亚暴期间高纬黄昏—子夜扇区极光弧增亮与衰减及其与IMF的关系  

NIGHTSIDE AURORAL ARCS IN HIGH LATITUDES DURING SUBSTORMS AND THEIR RELATIONSHIP WITH IMF

作　　者：洪明华[1] 胡红桥 刘瑞源 汤克云[1] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100101 [2]中国极地研究所,上海200129

出　　处：《地球物理学报》2001年第1期12-23,共12页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目! (4963 4 1 60 ;4 9974 0 3 3 )

摘　　要：利用南极中山站极光全天空摄相、地磁、地磁脉动数据和Wind卫星的行星际磁场IMF观测数据 ,分析了 7个亚暴期间高纬黄昏—子夜扇区极光弧的短暂增亮现象 .极光弧特征是 ,短暂增亮随后很快衰减 ,历时 1 0— 2 0min ,基本沿着日 -地方向 ,有明显黄昏方向运动 .这些事件大都发生在IMFBz 南转之后 ,亚暴增长相或膨胀相期间 ,极光浪涌到达之前1 0— 73min消失 .相应的IMFBx>0 ,IMFBy<0 .这种极光弧和亚暴极光不同 ,它们与地磁活动及Pi2脉动不相关 .这 7个极光弧的形态和IMF特征表明 ,极光弧的增亮很可能由尾瓣重联产生 ,很快衰减归因于IMFBz 南向条件 ,而黄昏方向运动受IMFByObservations of all sky auroral imaging, geomagnetic field, Pi2 pulsation from Zhongshan Station and IMF data from Wind satellite have been used to investigate 7 cases of nightside auroral arcs intensification and fading in high latitudes. The characteristics of auroral arcs are as follows: All of arcs intensify briefly, and then fade lasting for 10—20min; the arcs nearly align along the Sun Earth direction with pronounced duskward drift; most of the arcs occur after the interplanetary magnetic field (IMF) turns southward corresponding to the substorm growth or expansion phase, and IMF B x >0, IMF B y <0; the dawn dusk drift of the arcs is in the opposite direction of IMF B y ; these arcs have no close relation to magnetic activities and Pi2 pulsation. The present results suggest that the brief intensification of auroral arcs may be due to IMF B x >0 which favors magnetic reconnection in the southern lobe of the magnetotail, the arc fading may be attributed to southward IMF B z , and the dawn dusk motion of the arcs may be driven by the effect of the IMF B y on the motion of the reconnection site. [

关 键 词：高纬极光弧 磁层亚暴 IMF 南级中山站 地磁脉动 观测数据 行星际磁场 

分 类 号：P318.2[天文地球—固体地球物理学]