SciDAC-Simulation of Energetic Particle Turbulence and Transport

In proposed burning plasma experiments such as the International Thermonuclear Experimental Reactor (ITER), fast ions and charged fusion products will constitute a significant fraction of local plasma energy density. For example, in the ITER baseline scenario, about 30% of the plasma energy density in the core will be due to energetic particles. Since such energetic populations often exist in states far away from thermal equilibrium due to their non-Maxwellian distribution and/or peaked pressure profiles at the core, they can readily tap the corresponding free energies and collectively excite electromagnetic instabilities to intensities much enhanced over the thermal values. This project will develop update simulation capabilities for such instabilities and the associated anomalous transport using gyrokinetic techniques, such as are used in the GTC (Gyrokinetic Toroidal Code) and GYRO (Gyrokinetic) codes. These update methods will allow a more consistent treatment of the meso-micro scale coupling present between the Alfven modes and the thermal plasma. It will also develop update methods for taking into account the effect of the three-dimensional magnetic field variations that are present in tokamaks from toroidal field ripple, other large scale MHD (Magnetohydrodynamic) instabilities, and RWM (Resistive Wall Mode) control coils on the Alfven mode structure and energetic particle transport.