Ionospheric Feedback Instability in the Coupling of Magnetosphere—Ionosphere

作     者：王旭宇 曹晋滨 

作者机构：LaboratoryofSpaceWeatherCenterforSpaceScienceandAppliedResearchChineseAcademyofSciencesBeijing100080 hysikalisckesInstitutUniversityofBernBernCH-3012Switzerland LaboratoryofSpaceWeatherCenterforSpaceScienceandAppliedResearchChineseAcademyofSciencesBeijing100080 

出 版 物：《Chinese Physics Letters》 (中国物理快报（英文版）)

年 卷 期：2003年第20卷第8期

页      面：1401-1404页

核心收录：

学科分类：07[理学] 070601[理学-气象学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0706[理学-大气科学] 0704[理学-天文学] 

基　　金：国家自然科学基金 瑞士国家自然科学基金 

主　　题：ionospheres N conductivity J(Joule) Free energy magnetospheres Feedback ionization conductivity Energy sources ionospheric conductivity Earth magnetosphere planetary magnetospheres 

摘      要：The ionospheric feedback instability is discussed by using the conductivity argument. We give an exact quantitative description to show that the free energy for this instability comes from the reduction of the Joule dissipation produced by the pre-existing convection electric field through self-consistent changes in ionization and conductivity due to Alfvenic perturbations in the ionosphere. By the over-reflection of Alfven waves, the energy in the active ionosphere is pumped into the magnetosphere, which is contrary to the usual case whereby energy carried by Afven waves is deposited in the ionosphere by Joule dissipation. The ionospheric feedback enhances the electron E * B drift. The electron conductivity is controlled by the ion Perdersen conductivity rather than by the electrons Pedersen conductivity. We also provide a qualitative theoretical explanation to the intense aurora favoured by a lower ambient ionospheric conductivity in the ionospheric feedback instability.