Recent Results from the SciDAC Partnership for Simulation of Fusion Relevant RF Actuators*

We present an overview of research related to predicting the behavior of the plasma boundary region in the response to applied radio frequency (RF) power in the ion-cyclotron and lower-hybrid range of frequencies. We focus on the production of impurities via RF sheath enhancement and the non-linear, multi-timescale response of the scrape-off-layer plasma to RF power. Particular results include: (i) a successful multi-implementation benchmarking of the non-linear fluid RF sheath boundary condition, additional verification of that fluid condition with fully-kinetic calculations of the same, and estimates of impurity sputtering as a result for simple geometries; (ii) calculations of the RF ponderomotive force driving terms in full high fidelity 3D geometry in front of an ICRF antenna and initial estimates which show that force as a significant source on density transport; (iii) benchmarking of the combined use of high-order finite-elements with field-aligned meshes towards a new far-scrape-off-layer fluid transport simulation capability; and (iv) demonstrated progress on the effective preconditioning of iterative solvers for the frequency-domain Maxwell equations for larger degree-of-freedom, high geometric-fidelity simulations.