Kinetic Alfvén wave instability driven by electron temperature anisotropy in high-β plasmas

Abstract

Based on the kinetic dispersion equation in the low-frequency condition of ω<Ωi (the ion cyclotron frequency), the instability driven by the electron temperature anisotropy in high-β plasmas, which is associated with kinetic Alfvén waves in the wave vector range of k∥λI⪡1 and k⊥ρi⪡1 (where λI and ρi are the ion inertial length and gyroradius, respectively), is investigated. The results show that the structures of both the growth rate and the real frequency are different from those driven by the ion temperature anisotropy. The growth rate is larger than that driven by the ion anisotropy. The critical instability condition is modified dramatically, in which the electron driven growth rate does not vanish at the classical critical point and its deviation from zero increases with the kinetic effect due to the short-wavelength modification.