...
  • 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 >Numerical estimates of drift loss and Dst effect for outer radiation belt relativistic electrons with arbitrary pitch angle
【24h】

Numerical estimates of drift loss and Dst effect for outer radiation belt relativistic electrons with arbitrary pitch angle

机译：数值漂移的估计损失和Dst的效果为外辐射带相对论性电子具有任意螺距角

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

Satellite observations often show that relativistic electron fluxes that decrease during ageomagnetic storm main phase do not recover their prestorm level even when thestorm has substantially recovered. A possible explanation for such sustained flux dropoutis that the electrons that move to larger shells (L shells) aided by the disturbance stormtime (Dst) effect associated with the main phase geomagnetic field depression may besuffering drift loss to the magnetopause, resulting in irreversible (nonadiabatic) fluxdecreases during a geomagnetic storm. In this study, we have numerically evaluated thedrift loss effect by combining it with the Dst effect and including off-equatoriallymirroring electrons for three different storm conditions obtained by averaging 95geomagnetic storms that occurred from 1997 to 2002. Using the Tsyganenko T02 modeland our own simplified method, we estimated the storm time flux changes based on theguiding center orbit dynamics. Assuming that there is no competing source mechanismtaking place at the same time, our calculations of the electron fluxes at equatorial midnightsuggest that the drift loss when combined with the Dst effect can be responsible forflux dropouts, which can be seen even inside the geosynchronous orbit during stormperiods. Specifically, by evaluating omnidirectional flux values at three specific times thatcorrespond to the storm onset time, the time of minimum Dst value, and the end of theDst recovery, we have obtained the following numerical results. First, for the strong stormwith –150 nT < Dst_(min)≤ –100 nT, the combined drift loss and Dst effect can cause acomplete dropout of the electron flux for r ≤ ~5 RE at the end of the storm recovery. A nearlyfull recovery of the particle flux by the adiabatic Dst effect is seen only for r < ~5 R_E.For themoderate storm with –100 nT < Dst_(min)≤ –50 nT, the overall flux decrease level at theend of the storm recovery is less significant compared to that of the strong storm. However,the combined loss effect can still penetrate into r 5 RE, leading to some partial dropout ofthe flux. For the severe storm with Dst_(min) ≤ –150 nT, the flux dropout is far moresignificant than for the other two storms, indicating that the combined drift loss and Dsteffect can even reduce the flux level at an inner region of r ~ 4 R_E.But in this case, the solarwind dynamic pressure is so high that the dayside magnetopause can cross thegeosynchronous orbit. Consequently, the flux dropouts seen in actual observations can beprimarily attributed to a fast and direct loss to the magnetopause at times when themagnetopause crosses the geosynchronous orbit. It is possible that our numerical resultsmay quantitatively change to some extent with different magnetospheric models andassumptions and may also change depending on the validity of the fully adiabatic invariantsassumption.
机译：卫星观测显示相对论性电子通量减少期间ageomagnetic风暴主要阶段不恢复即使thestorm prestorm水平明显恢复。这样持续dropoutis通量电子转移到更大的炮弹壳(左)由于干扰stormtime (Dst)的效果与地磁场的主要阶段抑郁症可能besuffering漂移损失磁层,导致不可逆的(非绝热的)在地磁fluxdecreases风暴。评估thedrift损失效应相结合Dst的效应,包括off-equatoriallymirroring电子三不同的风暴条件获得的平均发生在1997年至95年地磁风暴2002. 简化的方法,我们估计暴风雨通量变化基于theguiding中心轨道动力学。源mechanismtaking地点在同一时间,我们的电子通量的计算赤道midnightsuggest漂移损失当结合Dst的效果负责forflux辍学,也可以看到甚至在地球同步轨道在里面stormperiods。全向通量三个特定的值次thatcorrespond暴风雨起始时间,最小的Dst价值,theDst的结束复苏,我们获得以下数值结果。stormwith——150 nT < Dst_ (min)≤100特斯拉,《结合漂移和Dst效应会导致损失已有电子通量的辍学r≤~ 5暴风雨结束时恢复。复苏的粒子通量绝热Dst效果只有r < ~ 5 R_E。与-100元< Dst_ themoderate风暴(min)≤-50nT,整体通量水平的降低暴风雨复苏相比不那么重要强烈的风暴。损失的影响仍然可以渗透r 5再保险,导致部分通量辍学。严重的风暴和Dst_ (min)≤-150元,辍学是moresignificant比通量其他两个风暴,表明组合漂移损失和Dsteffect甚至可以减少流量水平的内部区域r ~ 4 R_E。情况下,solarwind动态压力是如此之高的光面的磁层可以交叉thegeosynchronous轨道。实际的观测可以辍学beprimarily归因于一个快速和直接损失在时候themagnetopause磁层穿过地球同步轨道。我们的数值resultsmay定量在某种程度上有不同的变化磁性层的模型andassumptions也可以改变取决于充分的有效性

著录项

相似文献

  • 外文文献
  • 中文文献
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