in much the same way as if one looked at the sun firstly at radio wavelengths and then just studied it as a radio source and then subsequently studied it as an optical source and so what we would like to do is to repeat this observation if you like at optical and infrared wavelengths and that would give us the other side of the picture and would perhaps I hope let us understand what is the mechanism for the origin of these jets that are quite general now let me just finish okay if I just try and wrap up at this point and say what are the messages that I at least draw from these three examples of space plasmas beyond the solar system the first is if you like a an operational one and that is what is happening I think in a way that people never really quite suspected would happen is that space based observations and ground based observations are turning out to be remarkably complementary one does one type of observation in space and then compares it with the counterpart taken from the ground and the two together give you the picture and that is turning out in so many examples to be what actually happens the second is where I perhaps began by emphasizing is that astrophysical plasmas exist under conditions unattainable on Earth we have cosmic laboratories that enable us to understand basic physics in ways that we could never perform such experiments in our own laboratories and this way we can test fundamental plasma theory the way forward in many ways for NASA if it tries to achieve this goal of obtaining the same sort of diagnostics that we have for space plasmas is of course just pushing on the boundaries of resolution, spectroscopy and sensitivity and the discovery space is not at all explored I think as a theorist I can admit in public that the universe has been so much more ingenious and so much more imaginative than we have been and most of what we have discovered has basically been the unexpected I cannot believe that it will stop at this stage and I think that the voyage of discovery in terms of cosmic plasma physics will continue thank you very much indeed thank you very much Roger I'll take a seat over here I'd like to at this time invite Mr. Golden and our other speakers Drs. Van Allen and Axford to join Roger Blanford and myself up on the stage this is the time when after the talks when we open this discussion up to our audience and we invite you all to participate and to ask questions of any sort that is on your mind about this subject or its broader applications we'll start off just by maybe having a few remarks among the speaker a couple of questions of each other and then if you'll line up at either one of the microphones and I'll call on you when I see you standing there, thanks Mr. Golden would you like to start? Yes we've been trying to develop the overarching vision for NASA that integrates the fields we had for many years we've had these separate fields of endeavor and especially from the speech that Dr. Blanford had it looks like there's a real coming together of the type of facilities we ought to be putting up because NASA's about facilities and then the scientists use those facilities and we're trying to make our facilities more universal in nature we're looking at origins as a theme to understand the origins of galaxies and solar systems origins of planets and to understand the conditions under which life could exist or form we talked a lot about measurements in the infrared and optical we have a very vigorous plan going forward in optical and infrared we don't have as clear a vision of where we should go in the high energy measurements could you make some comments about that where you think we ought to go because beyond AXAP we don't have real planning and beyond a few of the other observatories we have up there we don't have any planning what would you like to see? I'd like you to see you go to harder X-ray energies AXAP as you know is a soft X-ray mission I think that to do imaging and there's some extensive spectroscopy in the band above say 5KV and as far as you can go is a wonderful opportunity as you know if we go up to the highest energies the EGRET detector on board BATSI gave you observations from 100 MeV to about 10 GeV and made wonderful discovery of the gamma ray counterparts of the jet that I showed in M87 the so-called gamma ray jets and has found about 40 of those and has also told us much of interest about gamma ray births and other types of cosmic objects and pulsars as well and I think that the technological capability exists to do much better and find so many more sources just as if you like to recapitulate the growth of X-ray astronomy looking at the lower energy region between say 10 KV and maybe 10 MeV again there are the instruments on the other instruments on BATSI have led the way and I think that is a frontier that will just be opened up in much the same way as one now has thousands of X-ray sources where once one only had half a dozen and I think that that is bound to make discoveries there let me just follow up with one other question we are looking at interferometry to get really high spatial resolution in the infrared do you see a real need for a very high spatial resolution in X-rays and would you ever conceive that we ought to put up an X-ray interferometer? gosh that would be a wonderful but quite a challenge I imagine that's what we're about let me back off and say yes obviously it would be of some interest but I think that that seems to me a less pressing need than other others that one has that are sitting there yes patiently waiting I didn't expect to be caught on so quickly but I'll ask I have a couple of questions here for I guess everybody and so I'd like my chance too and so and what I'm going to focus on at this point is issue of continued study of the heliosphere and solar system plasmas in general and it's interconnection intellectually with the astrophysical universe so I guess I'd like to ask whoever would care to answer if you could have just one more measurement from the solar system or an achievement from solar system plasma physics that would illuminate the cosmos beyond which what would you like to see from the program in the near future in the future sounds like being offered your last meal