 Good afternoon and welcome to today's energy seminar. We have a very exciting talk on a very big science achievement today by Chris Young from Lawrence Livermore Labs and introduce him. I've asked Mark Capelli from the Department of Mechanical Engineering here who was in fact Chris's thesis advisor not long ago to give a personal introduction to him. So Mark. Well, welcome everybody. So my name is Mark Capelli and as John said, I'm in the Department of Mechanical Engineering and it's a pleasure for me to introduce Chris. Chris received his bachelor's degree, master's degree and PhD degree at Stanford. So he's cardinal all the way. Can you hear me? Yeah. His bachelor's degree was in engineering physics and his master's and PhD was in mechanical engineering. So his tenure here is close to 10 years. Now that would be roughly I guess 30% of your life at Stanford or I would say 40% of your memorable life because the first six years of your life, nobody remembers that anyways. So his research and his PhD involved studying the intricacies of plasma accelerators that are now widely used for space propulsion and much of what we learned about how those engines perform came from some of his research. Now he's a target designer in the inertial confinement fusion program and the high energy density physics program at Lawrence Livermore National Labs. He started that in 2016 and now has co-led and supported a variety of the campaigns there. Using the experiments with very large multi-physics simulations, he's going to show you some of the outcomes of those simulations here. And if there's anyone here, any students here that are involved in SIMPS, Chris is a graduate of SIMPS. SIMPS is the improv group here at Stanford. I would say that next to plasma physics, SIMPS was his second passion here at Stanford. So Chris, I'm going to turn it over to you. Thank you, Mark. Appreciate it. Thank you so much for the introduction. It's always great to be back on campus. And I'm excited to share a bit of context into the really awesome results that we've gotten recently at the National Initiative Facility. Has anyone seen the 60 Minutes episode that came out in January? A little bit awesome, or some of the news articles that came out. Great, if not, that's okay. I'll hopefully tell you all you need to know, but provide some context around what was going on. And let's figure out where I'm standing here. We've gone through the introduction, but just again, my name is Chris Young. I spent a whole lot of time here and really, really great to be back. And I've been about six and a half years at the lab. So just starting to really get a handle of what's going on in my job there. So I'm one person standing up here, representing the work of a cast of thousands. Many people have spent their whole careers, decades working on the problem of fusion. And this work is a collaboration between industry, academia, and the national labs. And I'll give a special thanks to Dr. Nathan Meezan who helped put this talk together with me. We actually gave a joint version of it in this building upstairs a couple months ago. And he is another predecessor of mine through both Mark's lab and then into the initial confinement fusion program. So an outline of the talk today, give you a bit of a history of the fusion program at the lab and a physics introduction to the physics of ICF and what we're trying to do. Talk a bit about the NIF facility itself. It's the world's largest most energetic laser. And the targets we shoot are some of the most pristine, perfect materials that we can manufacture. We'll go through the program as a whole and some major turning points, which led to the big breakthroughs that we've had recently and talk a bit about what we're doing next. So as I'm sure you're all aware, fusion is what powers the stars. And if we can bring this power and harness that for energy production on earth, that would really be a game-changing technology for humanity. If you're not familiar, fusion is the process of combining light elements into slightly heavier ones and releasing the binding energy of the nucleus in the process. It distinguishes it from fission, which is the splitting apart of large atoms into mid-sized atoms. All of the elements are produced either directly via fusion or indirectly through supernova explosions in the universe. And all of the energy radiated towards earth from the sun, sustaining life, was originally produced through fusion. And there is a lot of naturally occurring deuterium in seawater. So if we were able to collect that and harness, release that energy through fusion reactions, we're basically looking at a limitless source of energy. So the potential use of this is enormous for humanity. When we turn to fusion research in particular, there's many different approaches with lots of wide-ranging applications. Looking at the top left here in terms of confining a hot fusion plasma, you basically have three options. One, you have to be the size of a star and confine under your own gravity. Since we're trying to do this in the laboratory in a building, that's not going to work for us. So we have to either use strong magnetic fields, which is like the Eater machine that they're building in France, or a Tokamak, if you've heard those types of names. Or you can use lasers to deliver a whole bunch of energy and squish this fusion fuel under its own inertia, and that's called inertial confinement. And that's what we do at Livermore. Over here is a few different types of the