One-dimensional full-wave description of plasma emission and absorption in the ion cyclotron range of frequency in tokamaks

摘要

To maintain the ignition state in a tokamak fusion reactor, a control must be performed on the population of alpha-products, and this implies the ability to diagnose those alpha-particles. It is studied here whether the detection of emission radiated in the ion cyclotron range of frequency by a reactor plasma can provide useful information concerning fusion products, especially concerning their density profile. It is shown that the detection of the radiation emitted by the fast alpha particules along their cyclotron motion can give access to moments of their distribution function. This requires one to compute the phase of the emitted field, using a full-wave approach. Such a technique allows one to set in a convenient way the inverse problem of the determination of the emitting alpha-particles distribution through the radiation detection. A brief analysis of the expected situation in a reactor-relevant plasma is given. In parallel, the one-dimensional full-wave code developed in this frame is also useful for studying the physics of fast wave plasma heating. It enables one to take into account the mode conversion of the fast wave into the ion Bernstein wave that appears near each ion cyclotron resonance. Results show that higher order terms may significantly alter the energy partitioning, in hot plasma cases involving mode conversion heating and/or ion cyclotron high harmonics heating. (C) 1999 American Institute of Physics. [S1070-664X(99)03406-0]. [References: 50]