<RESEARCH REPORT>Resonance Absorption of ICRF Wave in Edge Plasma

概要

論文の詳細を見る
An edge plasma is shown to significantly absorb ICRF wave when a resonant triplet, a cutoff-resonance-cutoff triplet, is constructed in the evanescent region. Two-ion-component plasmas in a torus are considered though the plasmas are modeled by a slab in which the density changes linearly along the x-axis. The resonance is a perpendicular-ion-cyclotron resonance, i. e., an Alfven resonance, and is formed when the applied frequency ω is smaller than the local cyclotron frequency, at the edge of the antenna side, of the lighter species of ions. Roughly the absorption rate A_b is given by M^2 for M^2 >> S^2 and S^4 for S^2 >> M^2 where M = K_yl and S ≅ K_zl and l is a scale length of the order of the plasma minor radius and K_y and K_z are the perpendicular and the parallel components of the wave vector. It is noted that the both quantities, M and S, readily become of the order of unity. Since A_b is not very sensitive to the density ratio of the two ion species, a few percent of impurities may cause a significant absorption. As the mass ratio of the two ion species comes close to unity the triplet forms readily. Therefore a D-T plasma seems to suffer more easily this kind of resonance absorption than a D-H plasma.
核融合科学研究所の論文