Nonbouncing Pc 1 wave bursts
Nonbouncing Pc 1 wave bursts
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非弹跳 Pc 1 波爆发
DOI：
10.1029/97ja01080
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发表时间：
1997
影响因子：
--
通讯作者：
P. Lindqvist
中科院分区：
文献类型：
--
作者：
K. Mursula;R. Rasinkangas;T. Bösinger;R. Erlandson;P. Lindqvist
1986年4月11日，在0600 UT左右，一个长Pc 1波事件的磁流体合唱类型开始在地面上，由芬兰脉动磁强计网络记录。在约0.3 Hz的主脉动带观察了几个小时。启动后不久，这一波段平稳地扩展到更高的频率，形成另一个单独的波段，最终达到0.5 Hz。活动期间，“维京海盗”号卫星正在斯堪的纳维亚上空南行，靠近地面网络的MLT扇区。从协调世界时06：50到06：57，维京海盗号观测到一连串频率逐渐增加的Pc 1爆发.最强的爆发可以分为两个单独的波区，其性质略有不同。高纬度地区的频率为0.3 Hz，与地面上的主要Pc 1波段完全一致。低纬度地区包含在地面上观测到的最高频率，约为0.5赫兹。两个波区的纬度范围约为0.5°。他们有轻微不同的归一化频率，阿尔芬速度，和重复周期。最有趣的是，两个波源的重复周期都太短了，爆发是由于两个半球之间的波包反弹。这些结果提供了关于高纬度Pc 1波的新信息，表明它们可以由单独的重复但非反弹的爆发组成。我们认为，长期持有的弹跳波包假设一般是不正确的，并讨论两种替代模型的爆发结构形成在赤道源区域的波。
On April 11, 1986, at about 0600 UT a long Pc 1 wave event of the hydromagnetic chorus type started on the ground, as registered by the Finnish pulsation magnetometer network. The main pulsation band at about 0.3 Hz was observed for several hours. Soon after start, this band smoothly extended to higher frequencies, forming another separate wave band which finally reached up to 0.5 Hz. During the event the Viking satellite was on its southbound pass over Scandinavia, close to the MLT sector of the ground network. From 0650 until 0657 UT, Viking observed a chain of Pc 1 bursts with increasing frequency. The strongest bursts could be grouped into two separate wave regions whose properties differed slightly. The higher-latitude region had a frequency of 0.3 Hz, well in agreement with the main Pc 1 band on the ground. The lower-latitude region contained the highest frequencies observed on the ground at about 0.5 Hz. The latitudinal extent of both wave regions was about 0.5°. They had slightly different normalized frequencies, Alfven velocities, and repetition periods. Most interestingly, the repetition periods of both wave sources were too short for the bursts to be due to a wave packet bouncing between the two hemispheres. The results give new information about the high-latitude Pc 1 waves, showing that they can consist of separate repetitive but nonbouncing bursts. We suggest that the long-held bouncing wave packet hypothesis is generally incorrect and discuss two alternative models where the burst structure is formed at the equatorial source region of the waves.