you've got one more or your last wish I wish for three more I find it difficult to choose between the origin of the solar wind the possibility that we may see cosmic ray acceleration at the termination shock of the solar wind and solving this interminable problem of magnetic reconnection which we know about perhaps the Earth may need a sphere but that's a rather universal problem I would like three if I may Charlie if I try and answer your question literally I want to get out into the interstellar medium I want to go through the bow shock okay so now we have I think that's clarified an issue and the next issue that I'm going to be Van, do you have a I'm very fond of the solar system I'm also very interested in keeping of course the two voyagers operating keeping Pioneer 10 operating so we make the best conceivable effort with the presence spacecraft to actually find and penetrate the radiation shock in the heliosphere that is a reasonable prospect but not by any means certain during the lifetime of these three missions otherwise of course Cassini is my favorite sort of more or less future mission and I understand there's an active consideration now for an orbit of Uranus I'd love to get some of these questions I outlined earlier on sort of settled one by one we have these magnificent magnetospheric laboratories and every one of them is a challenge and every one of them is different of course the magnetosphere of Jupiter is one of the grandest phenomena of the solar system and we're up to that working on that of course with Galileo at the present time I understand I think that's going well as far as I know and I'd like to see corresponding missions of Cassini of course is intended to do a similar type of investigation at Saturn Uranus and Neptune are very exotic magnetosphere is quite different than the Earth and so my vision is sort of my hoping compared to my colleagues here but I'm very fond of the Earth and the solar system I think we now have three votes for the heliopause mission which I would characterize as a slow unique but very cheap and so I would go on for that now I'd like to return to maybe pick up this thread a little bit Van you're fond of the Earth and this is I think a question devoted there I think if you look at the subject of Earth magnetospheric physics and sort of close by heliospheric physics that we can look forward to a few years of prosperity from the international solar terrestrial physics program and I think there will be a number of discoveries that come from that but I'm also mindful of the fact that this program is a result of 15 or so years of planning and so it's not too soon to start thinking about what might happen next in this particular field of science which is after all the oldest one and there is the question should we continue on in a vigorous way in this field and the planning I think will answer that question but as I look forward I begin to see a conflict arising in future planning for this subject I think there are those people who would like to study less and less with more and more that want to look more and more at the fine structures of the details within the magnetosphere and at the same time I also see the possibility particularly with the faster better cheaper techniques and some of the industrial developments that are occurring that it may also be possible to study more and more with less and less and send out particularly as one of our colleagues Carl McElwain speculated a thousand spacecraft to do this sort of work the communications companies are making plans like that now so the question is which direction would you go or how would you balance things out and finally can we answer Ian's question which is how do you show the public that you get value for money and interest for money when you do this not that I didn't ask a hard question that was a mouthful Charlie but very well stated I'm not sure that we should be starting to think about what to do next because there's a very large feat of spacecraft being launched and about to be launched maybe we should see what happens before we start to think about what's going to be done next and not rush into it too quickly my concern with that is that it did take us this long such a long time to plan ISTP and I'm just a little concerned about the absence of thinking yes can I phrase Charlie's question a little differently and I'll give you an analog of how we've done it in the field of origins of galaxies and stars and solar systems we laid before us a 25 year question and said conceptually 25 years from now what questions would we like to answer knowing where we want to be and as one example is if it exists we would like to be able to take a picture of a planet within 50 to 100 light years of earth with enough accuracy to see oceans, continents and clouds if they exist well at least you know where you are technically and well that's you know we're talking about 100 kilometers at 50 light years so you say okay I got to begin so we work ourselves back and we have a modest program which says in 5 years we'd like to take a picture of a terrestrial sized planet with 5 or 10 years with one astronomical unit resolution to at least get a direct sense that we could see a terrestrial sized planet but at least we have a roadmap and we know where we're going the concern that I have in relation to Charlie's question is most in the public because it's not visual they could understand that picture I just stated and we could fill in the physics behind it space physics is squiggles and lines and it's not clearly understood by the public that has a tremendous need and I guess the thrust of Charlie's question is could you formulate some basic questions that could be commonly understood by the general public about what questions would we like to answer within the next 25 years and if you know what kind of questions you want to answer you could then work yourself back and have a technological roadmap and begin to integrate the experiment was that the thrust Charlie? I mean I gave you two or three questions that I think are well posed easily described questions the origin of cosmic rays particularly at the very highest energies I see that as a bona fide serious scientific problem where