inertial confinement fusion architectures. You can hit the fuel directly with the laser. We call that direct drive. We can put the fuel inside of an x-ray oven called a horom. We'll be talking a lot about that today, and we call that indirect drive. That's mainly what we do at Livermore. And you can also use a magnetic field to basically have store a bunch of energy capacitors and dump it down a wire really fast in what's called a Z-pinch configuration, and you can confine a cylindrical plasma that way. And there's of course many applications for this work in clean energy research to fundamental science studying the universe, the interiors of stars, basically materials at very extreme densities, temperatures, and pressures, and the conditions that occur in nuclear weapons explosions, which is why we, the Defense Lab, are also involved in this work. So to give you a bit of history as to how we got here, the quest for inertial fusion ignition has been a 60-year journey, and it really started the idea for ICF is as old as the idea of the laser itself. And very soon after the laser was invented, people realized that this could be a mechanism of delivering a lot of energy into a small volume to initiate fusion reactions. And there was a seminal paper by John Knuckles, one of our early lab directors, which was kind of outlined this process in the open literature for the first time. And since that time, NIF has been home to an array of ever-increasing lasers in size and scale and energy, culminating with the National Ignition Facility 1.9 megajoule laser, which is the largest most energetic laser in the world right now. And you'll notice that NIF came around, right around, and kind of the concept of NIF in the beginnings can be traced right around the same time when we stopped underground nuclear testing and switched as a nation to the science-based stockpile stewardship model for ensuring the safety and security of our nuclear stockpile. And NIF is one of the only facilities in the world able to make these super-high energy density states. It plays a very important role in that. And so there was this study by the National Academy of Sciences in the 1990 timeframe that said, you know, we need to achieve fusion ignition and go after, you know, very high gains, right? We're going to come back to the concept of gain. That's just the fusion energy liberated through the process compared to the energy that we had to invest to initiate those reactions. So a gain of one is energy break-even. And we would like to be operating somewhere around, you know, gain of 100 if you were going to say build a power plant based on this technology. We've spent a whole lot of time trying to pass gain of one for right now. But rather than go after that gain of 100 huge facility first in the 90s, it made more sense to take a smaller step and go after a small to mid-sized gains of 2 to 10. So that was built into the idea of NIF. Demonstrating ignition should be our highest priority. And it took a little bit longer than we were hoping, but as of December of last year, we've finally gotten there. And another point is that, you know, the only possible technology in the 90s when this was being conceived that we could kind of set up at scale at that time was to use a glass laser. So if we were going to rebuild NIF today, there are many more efficient laser architectures that we could use, but at the time it was amplified neodymium glass lasers. And we could take advantage of all the existing experience infrastructure at Livermore. So that was the natural place to site this facility. And they recommended that we recognize ICF primarily as a defense program, not as an energy program, again, for the reasons that I mentioned. So the rough timeline is, you know, in 1990 we have the idea we need to build NIF. In 93 we got the commitment from the Department of Energy to build it. We broke ground in 97. We commissioned the laser with the first experiments in 2009. Really in 2011 is when we first introduced the deuterium and tritium fusion fuel and started trying to make neutrons. So we've had a robust program over the last 12 years. So I've said the words inertial confinement fusion a lot now. So what are we actually doing? The main idea is that we're going to implode a sphere. And that lets you take, you know, something and increase its density and pressure many, many times over to reach the very extreme temperatures, density and pressure that we need in order to initiate fusion reactions. And here's the title of that seminal paper in nature in 1972 that laid this out. And actually George Zimmerman is still working at the lab. He's still developing the code that he started way back then to model these systems. And he remains an amazing contributor. I kind of mentioned this before, but the direct drive concept we're just going to put the fuel inside this shell. We call it the ablator because its main purpose is to absorb that laser energy and just blow up. And you get an equal and opposite reaction inward that's going to compress that fuel as it travels in. You can think of it like a spherical rocket where the rocket exhaust is pointed outwards and the rocket's traveling in towards the origin. But as you can imagine with direct drive, say you're taking a water balloon and you're trying to squeeze it in between your fingers and you're trying to keep it exactly spherical, what's going to happen? You're going to get some bumps that's going to squeeze out in between all the parts where you can't