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利用CRRES/MICS的观测数据 ,研究了磁暴期间内磁层离子成分的变化 .对1 991年两个典型磁暴和 1 2个大磁暴的分析表明 ,组成暴时环电流的离子可以分成两组 ,一组由O+、低能H+和He+组成 ,起源于电离层 (IOP) ;另一组为高能H+和He++,主要来自太阳风 (SOP) .宁静时环电流主要成分为SOP ,大磁暴主相极大时环电流的主要成分是IOP .大磁暴期间离子可被注入到很低的高度 (L =3— 4) .IOP对环电流的贡献随磁暴强度增大而增加 ,在大磁暴主相极大时可达 80 % (数密度 ) .IOP中O+的快速增减是导致Dst指数在磁暴主相期间快速下降和恢复相中快速增长的主要原因 .小磁暴中 (Dst>- 50nT)O+对环电流的贡献可以忽略不计
Using the CRRES / MICS observation data, the changes of ionospheric ion composition during magnetic storms were studied. The analysis of two typical magnetic storms and 12 large storms in 1991 showed that the ions that make up the storm ring current can be divided into two groups, One is composed of O +, low energy H + and He +, and originated from the ionosphere (IOP). The other group is high energy H + and He ++, mainly from the solar wind (SOP). The main component of the ring current at quiet time is SOP, The main component of the current in the ring current is IOP. The ions can be implanted to a very low height (L = 3-4) during the large storms. The contribution of IOP to the ring current increases with increasing storms, (Dst> - 50nT) O + is the main reason for the rapid decrease and recovery of Dst index during the main phase of the storms. The contribution of current is negligible