there are a lot of opportunities for the answer and one where one can use space observations to help the nature of the gamma ray burst that of course has been one that has been around now in a quite different form over the last three or four years thanks to the Batsy experiment which has been a wonderful scientific puzzle and we would love to be able to understand that the nature of the flow of gas around black holes will put more pregnantly how our jets made in a wide variety of environments many of which involve black holes that's an engineering trick we do not know how nature does it it's like somebody else being your competitor being able to do something and we can't those are perhaps perhaps three of them I think in terms of communicating this to the public I think we all have a lot to learn about the means of communication and I think NASA has made great advances in this obviously visual images are more appealing to the spectra and we have to emphasize the visual but I think one of the areas where we perhaps don't emphasize as much as we might is the the actual technology, the actual trials and tribulations of getting an experiment or a mission to work and I think that there's a human component to that and an understanding of the difficulties we were talking about at lunchtime Galileo probe exactly at the right angle into the Jovian atmosphere I mean that is something that I again I think is communicable and of some considerable appeal and would be something that I think people would have a real respect for those who managed to pull off this trick Roger's three wishes on his wish list directly address Charlie's question about what you could plan for the future and avoid your concerns Ian because there aren't any missions this whole constellation of a dozen or more missions does not address any of those questions It's difficult because this is a mature subject in space research now we have been doing it since found the radiation belts in 1958 so it's almost 40 years and it's natural since the work has been done in a very very well very skillful It's sort of my hope compared to my colleagues here but I'm very fond of the earth and the solar system I think we now have three votes for the heliopause mission which I would characterize as a slow unique but very cheap and so I would go on for that now I'd like to return to yet maybe pick up this thread a little bit Van there you're fond of the earth and this is I think a question devoted there I think if you look at the subject of earth magnetospheric physics and sort of close by heliospheric physics that we can look forward to a few years of prosperity from the international solar terrestrial physics program and I think there will be a number of discoveries that come from that but I'm also mindful of the fact that this program is a result of 15 or so years of planning and so it's not too soon to start thinking about what might happen next in this particular field of science which is after all the oldest one and there is the question should we continue on in a vigorous way in this field and the planning I think will answer that question but as I look forward I begin to see a conflict arising in the future planning for this subject I think there are those people who would like to study less and less with more and more that want to look more at the fine structures of the details within the magnetosphere and at the same time I also see the possibility particularly with the faster, better, cheaper techniques and some of the industrial developments that are occurring that it may also be possible to study more and more with less and less and send out actually as one of our colleagues Carl McElwain speculated a thousand spacecraft to do this sort of work the communications companies are making plans like that now so the question is which direction would you go or how would you balance things out and finally can we answer Ian's question which is how do you assure the public that you get value for money and interest for money when you do this not that I didn't ask a hard question that was a mouthful Charlie but very well stated well I'm not sure that we should be starting to think about what to do next because there is a very large feat of spacecraft being launched and about to be launched maybe we should see what happens before we start to think about what's going to be done next and not rush into it too quickly my concern with that is that it did take us this long such a long time to plan ISTP and I'm just a little concerned about the absence of thinking yes can I phrase Charlie's question a little differently and I'll give you an analog of how we've done it in the field of origins of galaxies and stars and solar systems we laid before us a 25 year question and said conceptually 25 years from now what questions would we like to answer knowing where we want to be and as one example is if it exists we would like to be able to take a picture of a planet within 50 to 100 light years of Earth with enough accuracy to see oceans, continents and clouds if they exist well at least you know where you are technically and well that's we're talking about 100 kilometers at 50 light years so you say okay I've got to begin so we work ourselves back and we have a modest program which says in five years we'd like to take a picture of a terrestrial sized planet with five or ten years with one astronomical unit resolution to at least get a direct sense that we could see a terrestrial sized planet but at least we have a roadmap and we know where we're going the concern that I have in relation to Charlie's question the public because it's not visual they could understand that picture I just stated and we could fill in the physics behind it space physics is squiggles and lines and it's not clearly understood by the public that has a tremendous need to understand and to know and I guess the thrust of Charlie's question is could you formulate some basic questions that could be commonly understood by the general public about what questions would we like to answer within the next 25 years and if you know what kind of questions you want to answer you could then work yourself back and have a technological roadmap and begin to integrate the experiment