Nightside field-aligned current during the April 6,2000 superstorm  

作　　者：WANG Yuan HONG MingHua CHEN GengXiong XU WenYao DU AiMin ZHAO XuDong LIU XiaoCan LUO Hao 

机构地区：[1]Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China [2]Graduate University of Chinese Academy of Sciences, Beijing 100049, China [3]State Key Laboratory of Space Weather, Beijing 100190, China [4]Institute of Geophysics, China Earthquake Administration, Beijing 100081, China

出　　处：《Chinese Science Bulletin》2010年第20期2175-2181,共7页

基　　金：supported by the National Basic Research Program of China(2006CB806305);the National Natural Science Foundation of China(40874088 and 40890163);the Special Fund for Public Welfare Industry(GYHY200806072);State-level Public Welfar Scientific Research Ccourtyard Basic Scentific Research Operation Cost(058904)

摘　　要：Using the east-west geomagnetic disturbance fields observed from stations at mid-latitudes,we investigate the characteristics of field-aligned currents on the nightside during the April 6,2000 superstorm.The results indicate that there is an eastward disturbance on the nightside of Northern Hemisphere during the main phase of magnetic storm,while the interplanetary magnetic field(IMF)is continued southward.The positive disturbances in the postmidnight are larger than that in the premidnight.This suggests that upward field-aligned currents develop on the nightside,when the IMF is directed southward.The peak of upward fieldaligned currents is located in postmidnight,and it will be more obvious at substorm expansion.We get the conclusion that both partial ring current and region-2 field-aligned current shift to dusk sector.The upward region-2 current is decreased at substorm onset,and intensified after it.We also investigate the relationship between the upward field-aligned currents on the nightside and the auroral electrojets at high latitudes.It shows a good correspondence between region-2 current and the westward electrojet in the postmidnight.We suppose that they are both associated with the convection electric field.Using the east-west geomagnetic disturbance fields observed from stations at mid-latitudes, we investigate the characteristics of field-aligned currents on the nightside during the April 6, 2000 superstorm. The results indicate that there is an eastward disturbance on the nightside of Northern Hemisphere during the main phase of magnetic storm, while the interplanetary magnetic field （IMF） is continued southward. The positive disturbances in the postmidnight are larger than that in the premidnight. This suggests that upward field-aligned currents develop on the nightside, when the IMF is directed southward. The peak of upward field- aligned currents is located in postmidnight, and it will be more obvious at substorm expansion. We get the conclusion that both partial ring current and region-2 field-aligned current shift to dusk sector. The upward region-2 current is decreased at substorm onset, and intensified after it. We also investigate the relationship between the upward field-aligned currents on the nightside and the auroral electrojets at high latitudes. It shows a good correspondence between region-2 current and the westward electrojet in the postmidnight. We suppose that they are both associated with the convection electric field.

关 键 词：场向电流 国际货币基金组织 中纬度地区 高纬度地区 星际磁场 电流转移 对应关系 对流电场 

分 类 号：P318.22[天文地球—固体地球物理学]