地磁活动与太阳活动对环电流离子成分与位置的影响

EFFECT OF GEOMAGNETIC ACTIVITY AND SOLAR-CYCLE VARIATION ON THE RING CURRENT IONS

根据CRRES卫星上MICS离子成分探测器的观测资料以及前人有关AMPTE卫星的观测数据 ,研究了地磁活动和太阳活动性对环电流成分以及各种环电流离子的最大通量位置的影响 .观测表明相对于地磁平静时期 ,在地磁活动的活跃时期 ,环电流中O+ 、He+ + 和He+ 离子的数密度和能量密度占环电流总数密度和总能量密度的份额增加 ,相反H+ 离子所占的比例却明显减少 .太阳活动极大年时环电流中H+ 离子丰度比极小年时低 ,而O+ 和He+ + 离子的丰度却比太阳活动极小年时高 .卫星数据观测还表明 ,在地球磁暴期间 ,环电流中O+ 离子和He+ 离子的最大通量位置会随着地磁的活动径向移动 ,平均来看太阳活动极大年的能量粒子最大数密度位置距离地球比极小年时约小 0 .5RE(RE为地球半径 ) .

We study the effect of the solar-cycle and geomagnetic activity on the composition and their maximum positions of the ring current ions by using the energetic particle data obtained by MICS instrument on board CRRES satellite and other research results of AMPTE. Observations show that the number density ratio and energy density ratio of O +,He ++ and He + ions to the total ring current all have an increase during geomagnetic active times, whereas that of H + ions exhibits an obvious decrease. Compared with AMPTE observations in the solar minimum, the abundance of the ring current H + is apparently lower in the solar maximum than that during solar minimum. In contrast, the abundance of both O + and He ++ ions are higher. CRRES data also indicate that, in addition to the inward motion of the position of the maximum flux of O + and He + during a geomagnetic storm, the altitude of the maximum number density of the energetic ions is about 0.5 R E lower in the solar maximum than that in the solar minimum.