was that the thrust Charlie? That's a super way of saying I mean I gave you two or three questions that I think are well posed easily described questions the origin of cosmic rays particularly the very highest energies I see that as a bona fide serious scientific problem where there are a lot of opportunities for the answer and one where one can use space observations to help the nature of the gamma ray bursts that of course has been one that has been around now in a quite different form over the last three or four years thanks to the Batzi experiment which has been a wonderful scientific puzzle and we would love to be able to understand that the nature of the flow of gas around black holes will put more pregnantly how our jets made in a wide variety of environments many of which involve black holes that's an engineering trick we do not know how nature does it it's like somebody else being able your competitor being able to do something and we can't those are perhaps three of them I think in terms of communicating this to the public I think we all have a lot to learn about the means of communication and I think NASA has made great advances in this obviously visual images are more appealing than spectra and we have to emphasize the visual but I think one of the areas where we perhaps don't emphasize as much as we might is the the actual technology the actual trials and tribulations of getting an experiment or a mission to work and I think that there's a human component to that and an understanding of the difficulties we were talking about at lunchtime getting the Galileo probe exactly at the right angle into the Jovian atmosphere I mean that is something that I again I think is communicable and of some considerable appeal and would be something that I think would people would have a real respect for those who managed to pull off this trick Roger's three wishes on his wishlist directly address Charlie's question about what you could plan for the future and avoid your concerns Ian because there aren't any missions this whole constellation of a dozen or more missions does not address any of those questions this is a mature subject in space research now we have been doing it since then found the radiation belts in 1958 so it's almost 40 years and it's natural since the work has been done very well very skillfully that it's becoming almost incremental now that doesn't mean to say the science is not good but it's very hard to get very excited about the next increment I think that the community involved in this has to rise up to this and find a way of showing the public that it is interesting and I'm sure they can do it it's a matter of having the right touch perhaps the important thing is to show that this is not an isolated subject but there is breadth to it and the ideas are in fact universal I have a different kind of response to Charlie's point there see to me the NASA has a magnificent set of missions either just recently launched or about to be launched in the next during the next year and I'm thinking there of course a wind which already I believe working quite well as far as I understand SOHO as of last week Cluster in the near future and of course the ongoing Galileo mission Cassini on the drawing boards all these are magnificent missions and what I'd like to see is a reduction in what you might call the turnaround time so when we discover something one of these missions it's not for our grandsons to do but we can do it ourselves within two or three years and this is a point that Mr. Goldman repeatedly emphasized and I'd like to join in that very hardly of reducing the turnaround time for response to new discoveries I think that would keep the level of interest and excitement at a much broader base now as you probably know I've taught the solar system astronomy for at least 17 years and it's an optional course it's a voluntary course and nonetheless 150-200 students turn up there every year and I've been a bit baffled my sense as to why they're so interested in the solar system astronomy but they come in and voluntarily I think that's an indicator of general popular interest in the subject Could I word the question a little bit more aggressively because this is a problem that I face as administrator and what's Huntress faces as the person in charge of the space science program up until recently we viewed our programs as separate entities and there was a given percentage of the budget devoted to space physics, planetary science earth science, astrophysics, you name it we are spending a very healthy amount of money on space physics now given that we've had this unbelievable series of launches around the world and another year or two we'll have all the spacecraft up and they'll be operating for such a long time we are getting a reaction from the space physics community to put it quite bluntly what have you done for us lately and how many new missions must we start now to keep the constituency going this I think is the hidden agenda in Charlie's question and I'm being a little bit more bold than Charlie was we have a real problem at NASA the budget is not just flat uncorrected for inflation it's coming down and if we live with the old world approach and in fact I've gone and France has gone to the National Academy and said we need you to help prioritize not within fields but among fields and given that we want to prioritize and given that we're looking for synergism we have a very tough problem and what we're faced with is the space physics community is very unhappy because we don't have a new start on the books for them whereas we have a multiplicity of new starts in the planetary program and we are moving very aggressively for a number of very significant new starts in the astrophysical portion of the program and I think we're dealing with the issues that Dr. Blanford has brought up but I'm very worried about what to do with the space physics and one of the thoughts we had was let's pause let's digest all the data let's wait two or three or four years and see where we go get the technology ready with instruments get the technology ready with spacecraft be able to turn around the program not in three as Ed Stone is now shooting for a year and a half on the new