Investigation of RF-enhanced plasma potentials on Alcator C-Mod
Author(s)Cziegler, I.; Myra, J.; Ochoukov, Roman Igorevitch; Whyte, Dennis G.; Brunner, Daniel Frederic; Labombard, Brian; Lipschultz, Bruce; Terry, James L.; Wukitch, Stephen James; ... Show more Show less
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Radio frequency (RF) sheath rectification is a leading mechanism suspected of causing anomalously high erosion of plasma facing materials in RF-heated plasmas on Alcator C-Mod. An extensive experimental survey of the plasma potential (Φ[subscript P]) in RF-heated discharges on C-Mod reveals that significant Φ[subscript P] enhancement (>100 V) is found on outboard limiter surfaces, both mapped and not mapped to active RF antennas. Surfaces that magnetically map to active RF antennas show Φ[subscript P] enhancement that is, in part, consistent with the recently proposed slow wave rectification mechanism. Surfaces that do not map to active RF antennas also experience significant Φ[subscript P] enhancement, which strongly correlates with the local fast wave intensity. In this case, fast wave rectification is a leading candidate mechanism responsible for the observed enhancement.
DepartmentMassachusetts Institute of Technology. Department of Nuclear Science and Engineering; Massachusetts Institute of Technology. Plasma Science and Fusion Center
Journal of Nuclear Materials
Ochoukov, R., D.G. Whyte, D. Brunner, I. Cziegler, B. LaBombard, B. Lipschultz, J. Myra, J. Terry, and S. Wukitch. “Investigation of RF-Enhanced Plasma Potentials on Alcator C-Mod.” Journal of Nuclear Materials 438 (July 2013): S875–S878.
Author's final manuscript