GA-Theory Collaboration with NSTX-U

The National Spherical Torus Experiment-Upgrade (NSTX-U) is a fusion energy experiment operated by the Princeton Plasma Physics Laboratory. It has a spherical torus (ST) shaped magnetic field to confine a hydrogen plasma heated to temperatures needed for a fusion reaction to take place. The ST is the most compact form of a tokamak confinement configuration that is shaped like a donut. An ST has a very small hole in its middle compared to a tokamak. The General Atomics Theory and Computational Science group (GA-Theory) has a long history of theoretical and numerical modeling of magnetically confined hot plasmas stretching back to the beginning of fusion energy research. General Atomics is the operator of the DIII-D National Fusion Facility that has hosted the DIII-D tokamak experiment in the United States since 1987. The GA-Theory group has played the important role of developing theoretical codes and models of the stability and turbulence of hot tokamak plasmas and validating these models with measurements on DIII-D. This proposal is for GA-Theory to join the NSTX-U research collaboration for four years. The proposed research will be a cooperative activity with NSTX-U staff to validate the GA-Theory codes in the compact geometry of the ST. This will help achieve milestones of the approved NSTX-U research plan. The ST geometry is predicted by theory to change the plasma turbulence and stability in ways that cannot be explored in a tokamak. The range of experimental testing of the GA-Theory codes will be expanded to ST geometry. Theoretical predictions will help find the optimum performance regimes of NSTX-U and potentially new non-linear plasma confinement states could be discovered.