millennium program for instrumentation and for spacecraft so one approach we could take is let's hold off on new space physics missions but have a vigorous technology development program for new sensors and platforms that could accommodate those sensors maybe one could even think about not having passive measurements to the heliosphere interface but to blast out with electric propulsion at an unbelievable speed with small probes that just have particle physics measurements on them and you could really have a more proactive measurement but this is a real dilemma and I think, like, am I getting at the root course, Charlie? You're looking at me Well, you're looking at me Certainly the idea of having solar electric propulsion finally developed really pleases me this should have been done years ago and once we get it I think a new world will open up in terms of the kinds of missions we can have The remarks about the space physics community I think are well taken with so many spacecraft about to be launched or waiting for already up there I think a pause makes some sense however, I think there's already a problem and money for data analysis there's going to be so much data coming from these spacecraft that will require quite a considerable effort to handle it I think that five years concentrated data analysis wouldn't be a bad thing The problem probably with the community as a whole not even the space for this community is that it's now a buyer's market for research not a seller's market you're the buyer and there's less money than there used to be and you could be much more choosy The sellers, of course, 20 years ago were more or less being deluged with money the world has changed around the other way and we haven't quite used to it yet I don't think it's your business to keep space physicists in business as such, your business is to get the best space science you can, all kinds and this change in mindset is going to be rather difficult to make work but it has to be done unless there's more money somewhere Let's take a couple of questions from our audience would you, to start I'm David Cherry from 21st Century Science and Technology magazine I have a question for Roger Blanford you showed a fascinating slide of the shock of the supernova remnant of Tycho Brahe showing the side that has the shock on it you pointed out that the magnetic field lines are at right angles to the shock and the theory says they should be parallel now, I'm not asking you what's the answer but I do want to ask how do you approach the question how do you tackle that anomaly or how does anybody tackle it? I can tell you what I did and I can tell you it didn't work I tried to find a magneto-hydrodynamic instability that would account for that observation and I found it and then I discovered that it would not grow under the circumstances that would believe to be present at that shock front so I'm still puzzled by it I think in terms of understanding the phenomenon more I would like to see more observations of shock fronts in other supernova remnant to see how general it is so for me I'm a theorist so it's a problem in theoretical plasma physics but also one needs to know more about observations I think the significance of that is that the cosmic ray emitting electrons show a very sharp gradient in their density and that implies that they're being scattered very efficiently there which is an integral part of the theory of cosmic ray acceleration in that sense it tells you that accelerating cosmic rays in that environment is more or less unavoidable and so that was a very exciting interpretation of that observation The scattering of them is unavoidable is unavoidable yes because otherwise they wouldn't have just a sharp gradient in their density I have another question that I don't I'm not sure who to address it to about six months ago David Thompson and McLennan and Lanzarote published a paper that argued strongly that there's a coupling between p-wave modes in the sun and waves in the solar wind and they also had an argument not as well supported that yes there are g-waves in the sun they're coupled to waves that they identified in the solar wind my question is in two parts number one, if we had a complete free hand are there any technologies that we'd want to put up there to specifically refine those findings but secondly of necessity one has to say that this represents a failure of theory because the p-waves are not supposed to get beyond the corona and even if they did the solar wind is too turbulent to allow them to propagate what they do and then the solar wind gets so thin there aren't enough collisions to keep them going and yet they keep going at least I think I'm representing that right anyhow maybe someone would be willing to comment on what's wrong with our theory well that was a good paper of Lanzarotes are you contesting the validity of the observations I think the paper is wonderful too no it's a good paper I think it does show that our theory is wrong well I can't tell you what is wrong with the theory but I'm very happy to accept the observations and I think SOHO is going to address those same issues isn't that correct at least so yes helioseismology and the influence on the flow of the solar wind so I'm not a theorist so I'm not I'm a competent to judge the quality of the observations but not the implications I would say thank you for your questions yes the symposium was billed as related to the plasma universe and you're concerned about how to interest the public the public of course interested in cosmology and Dr. Axford referred to Hanna Salvein and his pioneering work with plasmas but we know that his model of the universe was different than the dominant model that we live under these days I wonder if there might be some thought of how research might be directed to explore the plasma kind of universe that Hanna Salvein was proposing I think what you're using I'm afraid I'm not a great expert on Dr. Alfane's cosmology he certainly was one of the pioneers of magneto-hydrodynamics and again in that context certainly one of my scientific heroes I don't think there would be a very broad constituency for his particular ideas about cosmology at the moment because there have been many