Effect of temperature anisotropy on the dynamics of geodesic acoustic modes

Abstract

In this work, we revisit the linear gyro-kinetic theory of geodesic acoustic modes (GAMs) and derive a general dispersion relation for an arbitrary equilibrium distribution function of ions. A bi-Maxwellian distribution of ions is then used to study the effects of ion temperature anisotropy on GAM frequency and growth rate. We find that ion temperature anisotropy yields sensible modifications to both the GAM frequency and growth rate as both tend to increase with anisotropy and these results are strongly affected by the electron to ion temperature ratio.

References in corpus (3)

• Linear gyrokinetic investigation of the geodesic acoustic modes in realistic tokamak configurations
• Gyrokinetic modelling of anisotropic energetic particle driven instabilities in tokamak plasmas
• Gyrokinetic investigation of the nonlinear interaction of Alfvén instabilities and energetic-particle driven geodesic acoustic modes