Effects of non-maxwellian species on ion cyclotron waves propagation and absorption in magnetically confined plasmas
Magnetically confined plasmas can contain significant concentrations of nonthermal particles, arising from neutral beam injection, fusion reactions, shock heating, or wave-driven acceleration of resonant plasma species. The associated distribution functions can depart significantly from Maxwellians, which may impact the propagation and absorption of radio frequency waves. The potential effect of these particles has been investigated using a full-wave code that has been extended to handle gyrotropic, but otherwise arbitrary distribution functions. This code has been used to numerically simulate ion cyclotron resonance heating sICRHd in magnetic fusion plasmas in which coresonant neutral beam injection sNBId heating may also be applied. The presence of nonthermal ion populations generated by the NBI can alter the ICRH characteristics. Two situations involving ion cyclotron range of frequency waves are presented: fast wave to ion Bernstein wave mode conversion and high harmonic fast wave electron heating. In both cases, the adequacy of an equivalent Maxwellian-based description is discussed. Results indicate that the absorption profiles are more strongly affected than the wave fields by the presence of nonthermal species.
Bibliographic Reference: An article published in: Physics of Plasmas, Vol. 12 (2005), p.1-10
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Record Number: 200518070 / Last updated on: 2005-04-19
Original language: en
Available languages: en