HR: 1340h
AN: SM13A-1182    [Abstracts]
TI: Geomagnetic Activity Dependence of the Ratio N+/O+ in the Ring Current
AU: * Fu, S
EM: suiyanfu@pku.edu.cn
AF: Institue of Space Physics and Technology, School of Earth and Space Sciences/ Peking University, Beijing, 100871 China
AU: Liu, W
EM: liuwenlong@pku.edu.cn
AF: Institue of Space Physics and Technology, School of Earth and Space Sciences/ Peking University, Beijing, 100871 China
AU: Zong, Q
EM: zong@bu.edu
AF: Center for Space Physics, Center for Space Physics, Boston University 725 Commonwealth Avenue , Boston, Mas 02215 United States
AU: Pu, Z
EM: zypu@pku.edu.cn
AF: Institue of Space Physics and Technology, School of Earth and Space Sciences/ Peking University, Beijing, 100871 China
AU: Ruan, P
EM: ruanpeng@pku.edu.cn
AF: Institue of Space Physics and Technology, School of Earth and Space Sciences/ Peking University, Beijing, 100871 China
AB: Based on the energetic particle measurement obtained by CRRES/MICS, ion composition variations in the ring current have been investigated. Observation shows that in addition to O+ and H+, N+ ions are also an important composition in the ring current region. The ratio of N+/O+ during geomagnetic quiet times is about 0.26, while a smaller valued could be found for strong active times. The variation of the ratio follows the same trace as the Dst index. Through a statistic study, it is demonstrated that the ratio of N+/O+ decreases with an enhanced geomagnetic activity for strong storms, whereas for small storms, there is no obvious correlations of the ratio to the activity level. Based on the IRI model, we show that different ion species reach their peak values at different altitude. The maximum of oxygen ions sit in a lower altitude than that of nitrogen ions. It is thus implied that the altitude of the ion up-flowing in the ionosphere is closely related to the geomagnetic activity. The stronger storms, the lower ionosphere could be involved in the magnetosphere-ionosphere coupling.
DE: 2720 Energetic particles, trapped
DE: 2730 Magnetosphere--inner
DE: 2778 Ring current
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting