Correlation study of plasmasheet ions with solar wind and geomagnetic conditions

本文根据搭载于Cluster卫星的CIS/CODIF和RAPID仪器的观测数据,统计研究了等离子体片中的H~+、O~+离子在磁暴期间的时间变化特性,及其对太阳风条件的响应.观测结果表明:(1)磁暴开始前,O~+离子(0～40 keV)数密度保持在较低水平.随着磁暴的发展,O~+数密度缓慢上升,其峰值出现在Dst极小值附近;H~+离子(0～40 keV)数密度在磁暴开始之前的较短时间迅速增加并达到峰值,在磁暴开始之后迅速降低,并在整个主相和恢复相期间保持在相对较低水平.更高能量的离子则在磁暴开始后迅速增多,并在低能O~+离子达到峰值之前达到峰值.因此我们推测磁暴初期从等离子体片注入环电流的主要是...Observations obtained from CIS/CODIF and RAPID instrument onboard Cluster are used to investigate the temporal behavior of H(+) and O(+) ions in the storm time plasmasheet and the relationship between plasmasheet ions and solar wind conditions. It is found that: O(+) The number density of O(+) ions (0 similar to 40 keV) is quite low before SSC, and increases slowly as Dst decreases, reaching its peak value at the vicinity of Dst minimum. The density of W ions enhances greatly shortly before SSC, and decreases sharply after SSC. It keeps at a relatively low level during the whole main phase and recovery phase. Fluxes of energetic H(+) and O(+) ions enhance greatly after SSC and reach their maximum values before their low energy counterparts. It implies that ions injected into ring current at early storm time are mainly H(+) ions and only at later times O(+) ions could significantly affect the ring current. (2) During geomagnetic active times, solar wind pressure, density and electric field are positively correlated with simultaneous H(+) and O(+) number density in the plasma sheet. The dependence of H(+) number density on solar wind parameters is stronger under northward IMF (Interplanetary Magnetic Field), while O(+) number density favors southward IMF. During geomagnetic quiet times, there is no clear evidence for a correlation between solar wind conditions and ions in the plasmasheet.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000273364200001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701SCI(E)中文核心期刊要目总览(PKU)中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)1122931-29425