地磁脉动Pc5在2000年7月15～16日磁暴期间的特征

采用IMAGE链22个台站的地磁脉动10 s数据，分析了2000年6月15～16日磁暴期间Pc5地磁脉动的频率、振幅、位相和极化特征：（1）磁暴初相和主相期间Pc5脉动的主频率随纬度的升高而降低，但是恢复相期间主频率随纬度的升高而升高，主相期间Pc5的主频率比初相和恢复相期间的低；（2）Pc5脉动初相期间的振幅有一个主峰在64°N附近，主相期间在66°N附近，恢复相期间在71°N附近；位相在主峰两侧随着纬度变化了大约180°， 从初相到恢复相主峰位置向高纬地区大约移动了7°；（3）Pc5地磁脉动的偏振极化椭圆初相期间在PEL站（6346°N）接近线偏振，主相期间在MAS站（6607°N）接近线偏振，恢复相期间在BJN站（7133°N）接近线偏振，并分别在这几个台站两侧的偏振椭圆的旋转方向反向.

CHARACTERISTICS OF Pc5 ULF WAVE DURING THE MAGNETIC STORM ON JULY 15～16, 2000

Pc5 ULF waves during the magnetic storm on July 15～16, 2000 have been studied using ground observations at IMAGE chain containing 22 stations. During the initial phase and main phase of the magnetic storm the main frequency of Pc5 increases with the decreasing latitude, while during the recovery phase the variation of the main frequency with latitude is opposite. The main frequency of Pc5 during the main phase is lower than that during the initial and recovery phases. The amplitude peaks of Pc5 during the initial, main and recovery phases occur near 64°N, 66°N and 71°N, respectively. The polarizations ellipse of Pc5 becomes linear polarization at stations PEL(63.46°N), MAS (66.07°N) and BJN (71.33°N) during the initial, main and recovery phases, respectively.