αα指数与IMF的关系

THE IMF AND ITS ASSOCIATED GEOMAGNETIC αα INDEX AND STORM

本文用磁暴期间最大αα指数考察了行星际磁场强度Ｂ及其扇形边界对地磁场的影响，根据。与Ｂ的线性关系提出了按Ｂ对磁暴进行分类，并统计了每类磁暴特性与相应的太阳风参数的特性，发现行星际磁场的两类扇形边界扫过地球后有不同的地磁效应．

The influences of the interplanetary magnetic field (IMF) total intensity B andits sector boundary on the magnetic field of the Earth are investigated by examination of the maximum αα indices during geomagnetic storms. The stroms are classifiedinto three types according to their different linear'correlations between the IMF andthe αα indices. Each type of the storms has its characteristics in association with theappropriate solar wind parameters. There are two geomagnetic effects in response tothe two spiral IMF sector boundaries passing the Earth. It seems that the αα indexmay take the precedence over others in the study of solar--terrestrial couplings.