Theory of magnetohydrodynamic instabilities excited by energetic particles in tokamaks

来自 AIP

阅读量：

作者：

展开

摘要：

The resonant excitations of high‐n magnetohydrodynamic (MHD) instabilities by the energetic ions/alpha particles in tokamaks are theoretically analyzed. Here, n is the toroidal mode number. Since, typically, the MHD modes consist of two‐scale structures; one singular (''inertial'') region and one regular (ideal) region, the energetic particle contributions in the singular region are suppressed by the finite‐size orbits. Analytical dispersion relations can then be derived via the asymptotic matching analysis. The dispersion relations have the generic form of the ''fishbone'' dispersion relation and demonstrate, in particular, the existence of two types of modes; that is, the MHD gap mode and the energetic‐particle continuum mode. Specific expressions are given for both the kinetic ballooning modes (KBM) and the toroidal Alfvén modes (TAM). It is suggested that the stability property may be qualitatively regarded as the ''hybrid'' of conventional MHD tokamaks and field reversed ion rings.

展开

关键词：

Magnetohydrodynamics Dispersion relations Tokamaks Alpha particles Instability analysis

DOI：

10.1063/1.46548

被引量：

174

年份：

1994