Open AccessElectron Bernstein Wave Research on NSTX and CDX-U
Author(s) -
G. Taylor,
P.C. Efthimion,
Brant Jones,
G. L. Bell,
A. Bers,
T.S. Bigelow,
M.D. Carter,
Richard Harvey,
A.K. Ram,
D.A. Rasmussen,
A. P. Smirnov,
J.B. Wilgen,
J. Wilson
Publication year - 2003
Publication title -
osti oai (u.s. department of energy office of scientific and technical information)
Language(s) - English
Resource type - Reports
DOI - 10.2172/814023
Subject(s) - electron , plasma , limiter , atomic physics , physics , computational physics , tokamak , electron temperature , radiation , optics , nuclear physics , electrical engineering , engineering
Studies of thermally emitted electron Bernstein waves (EBWs) on CDX-U and NSTX, via mode conversion (MC) to electromagnetic radiation, support the use of EBWs to measure the Te profile and provide local electron heating and current drive (CD) in overdense spherical torus plasmas. An X-mode antenna with radially adjustable limiters successfully controlled EBW MC on CDX-U and enhanced MC efficiency to {approx} 100%. So far the X-mode MC efficiency on NSTX has been increased by a similar technique to 40-50% and future experiments are focused on achieving * 80% MC. MC efficiencies on both machines agree well with theoretical predictions. Ray tracing and Fokker-Planck modeling for NSTX equilibria are being conducted to support the design of a 3 MW, 15 GHz EBW heating and CD system for NSTX to assist non-inductive plasma startup, current ramp up, and to provide local electron heating and CD in high beta NSTX plasmas
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