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Theory and Computational Sciences
The mission of the Theory group at General Atomics is:
- to perform fundamental theoretical research in the theory of fusion plasmas
- to provide theoretical support to the DIII-D National Fusion Facility
- to facilitate scientific discovery in fusion research through the application of advanced computer science techniques.
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Fusion is potentially an inexhaustible energy source whose exploitation requires basic understanding of high-temperature plasmas. The development of a science-based predictive capability for fusion-relevant plasmas is a challenge central to fusion energy science, in which numerical modeling has played a vital role for more than four decades.
The program in Theory and Simulation of Fusion Plasmas at General Atomics supports the DOE's goals of advancing fundamental understanding of plasmas, resolving outstanding scientific issues and establishing reduced-cost paths to more attractive fusion energy systems, and advancing understanding and innovation in high-performance plasmas including burning plasmas.
The program in advanced computer science techniques supports the same goal through the application of a wide variety of technologies including Grid Computing, Parallel Computing, Advanced Collaborative Environments, Large-Scale Data Management, Scientific Visualization, and Tiled Display Walls.
Announcements
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Weekly Highlights
Numerical experiments quantifying the role of both 'residual' Rosenbluth-Hinton zonal flows and geodesic acoustic modes (GAMs) in saturating drift-wave turbulence have revealed several key findings. The GAMs can represent an important source of shear stabilization, as they can be excited to sufficiently strong levels to counter-act the reduced 'per-unit' shearing efficiency due to their finite frequency. Also, the ExB component of the zonal flow shear is stabilizing for finite-n drift-waves, while the diamagnetic component appears to destabilize the finite-n modes, and that the entropy generation peaks at wavelengths corresponding to peak transport production, but entropy dissipation is spread broadly over many wave numbers (including the n=0 zonal modes). These results appear to hold for ITG, TEM and mixed ITG/TEM turbulence. The results have been published in the December 2008 issue of Physics of Plasmas.
C. Holland gave a seminar on validation and high performance computing in fusion plasmas at the Fermilab weekly colloquium on Wednesday, Dec. 17. A video of the seminar will be made available on the Fermilab website.
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