exactly balance everything. And there's a lot of laser plasma interactions going on around this that is preventing you from getting that laser light exactly where you need it to balance it perfectly. So it turns out that maintaining your spherical symmetry is pretty challenging in direct drive. But we do have a facility, the University of Rochester, the laboratory for laser energetics or LLE has a smaller laser that studies this extensively. But at Livermore we go more with the indirect drive approach and that adds this HORAM or a radiation cavity, it's a German word, you can think of it just as an x-ray oven whose job is to take that laser light coming in and make a bath of x-rays and because ovens are very good at redistributing the heat in a nice even way, it's much easier to push on this thing evenly from all directions and maintain a spherical implosion. So we usually use cylindrical HORAMs here, we have two holes on the top and bottom which are pretty stupidly named, the laser entrance holes or LEHs. X-rays bounce around in here again with the capsule, we have our deuterium tritium fuel. In this particular scheme we'll have gas in the middle and a shell of cryogenically frozen DT ice and the goal is to get that thing going at about 400 kilometers per second to give it the kinetic energy it needs to spark and kind of start off the fusion reactions when this thing implodes to about 30 or 40 times smaller in radius than it started. And that's exactly what's illustrated here. So we illuminate this with x-rays, the ablator blows up, we get that equal and opposite force inward, it accelerates, it decelerates, when it stops we call that stagnation and that's kind of when the fusion burn starts happening and then the name of the game is try to keep it there cooking as long as possible before it's going to blow up and dissipate all that energy and then we stop making fusion reactions. And so the picture right when we're burning is we're trying to go for a hot spot that's formed from the DT gas that's kind of lower energy or sorry lower density but very high temperature 5 keV is you know a few million degrees Celsius on the robustly burning ones we might be five times the temperature of the sun when the fusion reactions are going and then that's going to be surrounded by the shell of colder DT that's been compressed up to about a kilogram per centimeter cubed of density. All right so there are tons of physics challenges this is why it's a very hard problem but also very rewarding physics problem to work on. We have to bring together these big multidisciplinary teams of people with expertise kind of all over the map. So on the whole ROM side and this is where I live most of the day you know we're worried about how we couple the the laser energy into this system and use that energy efficiently and and also the the HOROM dynamics kind of determine how well we can press on this capsule symmetrically throughout the whole implosion. On the capsule side there's a lot of hydrodynamic stability that you have to worry about these are classically Rayleigh Taylor unstable systems as you have shocks and accelerating decelerating interfaces of different density kind of all mixing together and then as I was mentioning you know trying to figure out that yeah we want to add as much energy as we can and we want to minimize all the losses as much as possible to get the favorable energy balance and lots of fusion reactions. So to achieve ignition really extreme conditions are required and this puts some numbers to that. I kind of mentioned this already we used deuterium tritium because that is the easiest fusion reaction to to conduct it has the highest cross section for a given temperature. The goal here the product of that is a fast neutron that basically goes out and leaves the system and this slower alpha particle or a helium nucleus and the name of the game is trying to get enough stuff there to stop those alpha particles and get them to re-deposit their energy in the hot spot thereby continuing to add heat and heating everything up more and we have this nice feedback where the cross section for DT actually goes up as it gets hotter so as you get hotter it's easier to fuse more fuel and so on. But it takes really really high densities like 100 grams per centimeter cubed peak central density really high pressures 400 gigabar like we're talking interior of planets type pressures. Mark mentioned I was going to show you a simulation right these experiments are very expensive we don't have many opportunities to take them on the facility so we do quite a lot of modeling work with large multi physics simulations that run on the supercomputers at Livermore and we can model all parts of this the radiation transport of the lasers coming in the response of the horror materials blowing up the x-rays kind of making this rocket effect happen and then all the nuclear reactions and things that happen on the inside of the capsule this is a bit of an older design with a longer pulse but it kind of illustrates the point we put in a little bit of energy in the beginning and that kind of launches some shock waves and sets up the implosion the way we want it and later on in time we come along with this kind of the full power of the laser really hit it and that's when the radius really starts to go down and compress very quickly and you can see here the time scale we're talking about is 10 20 nanoseconds the billions of a second so very very short time and the fusion reactions are cooking in