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Title: Efficient Generation of Non-Inductive, Off-axis, Ohkawa Current, Driven by Electron Bernstein Waves in High Beta, Spherical Torus Plasmas

Technical Report ·
DOI:https://doi.org/10.2172/827839· OSTI ID:827839

Off-axis rf-driven current can play a critical role in sustaining high Beta spherical torus (ST) plasmas without a central solenoid. Numerical modeling of electron Bernstein wave current drive (EBWCD) for a {Beta} {approx} 40% ST plasma predicts efficient, off-axis, Ohkawa EBWCD. Current can be efficiently driven at r/a greater than 0.5 where the large trapped electron fraction precludes conventional Fisch-Boozer current drive and provides near-ideal conditions for Ohkawa EBWCD. Also, Ohkawa EBWCD efficiency increases with r/a. Enhancement over Fisch-Boozer current drive is a factor of two at r/a {approx} 0.2 rising to over an order of magnitude at r/a {approx} 0.5.

Research Organization:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Organization:
USDOE Office of Science (SC) (US)
DOE Contract Number:
AC02-76CH03073
OSTI ID:
827839
Report Number(s):
PPPL-3943; TRN: US0403712
Resource Relation:
Other Information: PBD: 26 Apr 2004
Country of Publication:
United States
Language:
English