The mid-high latitude whistler mode chorus waves observed around substorm onsets  

作　　者：YANG JunYing CAO JinBin YAN ChunXiao LI LiuYuan MA YuDuan 

机构地区：[1]Key Laboratory of Space Weather,Center for Space Science and Applied Research,Chinese Academy of Sciences,Beijing 100080,China [2]Graduate University of Chinese Academy of Sciences,Beijing 100039,China

出　　处：《Science China(Technological Sciences)》2008年第10期1648-1658,共11页中国科学（技术科学英文版）

基　　金：the National Natural Science Foundation of China (Grant Nos. 40621003, 40523006, 40704028, 40604018);973 Program of China (Grant No. 2006CB806305);the Specialized Research Fund for State Key Laboratories of China.

摘　　要：Using the data of LFEW/TC-2, we studied the dawn side chorus around substorm onsets during a strong geomagnetic storm in November 2004. During this storm, LFEW/TC-2 observed 14 dawnside chorus events. Nine of them were associated with substorms and occurred within 40 min around the substorm onsets. The fre-quencies of waves have a very good correlation with the half equatorial electron cyclotron frequencies. Chorus can be excited in the region near magnetic equato-rial plane and then propagate to the mid and high latitudes. When the wave fre-quencies reach the local lower hybrid frequencies, chorus can be reflected due to the lower hybrid resonance. The time delay between the chorus and its echo is about 28 min. Previous observations show that the chorus can propagate at most to the magnetic latitudes of 40°. LFEW/ TC-2 found for the first time that the chorus in space could propagate to the magnetic latitude of 70°. Since most of the previous chorus observations are made close to the magnetic equatorial plane, our results are important for the studies of excitation and propagation of whistler mode wave, and relevant relativistic electron acceleration in the magnetosphere.Using the data of LFEW/TC-2, we studied the dawn side chorus around substorm onsets during a strong geomagnetic storm in November 2004. During this storm, LFEW/TC-2 observed 14 dawnside chorus events. Nine of them were associated with substorms and occurred within 40 min around the substorm onsets. The frequencies of waves have a very good correlation with the half equatorial electron cyclotron frequencies. Chorus can be excited in the region near magnetic equatorial plane and then propagate to the mid and high latitudes. When the wave frequencies reach the local lower hybrid frequencies, chorus can be reflected due to the lower hybrid resonance. The time delay between the chorus and its echo is about 28 min. Previous observations show that the chorus can propagate at most to the magnetic latitudes of 40°. LFEW/ TC-2 found for the first time that the chorus in space could propagate to the magnetic latitude of 70°. Since most of the previous chorus observations are made close to the magnetic equatorial plane, our results are important for the studies of excitation and propagation of whistler mode wave, and relevant relativistic electron acceleration in the magnetosphere.

关 键 词：CHORUS SUBSTORM ONSET electron acceleration 

分 类 号：P353[天文地球—空间物理学]