Electron Bernstein Wave Simulation Using FullWave Local Implicit Solver

To simulate hot plasma effects on radio-frequency (RF) wave propagation in tokamaks, a preliminary hot plasma model with realistic non-local conductivity kernels in configuration space has been implemented in the hybrid solver [1, 2] of the 2D FullWave code. The time evolution of full wave equations uses a semi-explicit method where the electric wave fields are solved locally and implicitly, while the magnetic fields are solved explicitly. The plasma current at each point is calculated by integrating non-local contributions from neighboring regions. The solution is relaxed toward the steady-state wave solution in the frequency domain using a steepest descent method. Convergence is achieved by repeatedly alternating between time-evolution and relaxation steps. The accuracy of this new hybrid solver with hot model is benchmarked and validated against a direct solver by tests with coarse grids.

The updated FullWave code is applied to simulate Electron Bernstein Waves (EBW) in spherical tokamak (ST) configurations. The non-local conductivity kernels are calculated in 2D configuration space via particle tracking [3, 4] on a coarse grid and then interpolated onto the main computational grid. We have applied non-local hot model to simulate ECRH on VEST at SNU[5] and an analytical ST plasma. The simulated wave structure, calculated with sufficient resolution, shows excellent agreement with predictions. Details of the non-local hybrid model's algorithm and the full simulation results will be presented.