ICRF mode conversion in three-ion species heating experiment and in flow drive experiment on the Alcator C-Mod tokamak

Y. Lin; S.J. Wukitch; E. Edlund; P. Ennever; A. E. Hubbard; M. Porkolab; J. Rice; J. Wright

doi:10.1051/epjconf/201715703030

Proceedings

Open Access

EPJ Web of Conferences 157, 03030 (2017)
https://doi.org/10.1051/epjconf/201715703030

ICRF mode conversion in three-ion species heating experiment and in flow drive experiment on the Alcator C-Mod tokamak

Y. Lin^*, S.J. Wukitch, E. Edlund, P. Ennever, A. E. Hubbard, M. Porkolab, J. Rice and J. Wright

MIT Plasma Science and Fusion Center, Cambridge, MA, USA

^* Corresponding author: ylin@psfc.mit.edu

Published online: 23 October 2017

Abstract

In recent three-ion species (majority D and H plus a trace level of ³He) ICRF heating experiments on Alcator C-Mod, double mode conversion on both sides of the ³He cyclotron resonance has been observed using the phase contrast imaging (PCI) system. The MC locations are used to estimate the species concentrations in the plasma. Simulation using TORIC shows that with the ³He level <1%, most RF power is absorbed by the ³He ions and the process can generate energetic ³He ions. In mode conversion (MC) flow drive experiment in D(³He) plasma at 8 T, MC waves were also monitored by PCI. The MC ion cyclotron wave (ICW) amplitude and wavenumber k_R have been found to correlate with the flow drive force. The MC efficiency, wave-number k of the MC ICW and their dependence on plasma parameters like T_e0 have been studied. Based on the experimental observation and numerical study of the dispersion solutions, a hypothesis of the flow drive mechanism has been proposed.

© The authors, published by EDP Sciences, 2017

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