there for about 100 picoseconds so very very fast so you can imagine energy is lost kind of in many different ways along the way we start with a two megajoule laser and it would be great if we could get all that energy into you know directly helping to start those fusion reactions but this is kind of the reality of what we have to deal with some of that energy gets just scattered right back out of the Whoram and it goes into producing hot electrons and low density plasma kind of this you know as we see from the simulation of how stuff is going to come in and the the wall is going to blow up and start filling the Whoram and block the laser beams so but the majority of that energy goes into x-rays and a lot of that has to go to heating the Whoram walls right it's getting the oven hot enough so that it can cook our capsule and some of those x-rays are going to escape through those holes which we need to let the lasers in and unfortunately they also work as they work against us in that way so of the two megajoules that come in we get about 150 to 250 kilojoules onto the capsule a lot of that goes into ablating those outer layers and only maybe 10 or 15 kilojoules actually gets converted into kinetic energy of that DT shell that's going to start moving inward and do the compressive work on the fusion fuel on the inside and we would love to convert all of that into the internal energy of the fuel except as I was mentioning with the the you know asymmetry keeping it spherical is really hard so if we don't push exactly the same on all sides and we squish it a little bit you know like a pancake or a little bit like a sausage those are the words we use of that residual kinetic energy is going to rob your hotspot so that's that arrow and then finally you have some hotspot and internal energy you're going to make some fusion reactions now it's a competition between everything that's going to the things that are adding energy to the system which is the fusion reactions and the alpha particles that you're able to stop and that's in competition with all the loss mechanisms of radiation conduction and the mechanical work of this thing is going to start expanding and it's going to cool when it starts expanding so after all that energy flow we're going to get some amount of energy back out through the fusion reactions and for a long time this number was a lot less than two megajoules but in august of 2021 we had our first very near ignition shot 1.3 megajoules came back we were very excited to see that and then in december of last year we hit 3.1 which was for the first time you know a net energy gain compared to those two megajoules of laser energy that we put in now it's not quite that easy because 320 megajoules came out of the grid to charge the capacitors that we need to run the laser so from a power plant perspective three is still less than 320 but nif is not meant to be a fusion reactor it was meant to be the demonstration technology kind of that there's no fundamental physical process that is impeding this from working and now there's actually several startup companies out there that are pursuing different types of architectures some in the inertial confinement fusion space trying to get this number up and make that yeah make that math work for power production and because we have all these different energy exchanges I'm just noting that there are many different kind of efficiencies or gains that you can describe and so don't get confused if you hear people talk about well I got more energy out of the capsule than I put into it or I got more energy out of the fuel than I put into it but you know we passed gain of one on these much earlier than we did on on the full target all right so now we'll talk a bit about the facility itself primarily or primary experimental facility for doing ICF is at Lawrence Livermore it's in a very large building it's about the size of three football fields and as I mentioned 320 megajoules of electrical energy from the grid get converted to 1.9 megajoules of UV light and at the end on one side there there's this nice 10 meter diameter target chamber that's under vacuum and so all those 192 beams that you know all through this part of the facility all kind of come up and plug in on all sides and there's some really cool movies on YouTube you can check out like how this works sitting in the very middle of this on a little arm is our whole room and it needs a whole bunch of hardware to keep it cold I mentioned it's cryogenic frozen DT ice on the inside there so that starts at 18 Kelvin and takes a whole lot of you know thermal management to grow a nice ice layer and keep it all uniform and so that's about one centimeter large and then on in the inside of this thing that the shell of material that's actually holding the fusion fuel is only about two millimeters in diameter so crazy span of length scales here right takes this giant facility to deliver that energy into basically the something the size of a peppercorn the each laser beam travels about one and a half kilometers through the facility and it gets amplified through flash lamp pumped amplifiers four times before it gets diverted into the target chamber and so there's that picture of all the beams kind of coming in and we have a bunch of diagnostics and looks really cool it looks so cool that they filmed part of a Star Trek movie in there and called it the the reactor core or something here's when the target chamber was installed in 1999 I think a bunch of people came on