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Comparison of ICRF-Induced Ion Diffusion Coefficients Calculated with the DC and AORSA Codes

Journal Article · · AIP Conference Proceedings
DOI:https://doi.org/10.1063/1.3273818· OSTI ID:21335794
;  [1]; ; ;  [2]; ;  [3]
  1. CompX, P.O. Box 2672, Del Mar, CA 92014-5672 (United States)
  2. Oak Ridge National Laboratory, Oak Ridge (United States)
  3. MIT Plasma Science and Fusion Center, Cambridge (United States)
The DC (Diffusion Coefficient) code obtains RF diffusion coefficients by direct numerical integration of the Lorentz force equation for ion motion in the combined equilibrium fields and the RF full wave EM fields from the AORSA full-wave code. Suitable averaging over initial gyro- and toroidal-angle of coordinate 'kicks' after a bounce-period, gives noise-free bounce-averaged diffusion coefficients. For direct comparison with zero-banana-width coefficients from AORSA, perpendicular-drift terms in the Lorentz equation are subtracted off the integration. The DC code has been coupled to the CQL3D Fokker-Planck code. For a C-Mod minority ion ICRF heating test case, the total power absorption using the diffusion coefficients agree well, and the profiles are similarly close. This supports the DC calculation and the Kennel-Engelmann-based, no-correlations, coefficient calculation in AORSA. However, resonance correlations cause large differences in the pitch angle variations of the diffusion coefficients, and in the resulting evolution of the ion distribution functions.
OSTI ID:
21335794
Journal Information:
AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 1187; ISSN APCPCS; ISSN 0094-243X
Country of Publication:
United States
Language:
English