Evolution of Ring Current Protons Induced by Electromagnetic Ion Cyclotron Waves  

作　　者：肖伏良 田天 陈良旭 苏振鹏 郑惠南 

机构地区：[1]School of Physics and Electronic Sciences, Changsha University of Science and Technology, Changsha 410004 [2]State Key Laboratory of Space Weather, Chinese Academy of Sciences, Beijing 100190 [3]School of Earth and Space Sciences, Peking University, Beijing 100871 [4]CAS Key Lab for Basic Plasma Science, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026

出　　处：《Chinese Physics Letters》2009年第11期254-257,共4页中国物理快报（英文版）

基　　金：Supported by the National Natural Science Foundation of China Grant Nos 40874076, 40774079, 40774078 and 40774077, the Special Fund for Public Welfare Industry （meteorology） GYHY200806024, and the Visiting Scholar Foundation of State Key Laboratory for Space Weather, Chinese Academy of Sciences.

摘　　要：We investigate the evolution of the phase space density （PSD） of ring current protons induced by electromagnetic ion cyclotron （EMIC） waves at the location L=3.5, calculate the diffusion coefficients in pitch angle and momentum, and solve the standard two-dimensional Fokker-Planck diffusion equation. The pitch angle diffusion coefficient is found to be larger than the momentum diffusion coefficient by a factor of about 103 or above at lower pitch angles. We show that EMIC waves can produce efficient pitch angle scattering of energetic （- 100 keV） protons, yielding a rapid decrement in PSD, typically by a factor of - 10 within a few hours, consistent with observational data. This result further supports previous findings that wave-particle interaction is responsible for the rapid ring current decay.We investigate the evolution of the phase space density （PSD） of ring current protons induced by electromagnetic ion cyclotron （EMIC） waves at the location L=3.5, calculate the diffusion coefficients in pitch angle and momentum, and solve the standard two-dimensional Fokker-Planck diffusion equation. The pitch angle diffusion coefficient is found to be larger than the momentum diffusion coefficient by a factor of about 103 or above at lower pitch angles. We show that EMIC waves can produce efficient pitch angle scattering of energetic （- 100 keV） protons, yielding a rapid decrement in PSD, typically by a factor of - 10 within a few hours, consistent with observational data. This result further supports previous findings that wave-particle interaction is responsible for the rapid ring current decay.

关 键 词：Chinese climate network complex systems small world community 

分 类 号：O441.3[理学—电磁学] TM912.2[理学—物理]