site on Saturday to come see it and it weighed a whole lot a bit more on the whole room it's about one centimeter long and six millimeters in diameter and we cool it to about 18 kelvin before our really high performance shots here it is in the the cryo shroud here that's kind of keeping everything cold and then you know in the last minute before the shot it just kind of opens and then we go really fast we need heaters there's some windows in here so that we can get x-rays out to our diagnostics to see what's going on and we need all these dimpled shields here to keep the laser safe because we have the world's largest laser if that reflects off something in the chamber and goes back up a different laser beam or laser pathway that's going to be really bad news so we spend a whole lot of time making sure each shot shot is safe for the laser the capsule itself that's going to sit basically in between two pieces of saran wrap but it's very very thin it's about 20 nanometers we call that the support tent that's holding the capsule in the middle there we make this out of CVD diamond or ch plastic or a summer beryllium but mostly what we do right now is diamond here's to scale what it looks like to start at two millimeters and compress down you know 30 or 40 times and basically this x-ray emitting part in the middle of the hot spot is something less than the diameter of the human hair it's it's around 100 microns we need to get the fusion fuel in here somehow and we've used a series of continually decreasing fill tube sizes so this guy right here is five microns it used to be 20 and then 10 and five and now we can do two sometimes although those break a lot more often but just incredible engineering to you know laser drill this five micron hole and get a tube in there to fill it with the dt but all of these engineering features kind of we can't get away from them we have to engineer around them and these all provide some issues for us later in disrupting the the perfect 1d spherical implosion that we're going after now here's a picture inside the target chamber the hole ROM is inside this white circle and we have some other diagnostic arms there around it and what happens after the shot I think on the ignition one we burned it you know way back here and that was the first time we've done that one slide on diagnostics this is a huge area of research and amazing engineering but they've provided really key insight into our experiments as you can imagine it's very hard to make any progress if you cannot see what you are doing and see what happened so we have things like x-ray cameras and neutron cameras in some case time resolved so we can get a bit of a movie as to what's happening and we have different platforms that look at different parts of the implosion so we can make sure we're doing what we're intending to early on all the way to the the full up integrated test we can look at gammas and different self-emission and backlit radiography okay so here's one slide you all have my job for a second you are the ICF designer what kind of parameters do you think you can vary in your next experiment here in the whole room and the capsule just throw it out there dimensions yes well your laser is staying the same size so you don't have a lot of play in how big you can make it materials of all these components yet the particular way you you put the the diamond on here or what material you make the whole amount of any other guesses thoughts no wrong answer all right point is there's a lot on the whole on side everything about the laser where you point these beams what particular pulse shape you put on it the wavelength of the laser as we mentioned all the materials and their their dimensions there is a whole bunch of kind of derived metrics we call these like the rocket quantities about how fast you're going to go the different growth factors leading to what your hydrodynamic stability is going to be so this is a huge huge parameter space and as I'll show you very few experimental opportunities to test these things so we really have to to use codes and simulations and theory and try to put it all together to to make progress without testing every idea on the facility so now I'm going to do a little bit of a time series here to identify major turning points in the program that kind of led to the most recent results and we're going to plot this as thermonuclear yield versus year on the facility each one of these is a particular experiment so in 2011 when we started the DT experiments we were using plastic capsules we had a fantastic design that everyone had been working on for years just on paper and in one dimensional and two dimensional codes and turns out three dimensional reality was a bit different and there were some other things we hadn't thought of and weren't modeling taking into account and so by 2013 though by changing the design we call low foot to high foot we demonstrated alpha heating in the capsule for the first time and really the the gain from these early years was we were figuring out how this was working and we were developing all the experimental platforms we needed to again see what we were doing and get the diagnostic suite all set up and so just kind of getting all these gamma spectroscopy x-ray emission of the core going but at the end of this era we're still a factor of a thousand away from fusion ignition where we need to be in 2013 the laser pulse shape was changed to help mitigate some of the hydrodynamic instabilities and we go from something