Abstract:

A series of solar flare and coronal mass ejection (CME) event occurred in July of 2000, particularly the largest flare (X5.7/3B) with CME on 14 July since 1989, which induced a great geomagnetic storm with Dst index reaching -300nT. A set of data is obtained from the Chinese Antarctic Zhongshan Station (ZHS,INT Lat. 74.5°, L≈14), which is located at cusp latitude, and from the ACE satellite. Analyzed these data and got the results as follows: a lot of solar highly energized particles penetrated into the polar ionosphere and ionized it, which significantly increased the cosmic noise absorption (CNA) and blanked the DPS 4 data for more than two days. The magnetic pulsation in Pc 3/5 frequency band on the ground has a high relation with the fluctuation of interplanetary magnetic field (IMF) Bz, which shows the contribution of interplanetary MHD waves to the Pc 3/5 pulsation on the ground. The Pc 3/5 pulsation was intensified much during the great magnetic storm. H component of the magnetic field at ZHS varied with the IMF Bz but lagged about 8-10h, while Dst index responded to the variation of the IMF Bz very quickly, which suggested that the magnetic storm occurred at low latitude firstly and then effected the ionospheric current at high latitude.