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首页> 外文期刊>Journal of atmospheric and solar-terrestrial physics >High-latitude geomagnetic pulsation response to the passage of the front edge of the interplanetary magnetic cloud of January 10, 1997
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High-latitude geomagnetic pulsation response to the passage of the front edge of the interplanetary magnetic cloud of January 10, 1997

机译：对1997年1月10日行星际磁云前缘通过的高纬度地磁脉动的响应

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摘要

In this paper we studied the high-latitude long period geomagnetic pulsations excited during the first hours (0430-0830 UT) of the magnetic cloud impact on January 10, 1997. In this study we analysed the ground-based data of the IMAGE magnetometers and the Scandinavian network of ～30 MHz riometers. Two time intervals were selected. the first interval (0430-0600 UT) corresponds to the passage of the compression region on the front edge of the magnetic cloud. During this interval bursts of geomagnetic and riometer data pulsations at frequency range of 1-3 mHz as well as a magnetic substorm were observed at polar latitudes (Λ > 72°) with the strongest amplitudes near a footprint of the open/closed field lines boundary. The waves propagated rapidly eastward at ～6-7 km/s and had an azimuthal wave number m ～ 12. This seems to be inconsistent with the main signature of a field line resonance. The green (557.7 nm) optical emissions were observed at that time at Spitzbergen. The emissions moved rapidly eastward at about the same speed. We speculate that high-latitude geomagnetic pulsations under consideration were excited at the ionosphere latitudes, near the polar cusp footprint. The waves could be associated with quasi-periodic variations in the ionospheric conductivity produced by the particle precipitation oscillations. As the alternative hypothesis we could assume the direct penetration of solar wind compression or Alfven waves to the polar cap. The waves can modulate the particle precipitation produced the quasi-periodic variation of ionospheric conductivity. The second time interval (0600-0830 UT) corresponds to an abrupt increasing of the solar wind dynamic pressure, observed about 2 h after the passage of the magnetic cloud. contrary to the first interval, the strongest amplitudes of geomagnetic and cosmic noise absorption pulsations were observed in closed magnetosphere, at Λ ～ 66°, and showed the properties of the typical field line resonance.
机译：在本文中，我们研究了1997年1月10日磁云撞击的最初几个小时（0430-0830 UT）激发的高纬度长期地磁脉动。在本研究中，我们分析了IMAGE磁强计的地面数据和〜30 MHz的斯堪的纳维亚网络。选择了两个时间间隔。第一间隔（0430-0600 UT）对应于压缩区域在磁云前边缘的通过。在此间隔期间，在极地纬度（Λ> 72°）处观察到了1-3 mHz频率范围内的地磁和riometer数据脉动以及磁亚暴，在开/闭磁场线边界的足迹附近具有最强的振幅。这些波以〜6-7 km / s的速度快速向东传播，并具有m〜12的方位角波。这似乎与磁力线共振的主要特征不一致。当时在Spitzbergen观察到绿色（557.7 nm）的光发射。排放物以大约相同的速度迅速向东移动。我们推测正在考虑中的高纬度地磁脉动是在电离层纬度处，在极尖尖端附近被激发的。这些波可能与粒子沉淀振荡产生的电离层电导率的准周期变化有关。作为替代假设，我们可以假设太阳风压缩或Alfven波直接渗透到极地帽。这些波可以调制产生电离层电导率的准周期变化的粒子沉淀。第二时间间隔（0600-0830 UT）对应于太阳风动压的突然增加，在磁云通过后大约2小时观察到。与第一个间隔相反，在封闭的磁层中，在Λ〜66°处观察到了最强的地磁和宇宙噪声吸收脉动振幅，并显示了典型场线共振的特性。

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