EFFECT OF GEOMAGNETIC ACTIVITY AND SOLAR-CYCLE VARIATION ON THE RING CURRENT IONS
地磁活动与太阳活动对环电流离子成分与位置的影响

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.