Using AORSA to simulate helicon waves in DIIID and ITER

Recent efforts by Vdovin [1] and Prater [2] have shown that helicon waves (fast waves at ~30 ion cyclotron frequency harmonic) may be an attractive option for driving efficient off-axis current drive during non-inductive tokamak operation for DIIID, ITER and DEMO. For DIIID scenarios, the ray tracing code GENRAY has been extensively used to study helicon current drive efficiency and location as a function many plasma parameters. has some limitations on absorption at high cyclotron harmonics, so the full wave code AORSA, which is applicable to arbitrary Larmor radius and can therefore resolve high ion cyclotron harmonics, has been recently used to validate the GENRAY model. It will be shown that the GENRAY and AORSA driven current drive profiles are comparable for the envisioned high temperature and density advanced scenarios for DIIID, where there is high single pass absorption due to electron Landau damping. AORSA results will be shown for various plasma parameters for DIIID and for ITER. Computational difficulties in achieving these AORSA results will also be discussed. * Work supported by USDOE Contract No. DE-AC05-00OR22725 [1] V. L. Vdovin, Plasma Physics Reports, V.39, No.2, 2013 [2] R. Prater et al, Nucl. Fusion, 52, 083024, 2014