Properties of Whistler Waves in Warm Electron Plasmas

Abstract

Dispersion relation and electromagnetic properties of obliquely propagating whistler waves are investigated on the basis of a warm electron fluid model. The magnetic field of whistler waves is nearly circularly polarized with respect to the wave vector in a plasma where the electron plasma frequency is much larger than the electron cyclotron frequency , and the magnetic field polarization can become elliptical, or even linear, polarization as . In the plasmas with , the resonant frequency is about , which is different from predicted by the cold electron fluid model. Near the resonant frequency, the whistler wave approximates a quasi-magnetostatic mode, not a quasi-electrostatic mode in the cold electron plasmas. Moreover, the detailed mode properties are given in Earth’s magnetosphere, the solar active region, and Jupiter’s polar cap. Furthermore, the study proposes that the ratio of the electrostatic to electromagnetic component of the electric field can be used to distinguish the whistler mode from the Z-mode in the frequency range of in the solar active region and Jupiter’s polar cap.