DIII-D Tokamak at General Atomic

Plasma science (the study of ionized gases) is critical to the development of fusion energy (involving the fusion of nuclei), which could be an abundant energy source in the future. To produce practical amounts of fusion power, plasmas need to be confined at high pressure in a stable condition. Research supported by the Office of Science led to the development and verification of magnetohydrodynamic (MHD) stability theory, which predicts plasma instabilities that limit the stable operating range of devices that confine plasmas using magnetic fields. MHD instabilities can affect magnetic field configurations and cause rapid losses of plasma energy and particles. Using large computer codes, fusion scientists developed MHD stability theory to the point where it can determine plasma stability limits in complex magnetic configurations. Experiments to verify the quantitative predictions spanned two decades because they required the development of new techniques to form and control complex plasma shapes, high-power heating sources to increase plasma pressure, and novel diagnostics for measuring the spatial distributions of plasma pressure and current. Staff at General Atomics, a DOE contractor, received the American Physical Society Award for Excellence in Plasma Physics Research in 1994 for verifying the predicted stability limits of high-pressure plasmas.

Scientific Impact: This work established a solid theoretical foundation for evaluating the stable operating potential of attractive plasma confinement devices, such as tokamaks. Such advances often prove useful in other fields of research that use plasma science and technology, from solar and magnetospheric physics to materials science.

Social Impact: This work will help promote the availability of fusion as an inexhaustible, safe, and environmentally attractive energy source. In addition to the general public, beneficiaries may include industries that use plasma science and technology, including makers of semiconductors and space propulsion systems.

"Reference: Higher Beta at Higher Elongation in the DIII-D Tokamak," E. A. Lazarus, M. S. Chu, J. R. Ferron, F. J. Helton, Rev. Mod. Phys. 59, 175 (1987)

"An Optimization of Beta in the DIII-D Tokamak," E. A. Lazarus, L. L. Lao, T. H. Osborne, T. S. Taylor, Phys. Fluids B 4, 3644 (1992)

URL: http://fusion.gat.com/diii-d/

Technical Contact: Erol Oktay, Research Division, 301-903-4928

Press Contact: Jeff Sherwood, DOE Office of Public Affairs, 202-586-5806

SC-Funding Office: Office of Fusion Energy Sciences