...
  • 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 >Particle simulation of the auroral zone showing parallel electric fields, waves, and plasma acceleration
【24h】

Particle simulation of the auroral zone showing parallel electric fields, waves, and plasma acceleration

机译：极光区域的粒子模拟显示平行电场，波和等离子体加速度

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

This paper examines the self-consistent generation of the large-scale quasi-static, parallel electric fields that are formed in the auroral zone and how these fields affect local plasma distributions. A one-dimensional electrostatic particle-in-cell simulation is employed in this study with its axis aligned along a dipolar magnetic field line that includes the magnetic mirror force as well as a cold dense ionosphere at low altitudes. Earthward drifting plasma from the magnetotail is injected into the system at the high-altitude end of the simulation. Simulation results show that injection of magnetotail plasma leads to the mirroring of ions at lower altitudes than electrons, thereby creating a large-scale, quasi-static, parallel potential drop. In addition, the results show that the magnitude of the large-scale potential drop depends on the earthward directed drift speed; the drop can be as large as 2 kV over a distance of a few thousand kilometers for inflowing ion beam energies of 10 to 25 keV. The potential gradient corresponds to a parallel electric field that is directed away from the Earth. The field accelerates ionospheric ions away from the Earth, and the accelerated ions form the Earth. The field accelerates ionospheric ions away from upwelling beams with drift speeds that are in approximate agreement with observed high-altitude auroral ion beams. Electrons are accelerated earthward and appear as a precipitating high-energy tail in low-altitude ionospheric distribution functions. A broadband plasma wave spectrum is generated where the magnetotail and ionospheric plasma interact, and it plays an important role in auroral dynamics by modifying local plasma distributions. Not only do these modifications of the local distributions affect plasma flow in the region, they also decrease the magnitude of the large-scale potential drop by drawing off energy from the inflowing distributions that otherwise would support the potential drop.
机译：本文研究了在极光区形成的大规模准静态，平行电场的自洽产生，以及这些电场如何影响局部血浆分布。本研究采用一维静电粒子模拟，其轴沿偶极磁场线对齐，该极线包括磁镜力以及低海拔的冷致密电离层。来自磁尾的向地球漂移的等离子体在模拟的高空端注入到系统中。仿真结果表明，磁尾等离子体的注入会导致离子在比电子低的高度处发生镜像，从而产生大规模的准静态平行电势降。此外，结果表明，大范围电势下降的幅度取决于向地球的漂移速度。对于流入的10至25 keV的离子束能量，在数千公里的距离内压降可能高达2 kV。电位梯度对应于指向远离地球的平行电场。该场加速电离层离子离开地球，加速的离子形成地球。该场以与观测到的高空极光离子束大致一致的漂移速度使电离层离子加速离开上升流束。电子向地球加速，并在低空电离层分布函数中以沉淀的高能尾巴的形式出现。在磁尾和电离层等离子相互作用的地方会产生宽带等离子频谱，它通过修改局部等离子分布在极光动力学中发挥重要作用。这些局部分布的修改不仅会影响该区域中的等离子体流动，而且还会通过从流入的分布中抽取能量来降低大规模电势下降的幅度，否则会支持电势下降。

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