that looks like this remember we're trying to keep this a smooth sphere coming in evenly from all sides to something more like this that had much fewer hydrodynamic instabilities also going to a shorter pulse that helps it be less unstable and also helps just kind of get everything done quicker before the whole ROM has a lot of time to fill up with plasma and start blocking the laser beams and stuff and these are three-dimensional simulations in the code hydra that we run and actually so these features right here this x those are the impact of the capsule support tent that saran wrap that's holding the capsule where it touches kind of launches these jets and then also this is the fill tube here which kind of on every experiment like oh yep there's the fill tube jet we can't get away from it we then moved to diamond and this really helped we were able to use a lower-horon gas pressure which cut down on a lot of the laser plasma interactions that were happening in the whole ROM and that helped things get a lot more repeatable and able to be modeled well in the codes it's also improved our symmetry control with the shorter laser pulse again kind of getting everything done before the whole ROM shuts down in 2017 we again first demonstrated alpha heating with diamond and I've mostly said all this already but again using all of our different diagnostics to be able to check that we are remaining round at all times throughout the implosion and that was a key advance in this period so then we made the shells bigger and that might seem like an obvious thing to do but again the size of our laser is not getting bigger with us so that means learning to be more efficient and getting finer and finer engineering control kind of over all aspects of the process and so we increased the capsule size relative to the whole ROM so we're using our energy more efficiency implosion symmetry gets harder now but we were able to build in some new tricks to maintain that and by 2020 we achieved the burning plasma state and so physically it's starting to be a different regime it's where you're starting to make enough alpha particles that the heat and energy from alpha particle deposition is starting to change what's going on so in the analogy of say trying to light a wood fire right you're providing a spark for a long time spark went away nothing happened here in the burning plasma regime you're you're catching a little bit of the fuel and you're you're getting enough heat back kind of about equal to the amount of energy you're putting into it in in terms of just the sparks that would be like the kinetic energy of that shell in the the big long flow chart of energy that we were talking about anyway it's the the sign that you know something is fundamentally about to change and we're getting very close to that cliff where ignition is going to really take it off and the thermal instability is going to kick in and so how do we do that we scaled up the capsule more than the whole ROM so that makes it more efficient but we had to improve our control over symmetry and so one thing that we use a lot now is called cross beam energy transfer but you can take advantage of a particular laser matter interaction where by changing the laser wavelength subtly like an angstrom or less you can kind of pass energy between laser beams using the plasma as a mediator and that kind of helps you take energy away from from certain parts of the whole ROM and put it say in in other parts of the whole ROM where you want it and getting good engineering control over that was really important and also from our target fabrication side you know throughout this whole process every year the quality of the targets are getting better the the number of defects are going down with time and that definitely helps things so finally in right August of 2021 I kind of mentioned this before we had this guy right here the gain 0.7 and loss in greater than one so there's something in fusion called the loss in criteria it basically says you need to get something hot enough and dense enough for a long enough period of time in order to get a fusion ignition it's pretty easy to get two out of the three of those things it's very hard to get all three at the same time and keep this plasma confined that just wants to you know blow itself up so we we got to a part where you know we had so much alpha depth alpha production and fusion reactions that we exceeded loss in criteria for the first time that was the first time any experimental facility in any type of fusion configuration achieved that but in terms of the gain and that national academies report definition of ignition which said gain one we still haven't surpassed that milestone yet and we did a few repeats actually this is probably the most repeated experiment that we've ever done trying to do exactly the same thing and you can see they all fell short kind of illustrating the extreme sensitivity right at the beginning of the yield cliff where any little thing can kind of drag you back down and that competition between the energy gains and losses the losses win but how did we get to the threshold of ignition and the the loss and greater than one shot we made these holes smaller again that might sound like a really obvious thing hey you're losing energy out these holes how about you plug them up a little bit but again we need to be able to get the lasers inside and symmetry control basically by restricting where you can point the laser beam all gets really hard when you do