Abstract
A review of fast electron dynamic studies in the tokamaks TS, JET, and ASDEX during lower hybrid current drive is presented. In almost all experiments, the collisional slowing down is predominant, so a straightforward assessment of the fast electron radial transport is difficult, especially for large size tokamaks. From recent LH power modulation experiments performed on TS at low density, the fast electron diffusion coefficient, Dst, is found between 0.1-0.3m2s-1, close to the value determined on ASDEX in similar plasma conditions. An estimate of Dst is also obtained in TS and JET by modeling the plasma dynamics, using ray-tracing+Fokker-Planck codes. For JET, the fast electron transport is fully taken into account in the Fokker-Planck equation. Despite some quantitative discrepancies between Dst values determined from different methods, the diffusion rate of the fast electrons is weak enough for current profile control scenarii to be relevant on large tokamaks. A determination of the type of the turbulence - electrostatic or magnetic - that could drive the radial transport of fast electrons requires finer LH experiments.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
