Summary of theory and simulation activities of ASIPP in A3 program

Under the support of A3 project, ASIPP has collaborated with NIFS to import MEGA code to fill in the blank of the energetic particles physics in the simulation platform. The Alfven eigenmodes and the fishbone modes driven by fast ions on EAST are simulated by this code. The physics research on LHW are studied within the support of A3 due to the characteristic LHW heating on EAST. The SOL current driven by LHW has been implemented in the BOUT++ simulations and is found to be able to broaden the SOL width, which makes the simulated scaling closer to the EAST measurements. For the understanding of the two LHWs injections on EAST, the nonlinear process between LHW and tokamak physics are simulated by GeFi. The generations of the high harmonic modes and sidebands through nonlinear mode-mode coupling are found to provide new power channels, and reduce the reflection significantly as the wave amplitude increases. The effects of perturbed orbits on the interactions of electrons with two LHWs resonant with electrons at different phase velocities shows that when the resonances of these two LHWs are overlapped sufficiently, the damping of the off-resonant wave and the oscillatory behavior of the wave amplitude are observed. A Flux Difference Splitting simulation capability for MHD systems based on a finite volume spatial discretization has been developed under A3 project. This code has been used to study the long time nonlinear dynamics of the coalescence instability. (author)