Two sunspots in mutual interaction revealed by supercomputer MHD simulations

Movie from the paper "Penumbral Structure and Outflows in Simulated Sunspots," M. Rempel, M. Schüssler, R. H. Cameron, M. Knölker, in Science Express, Published Online June 18, 2009.
Science DOI: http://dx.doi.org/10.1126/science.1173798

"Sunspots are concentrations of magnetic field on the visible solar surface that strongly affect the onvective energy transport in their interior and surroundings. The filamentary outer region (penumbrae) of sunspots show systematic radial outward flows along channels of nearly horizontal magnetic field. These flows were discovered 100 years ago and are present in all fully developed sunspots. Using a comprehensive numerical simulation of a sunspot pair, we show that penumbral structures with such outflows form when the average magnetic field inclination to the vertical exceeds about 45 degrees. The systematic outflows are a component of the convective flows that provide the upward energy transport and result from anisotropy introduced by the presence of the inclined magnetic field."

The 3D simulation has required supercomputing at 76 trillion calculations per second. To create the model, the research team designed a virtual, three-dimensional domain that simulates an area on the Sun measuring about 31,000 miles by 62,000 miles and about 3,700 miles in depth - an expanse as long as eight times Earth's diameter and as deep as Earth's radius. The scientists then used a series of equations involving fundamental physical laws of energy transfer, fluid dynamics, magnetic induction and feedback, and other phenomena to simulate sunspot dynamics at 1.8 billion points within the virtual expanse, each spaced about 10 to 20 miles apart. For weeks, they solved the equations on NCAR's new bluefire supercomputer, an IBM machine that can perform 76 trillion calculations per second. (http://www.spaceref.com/news/viewpr.html?pid=28491)

Category:

Science & Technology

Tags:

• astrophysics
• solar physics
• sunspots
• mhd
• 3D

[Zolastouch1]

well...