that we also changed the laser pulse to not push quite as hard but push longer and experimentally the system really seemed to respond well to that and that August shot had the most pristine capsule with the fewest defects fielded to date and we have not actually been able to recreate a capsule that pristine again so it was really a unique and exciting time and then what happened we upgraded the laser a bit we had 1.9 megajoules to play with and then we got to 2.05 just for these couple shots and doing so allowed for slightly thicker capsules to be used and if you can go thicker that provides a little bit more margin and robustness to all these little defects in the fill tube in the tent and everything that's trying to kind of rip this apart as you are imploding it at 400 kilometers per second and so here in December for the first time we surpassed the amount of laser energy that we put in and got gained 1.5 and again with a capsule that was not quite as good as that other one and so the fact that we were still able to do that means all right we're getting better in a more robust regime and as I mentioned the things that enabled that we got a little bit more laser energy we thickened the capsule we continued on this track of pushing longer not necessarily harder and keeping everything around and in doing so we we finally surpassed the ignition threshold so what are we doing right now our current campaigns are trying to improve performance and robustness and it's kind of a funny business to get in you know we've spent decades and decades and decades trying to just get ignition with kind of single-mindedly focusing on this goal and you do that and the next day the goalpost just moves down like great you got one give me 10 so 10 megajoules is kind of the next level that we're aiming for we're going to continue optimizing around the the design that gave us ignition playing with those rocket parameters like the velocity and the different thicknesses and the laser pulse we have campaigns further increasing efficiency right we have a playbook that kind of worked how far can we push this this is one of my campaigns this year just trying to make the cylinder and the laser entrance holes smaller and deal with the symmetry challenges that come with that we have some different ideas about how to increase compression right you can increase the the confining material around the hot spot by shocking it up to even higher and higher densities but there's trade-offs associated with that and we also have some different horon geometries like this guy called the frustrum which can use less surface areas so be be more efficient again trading off with other challenges like symmetry so summarize the outlook for fusion research is bright right now it took longer to reach fusion ignition on nif than we originally envisioned in 1990 but we can say now we've kind of attained the the original goal for both the performance and then now all the scientific inquiry that can follow again nif is not a fusion reactor we're not going to plug it into the grid and start producing power but by attaining this ignition and demonstrating this you know we've kind of shown that there's nothing physically that's fundamentally holding us back from going to higher and higher gains the physics works it's it's going to turn more into an engineering type of problem to get a fusion reactor going and many startup companies are trying to do exactly that hope i was able to show you that you know there wasn't one Eureka moment that just kind of suddenly everything worked right it was a very long slog performance made in incremental steps continually improving all parts of the process continuing to improve our diagnostics and engineering control and our simulation capabilities getting larger and larger computers being able to go from 2d to more routine 3d simulations things like that so far we have not been able to repeat the the ignition experiment we actually haven't had a real attempt at it yet but in may next month we'll hopefully get a second one on the board and start assessing how what the variability and robustness is in this new regime and as i mentioned we have several new campaigns that are continuing to try to push forward and get to the 10 megajoule limit the next few years nif will be upgraded either in power and energy and that should enable you know quite a bit more more work and more margin to to continue improving this so so with that i will say we are hiring if this sounds exciting to you i'd be happy to talk to you and there's you know besides just fusion livermore is an amazing place to work with a whole bunch of very very smart people across all different fields so highly recommended but thank you for inviting me on such an exciting and spell-binding story that you shared with us today thank you so much we now have time for any questions from students or others if we have some tactical experts up here in the front anybody want to see a hand back there yeah i'm i'm not exactly sure about that but it's public it's a line item on the congressional budget every year so you can look it up probably in a hundred million range but that's spread among a whole lot of different pieces okay hello is this working okay um yeah so i was just curious i know you said that this is still like initial phases and you guys are not trying to build a power generator or anything but with that experimental setup is there any mechanism to introduce like more fuel into the reaction or are you constrained by