...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Geophysical Research. Biogeosciences >Widely spaced wave-particle observations during GEOTAIL and Wind magnetic conjunctions in the Earth's ion foreshock with near-radial interplanetary magnetic field
【24h】

Widely spaced wave-particle observations during GEOTAIL and Wind magnetic conjunctions in the Earth's ion foreshock with near-radial interplanetary magnetic field

机译：地球离子前震中近地行星际磁场在地球动力学和风磁交会期间的宽间隔波粒观测

获取原文
获取原文并翻译 | 示例
   

获取外文期刊封面封底 >>

       
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Several events have been identified of an ion foreshock extending up to 250 RE upstream of the Earth. These events occur mostly during periods of slowly drifting radial interplanetary magnetic field (IMF) when the 1-min average values of the strengths of the IMF and the solar wind (SW) speeds are mostly steady. For their analysis an analytical solution to the problem of the closest approach of an IMF line to two spacecraft is given. We used this method to find intervals of magnetic conjunction between the bow shock and the upstream regions at GEOTAIL and Wind. This solution is obtained by determining the minimum angle #theta# (as a function of time) between the mean direction of the IMF (measured at Wind) and the vectordifference (rWI-r) of the locations of Wind and the point (attached on the field line) which went earlier by GEOTAIL. Here we take into account the mean drift of the flux lines with the SW, by assuming that the spacecraft were located in the same heliospheric magnetic domain. We have tested this method against a set of selected cases which show a steady presence of the ion foreshock close to the bow shock (GEOTAIL) and its sporadic presence far upstream (Wind). We have found our method to be accurate within a few Earth radii (RE). We have identified an outstanding candidate for the bow shock, GEOTAIL, and Wind sequential magnetic conjunction, which occurred on June 11, 1995. Additionally, this diagnostic technique has been applied to nine more intervals of simultaneous occurrences of intensity enhancements of broadband ultralow-frequency (ULF) waves, and fluctuating fluxes of scattered energetic ions (40-140 keV). Very broad ion foreshock regions (> 40 RE) are commonly observed during the subset of events characterized by a high-speed SW. The observed frequencies of the ULF waves are basically enhanced transversal modes in the range from approx 1/10 to 2/3 of proton cyclotron frequency, f Flucturations in the energetic ion fluxes were also observed in this frequency range for all the cases. Therefore we argue that the nature of the coupling between ULF waves and energetic ions is similar both in the near as well as far upstream regions of the Earth's bow shock.
机译：已经确定了离子前震延伸到地球上游250 RE的几个事件。这些事件主要发生在径向星际磁场（IMF）缓慢漂移的时期，当时IMF的强度和太阳风（SW）速度的1分钟平均值基本稳定。为了进行分析，给出了对IMF线最接近两个航天器的问题的解析解决方案。我们使用这种方法来找到弓激波与GEOTAIL和Wind上游区域之间的磁结合间隔。通过确定IMF的平均方向（在风中测量）与风和该点（附加在）上的矢量差（rWI-r）之间的最小角度＃theta＃（作为时间的函数）来获得此解决方案。场线），这是GEOTAIL早先提出的。在这里，我们通过假设航天器位于相同的日球磁场域中来考虑SW的通量线的平均漂移。我们已经针对一组选定的案例测试了该方法，这些案例显示出在弓形冲击附近（GEOTAIL）稳定存在离子前震，在上游（Wind）具有零星存在。我们发现我们的方法在几个地球半径（RE）内是准确的。我们已经确定了1995年6月11日发生的弓形激波，GEOTAIL和Wind顺序磁合的杰出候选者。此外，该诊断技术已应用于宽带超低频同时增强的另外9个间隔（ULF）波，以及高能散射离子的波动通量（40-140 keV）。在以高速SW为特征的事件子集中，通常观察到非常宽的离子前震区域（> 40 RE）。观察到的ULF波的频率基本上是质子回旋加速器频率的大约1/10至2/3范围内的增强横向模式。在所有情况下，在该频率范围内还观察到了高能离子通量的波动。因此，我们认为，在地球弓激波的近端和上游区域，ULF波与高能离子之间的耦合性质相似。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号