Full Wave Simulations of Fast Wave Efficiency and Power Losses in the Scrape-off Layer of Tokamak Plasmas in Mid/high Harmonic and Minority Heating Regimes
Authors: N. Bertelli, E.F. Jaeger, J.C. Hosea, C.K. Phillips, L. Berry, P.T. Bonoli, S.P. Gerhardt, D. Green, B. LeBlanc, R.J. Perkins, C.M. Qin, R.I. Pinsker, R. Prater, P.M. Ryan, G. Taylor, E.J. Valeo, J.R. Wilson, J.C. Wright, X.J. Zhang
Abstract: Several experiments on different machines and in different fast wave (FW) heating regimes, such as hydrogen minority heating and high harmonic fast waves, have found strong interaction between radio-frequency (RF) waves and the scrape-off layer (SOL) region. This paper examines the propagation and the power loss in the SOL by using the full wave code AORSA, in which the edge plasma beyond the last closed flux surface (LCFS) is included in the solution domain and a collisional damping parameter is used as a proxy to represent the real, and most likely nonlinear, damping processes. 3D AORSA results for National Spherical Torus eXperiment (NSTX), where a full antenna spectrum is reconstructed, are shown confirming the same behavior found for a single toroidal mode results in Bertelli et al Nucl. Fusion, 54 083004, 2014, namely, a strong transition to higher SOL power losses (driven by the RF field) has been found when the FW cut-off is moved away from in front of the antenna by increasing the edge density.
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Submitted to: Nuclear Fusion
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Download PPPL-5095 (pdf 1.4 MB / 15pp)
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