whatever fits into the initial package right yeah it's basically the size of the laser driver is going to set kind of this size of your target and how much fuel so we we can still go a little bit bigger um and the trade-off there is with more fuel and or like a larger size we won't be able to push it as fast so then you're getting into all those engineering trade-offs with kind of the rocket equation stuff that you know great we might have more fuel to burn but if you give it a smaller spark it won't uh it might not take off and you won't hit that ignition threshold we got one in the back um sounds like you spend a lot of time trying to maintain that symmetry and sometimes symmetries introduce instabilities which i think is what you saw in the direct um configuration and so i was wondering has anyone ever considered um introducing some asymmetry to the problem which um can can uh i guess cause more predictive can result in more predictability um sometimes that sort of technique is used in different physics problems um and yeah because of the predictability might be able to increase your yield because you'll better understand the result so yeah sure yeah there are there are a few papers on that topic um you know one idea is to compensate for known asymmetries in the drive so like if you know you're gonna end up squishing this way you can start with a a a spherical capsule to start to start with so basically it'll compensate out um also yes exactly there's uh you know we can kind of induce whatever asymmetric uh trajectory we want by how we partition the the laser energy in the different beams um so far the majority of the implosions really have been focused on trying to stay uh round kind of throughout the the whole implosion but i think there's there's some interesting things to look at in that space yeah so presumably you you have um um well you have this huge simulation capability and you also have all the observational capability um you didn't show any comparisons of the of the the shapes of things with the simulations and and so on but i'm sure you i'm sure you're doing them and so my real question is with this a parameter space as big as you have obviously the simulation side is going to be the way you explore portions of that are you comfortable enough that you that simulation capability is is good enough that that you really can optimize the exploration with a small number of shots or is there more to do on the simulation side yeah absolutely and there's a whole chunk of our program devoted to just improving predictive capability of the Whoram you know that's really where uh a lot of the the challenge comes in um i'd say right now we're kind of in a hybrid mode where the simulations are good at certain things especially early time before the Whoram fills up with plasma and you really start getting these complicated uh laser matter interactions uh and then for the later part in time we have different analytical or semi empirical models kind of informed by our previous experiments say since you mentioned shape like that's that's a huge one we spend uh you know for every high yield dt experiment that we go for there's usually at least one or two symmetry tuning experiments to make sure it's round in in those conditions um and that is something that we've as the continual battle to kind of massage the code into agreement with with that last question over there if you don't mind i'll put you in an awkward spot you did a nice overview of laser confinement magnetic confinement etc if somebody was going to work wanted to work on or invest in the most likely first to produce commercial power right i'll ask you to although i know you're coming from the laser side yep what's what's on track to get there right um our lab director answered this question at the doe panel after the the press conference but it yeah magnetic fusion has had much more investment into the engineering side and uh turning it into a practical reactor than icf has um however we haven't demonstrated a burning plasma or fusion ignition conditions in a magnetic uh device yet so on the inertial side we have i'd say some catching up to do on on the technology required to actually put this into a power producing configuration i'm not sure right now which one will get there first um but kind of uh you know we we should invest in all of them and uh a set of it in thank you one last time there is this kind of it to me it's interesting that as you mentioned a lot of companies startups are trying to actually do this right now so there may be some evidence there i can also say as a longtime observer and admirer of the office of science and do we there's probably a lot of technology that you're doing that is attracting commercial interest do you find that to be the case pieces of this different kinds of reactions and materials and geometries and whatnot that could be used in totally different ways than you're using them here uh right i mean there just in the past two years there's been an incredible infusion of private money and to to startups you plot that versus time it's like yeah taking off but yeah to that point like there are many uh common problems between the different schemes uh like the first wall of the reactor in a magnetic um configuration if somebody solves that that's going to kind of help all the other schemes uh and sharing sharing technology like that that said we're out of time and thanks again for sharing this amazing story with us thanks very much chris thank you for having me