Finite-Element Solution of a Vorticity Transport Model Including RF Antenna Effects and Application to Scrape-Off-Layer-Turbulence Simulations

Radio-frequency (RF) heating and current drive are important for magnetic fusion devices. The associated antenna structures can result in large rectified sheath potentials and ponderomotive forces, which can drive large plasma flows. These flows can drive or suppress turbulence in the scrape-off layer (SOL), which can significantly affect the RF-wave coupling to and propagation through the plasma. To model these plasma flows with the complicated (material) boundary shapes and boundary conditions needed, a drift-reduced fluid-plasma model has been implemented in the the COMSOL Multiphysics finite-element (FEM) package, and in the more scalable Modular Finite-Element (MFEM) package. Steady-state solutions have been obtained with model RF-antenna-structure boundaries and RF-sheath boundary conditions, so far in a simplified two-dimensional, axisymmetric geometry. The values of the potential on a flux surface contained in the FEM simulation domain can be used as boundary conditions in turbulence codes such as the BOUT++-based code SOLT3D. Progress on the generalizing the FEM-based implementations to complicated three-dimensional domains and boundary conditions, model ponderomotive sources, and comparison against and coupling with relevant BOUT++ codes will also be reported.