THE GEOMAGNETIC RESPONSE OF JULY 2000 EVENT

The geomagnetic field responds to the July 2000 space event much. A great storm （magnetic index K = 9） occurred from July 15 to July 18. There is a sudden commencement with amplitudes about 200-300 nT in China region. The maximum amplitudes during the main phase in China region are about 500-600 nT. That is infrequent for a few years. The B_z component of IMF is turning to southward when the main phase of the storm begins, and after the southward component （B_z＜ 0) decrease to the minimum, two hours later the storm recovery phase begins. The paper shows that there are some relationship between the solar wind and the storm.