Effects of Spatial Variation of Thermal Electrons on Whistler-Mode Waves in Magnetosphere  

作　　者：陈伦锦 郑惠南 肖伏良 王水 

机构地区：[1]CAS Key Laboratory for Basic Plasma Physics, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026 [2]Department of Physics and Electronic Sciences, Changsha University of Science and Technology, Changsha 410076

出　　处：《Chinese Physics Letters》2006年第9期2613-2616,共4页中国物理快报（英文版）

基　　金：Supported by the National Natural Science Foundation of China under Grant Nos 40336052 and 40474064.

摘　　要：A ray-tracing method is developed to evaluate the wave growth/damping and specifically propagation trajectories of the magnetospherically reflected Whistler-mode waves. The methodology is valid for weak wave growth/damping when plasma is comprised of a cold electron population and a hot electron population, together with background neutralizing ions, e.g. protons. The effect of anisotropic thermal electrons on the propagation of Whistler-mode waves is studied in detail. Numerical results are obtained for a realistic spatial variation model of plasma population, including the cold electron density distribution, and the thermal electron density and temperature distribution. It is found that, analogous to the case of the typical cold plasma approximation, the overall ray path of Whistler-mode waves is insensitive to the thermal electron density and temperature anisotropy, and the ray path reflects where wave frequency is below or comparable to the local lower hybrid resonance frequency flhr. However, the wave growth is expected to be influenced by the thermal electron population. The results present a first detailed verification for the validity of the typical cold plasma approximation for the propagation of Whistler-mode waves and may account for the observation that the Whistler-mode waves tend to propagate on a particular magnetic shell L where the wave frequency is comparable to fthe.A ray-tracing method is developed to evaluate the wave growth/damping and specifically propagation trajectories of the magnetospherically reflected Whistler-mode waves. The methodology is valid for weak wave growth/damping when plasma is comprised of a cold electron population and a hot electron population, together with background neutralizing ions, e.g. protons. The effect of anisotropic thermal electrons on the propagation of Whistler-mode waves is studied in detail. Numerical results are obtained for a realistic spatial variation model of plasma population, including the cold electron density distribution, and the thermal electron density and temperature distribution. It is found that, analogous to the case of the typical cold plasma approximation, the overall ray path of Whistler-mode waves is insensitive to the thermal electron density and temperature anisotropy, and the ray path reflects where wave frequency is below or comparable to the local lower hybrid resonance frequency flhr. However, the wave growth is expected to be influenced by the thermal electron population. The results present a first detailed verification for the validity of the typical cold plasma approximation for the propagation of Whistler-mode waves and may account for the observation that the Whistler-mode waves tend to propagate on a particular magnetic shell L where the wave frequency is comparable to fthe.

关 键 词：REFLECTED WHISTLERS PLASMA ANISOTROPY RADIATION DENSITY FIELD 

分 类 号：TN201[电子电信—物理电子学]