Diem SJ, Taylor G, Caughman JB, Efthimion PC, Kugel H, LeBlanc BP, Phillips CK, Preinhaelter J, Sabbagh SA, Urban J. Collisional damping of electron bernstein waves and its mitigation by evaporated lithium conditioning in spherical-tokamak plasmas.
PHYSICAL REVIEW LETTERS 2009;
103:015002. [PMID:
19659154 DOI:
10.1103/physrevlett.103.015002]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Indexed: 05/28/2023]
Abstract
The first experimental verification of electron Bernstein wave (EBW) collisional damping, and its mitigation by evaporated Li conditioning, in an overdense spherical-tokamak plasma has been observed in the National Spherical Torus Experiment (NSTX). Initial measurements of EBW emission, coupled from NSTX plasmas via double-mode conversion to O-mode waves, exhibited <10% transmission efficiencies. Simulations show 80% of the EBW energy is dissipated by collisions in the edge plasma. Li conditioning reduced the edge collision frequency by a factor of 3 and increased the fundamental EBW transmission to 60%.
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