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

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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.