• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Geophysical Research, A. Space Physics: JGR >A statistical study of proton precipitation onto the Martian upper atmosphere: Mars Express observations
【24h】

A statistical study of proton precipitation onto the Martian upper atmosphere: Mars Express observations

机译：火星高空观测上质子在火星高层大气上的降水的统计研究

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

Due to the small size of the Martian magnetic pile-up region, especially at the subsolar point, heated protons with high enough energy can penetrate the induced magnetosphere boundary without being backscattered, i.e., they precipitate. We present a statistical study of the downgoing ～ keV proton fluxes measured in the Martian ionosphere by the Analyzer of Space Plasma and Energetic Atoms experiment onboard the Mars Express spacecraft. We find that on the dayside, the events of proton penetration occur during 3% of the observation time; the precipitation is an intermittent phenomenon. The proton events carry on average ～0.2% of the incident solar wind flux. Therefore, the induced magnetosphere is an effective shield against the magnetosheath protons. The events are more frequent during fast solar wind conditions than during slow solar wind conditions. The sporadic proton penetration is thought to be caused by transient increases in the magnetosheath temperature. The precipitating flux is higher on the dayside than on the nightside, and its spatial deposition is controlled by the solar wind convective electric field. The largest crustal magnetic anomalies tend to decrease the proton precipitation in the southern hemisphere. The particle and energy fluxes vary in the range 10 ~4-10~6 cm~(-2) s~(-1) and 10 ~7-10~9 eVcm~(-2) s~(-1), respectively. The corresponding heating for the dayside atmosphere is on average negligible compared to the solar extreme ultraviolet heating, although the intermittent penetration may cause local ionization. The net precipitating proton particle flux input to the dayside ionosphere is estimated as 1.2 · 10 ~(21) s~(-1). Key Points Statistics of precipitating protons in the Martian ionosphere with Mars ExpressH+ fluxes are controlled by the solar wind convective electric fieldStrong crustal fields decrease the H+ precipitation in the subsolar region
机译：由于火星磁性堆积区域的尺寸小，特别是在太阳下点，具有足够高能量的加热质子可以穿透感应磁层边界而不会反向散射，即它们会沉淀。我们对火星快船上的空间等离子和高能原子分析仪在火星电离层中测得的下行keV质子通量进行了统计研究。我们发现，在白天，质子渗透的事件发生在观测时间的3％内。降水是一种间歇现象。质子事件平均约占入射太阳风通量的0.2％。因此，感应磁层是对磁石质子的有效屏蔽。在快速太阳风条件下的事件比在慢速太阳风条件下的事件更为频繁。零星的质子渗透被认为是由磁化石温度的瞬时升高引起的。白天的降水通量比夜晚的高，并且其空间沉积受太阳风对流电场控制。最大的地磁异常倾向于减少南半球的质子沉淀。粒子通量和能量通量分别在10〜4-10〜6 cm〜（-2）s〜（-1）和10〜7-10〜9 eVcm〜（-2）s〜（-1）范围内变化。尽管间歇性渗透可能导致局部电离，但与日光极端紫外线加热相比，白天大气的相应加热平均可以忽略不计。输入到日间电离层的净沉淀质子粒子通量估计为1.2·10〜（21）s〜（-1）。火星ExpressH +通量由火星Expressh +通量控制在火星电离层中沉积质子的统计数据强地壳场降低了近太阳能区的H +沉淀

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