observations most I think fundamentally that of the cosmic microwave background which have fit in so nicely with the hot big bang in the evolutionary cosmology and although there are many important puzzles that are going in cosmology I think that most scientists now at least accept that as a starting point Any other questions from the audience? Dan, do you have any questions? I want to poke around a little bit with ground-based measurements you talked about the radio waves more and more we're coming to realize at NASA that we have to pay attention to the synergism between ground and space-based measurements in fact the folks in space science and now an investor in the Keck Observatory in Hawaii how about radio astronomy? this is something that we haven't looked at for a while at NASA what do you think we ought to be doing or looking at in the field of radio astronomy and I open it up to all I would think interferometry space interferometry, long baseline you have the chance to have baseline lines of several astronomical units which is about the best angular resolution we'll give the best angular resolution you can expect at this time from anything I think that is a fairly straightforward matter the Japanese are already starting in the near future with interferometry sorry yes the Japanese already have a space interferometry going up I think that this kind of approach could lead to the best angular resolution of any part of the spectrum you can have for this time and probably is worth following up it's got such a big deal I'll just flesh it out a little bit there is a mission VSOP launch next summer in which NASA is already a collaborator and in fact causal proposals have already gone out and been answered it will be followed we hope by a Russian mission Radio Astron which will have a slightly larger baseline I think the astronomical these will be wonderful opportunities because they will give you better angular resolution but the concern about going to very large angular resolution is if you don't have a large enough aperture then you may be resolving out all the structure that you can detect and so it's not just a question putting a 10 meter dish on a year away you've got to put a large enough dish at some distance so that you can actually see something with that sensitivity the other frontier in radio astronomy in space is low frequency radio astronomy around below the frequency for the ionosphere and again I think there are opportunities there for carrying out cheaper missions in space because obviously it is much easier to make an antenna in space operating at these low frequencies and I think that there are of course many plans on the drawing board for low frequency arrays in space and I think that's a possibility of course Bernie Burke is highly in favor of a radio interferometric station on the moon and that has a certain appeal but I have a little trouble swallowing the practicalities of that actually well one of the things that we worry about if one has an overwhelming need for a radio telescope on the moon we ought to do it but we shouldn't put a radio telescope on the moon to justify a mission to the moon and that's where I think we have to be very very careful yes I think it's hazy right now could I do you have a question for us? well I just wanted to sort of summarize where I right now where I think we are with respect to your goals that you express some near term goals and I think a certain comfort level that we have a lot of interesting missions on the right now and in the future that we will be reaching those I'm excited about seeing what those results are and Dr. Axford you think that we should be spending a little bit more on data analysis so we can get the most out of these results and then make a plan for where we want to go next because we don't, as Roger said we can expect the unexpected and that may be in the data that we are collecting right at this moment and Roger you're looking at as I understand it a new kind of parameter regime the hard X-rays, the gamma rays between opening with new kinds of resolution angular resolution, spectral sensitivity a whole new way of looking at these phenomena that we have never been able to look at before is that kind of the sense of you all right now I'd like to see the quick turnaround time I mean that's the way science really works really like to work I'm sure we can all agree about that that's right, you're a laboratory scientist this is the way I started off if you find out something today and you've made it again and see if it's still right or not and that kind of thing is very difficult in space has been extraordinarily difficult because of these enormous delayed times and turnaround times I'd like to see us turn around after a new discovery two years later or less we're up there looking into it I think that's excellent I think I have a little trouble with these ponderous 25 year plans that's not my style of doing science well for me this particular seminar has maybe more than any other shown such a breadth of astronomy the different areas that this field really touches on that it is difficult to think of just one big question that all of it can be embraced into there are just so many areas that it's out in front of that really what it looks to me like it's called for is a diversity of approaches and some parts of the field it's a real good plan with all the missions for the present and we need to analyze those and other parts of the field the parts that you were talking about Roger really needs some new technology infused right now and get going and try to figure out the answers to some of those questions Astronomy is an infinite subject I think anyone that lies out in a sleeping bag on a mountain in Montana realizes how infinite it is we will not run out of problems with astronomy believe me Well that seems a good place to end on I want to thank you all very much for such wonderful enlightening talks and for opening up our understanding of this very interesting and complicated field and I want to thank the audience too for their attention the speakers will be around for a little while and you can come up and talk with them and ask them some questions you might have been afraid to ask Thank you