Effects of the Second Harmonic on the GAM in Electron Scale Turbulence

Abstract

The effects higher order harmonics have been self-consistently included in the derivation of the electron branch of the electron Geodesic Acoustic Mode (el-GAM) in an Electron-Temperature-Gradient (ETG) turbulence background. The work is based on a two-fluid model including finite β-effects while retaining non-adiabatic ions. In solving the linear dispersion relation, it is found that the due to the coupling to the m = 2 mode the real frequency may be significantly altered and yield higher values.