Joint Study on the M-I Coupling in the Southern Polar Cap

摘要利用1993 ~ 1997年南极高纬度自动地球物理观测站（AGOs）获得的极光图像、地磁场、CAN波和VLF波等资料，与Super DARN高频雷达网和卫星资料进行对比分析，探讨极帽区极光和地磁活动的机制。主要发现如下：1)pc1爆发发生在极帽区和极尖、极裂区，伴随着地磁重联引起的脉冲地磁变化。2)在地磁纬度70度附近，pc3波在白天频繁出现，而在80度附近，pc3的地方时依赖性较小。通过与行星际磁场（IMF）的比较，推断pc3源位于激波锋面上游，对于小锥角情况，pc3从太阳下区进入磁层，对于大锥角情况，pc3从高纬度或低纬度边界层（LLBL）进入磁层。3) pc5在地磁纬度72 ~ 74度范围内的动力谱有时表现为奇共振波引起的拱状结构。在北向IMF条件下，pc5的出现频率变大，暗示了pc5的产生与地磁重联有关。4)磁脉冲事件（MIE）发生在IMF向北时观测到的4格型对流反转边界。MIE以2公里/秒的速度向西沿经度60度移动。

Data obtained by Automatic Geophysical Observatories (AGOs) located at Antarctic high latitude areas in the period of 1993 - 1997, such as aurora image, geomagnetic field, CAN, and VLF waves, have been analyzed carefully in order to investigate the mechanisms of aurora and geomagnetic activities in polar cap region, comparing with Super DARN HF radar network and satellite data. The most important findings are as follows : 1) Pc 1 bursts occur in polar cap region as well as cusp and cleft region, accompanying an impulsive geomagnetic variation caused by geomagnetic reconnection. 2) Pc 3 waves are frequently observed during daytime near 70 degree in geomagnetic latitude, while around 80 degree local time dependency of Pc 3 is comparably small. Based on the comparison with interplanetary magnetic field (IMF) it is inferred that Pc 3 source is located at upstream of shock front and the Pc 3 penetrates into the magnetosphere from subsolar region for small cone angle case while from high latitude in the tail region or low latitude boundary layer (LLBL) for large cone angle case. 3) Dynamic spectrum of Pc 5 in geomagnetic latitude range of 72 - 74 degree sometimes shows an arch structure caused by odd resonance wave. The occurrence frequency of Pc 5 becomes large in northward IMF condition, which implies relationship between generation of Pc 5 and geomagnetic reconnections. 4) Magnetic impulse event (MIE) occurs in the convection reversal boundary of 4 cell pattern observed in the case of northward IMF. MIE travels westward by 60 degree in longitude at a speed of 2 km/sec.