| 地磁平静期间磁层高能粒子非垂直地磁截止刚度研究 |
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| 引用本文： | 楚伟,秦刚,黄建平,许嵩,泽仁志玛,申旭辉.地磁平静期间磁层高能粒子非垂直地磁截止刚度研究[J].地球物理学报,2021,64(2):410-418. |
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| 作者姓名： | 楚伟 秦刚 黄建平 许嵩 泽仁志玛 申旭辉 |
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| 作者单位： | 应急管理部国家自然灾害防治研究院,北京100085;哈尔滨工业大学(深圳),深圳518055 |
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| 基金项目： | 国家重点研发专项-地球物理探测卫星数据分析处理技术与地震预测应用研究;地震活动期间ZH-1电离层掩星数据异常研究 |
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| 摘 要： | 地磁截止刚度是定量衡量地球磁场对高能粒子屏蔽效应的参数,描述了高能粒子穿越磁层到达指定观测点的带电粒子刚度阈值.人们一直研究垂直方向上的截止刚度,但对作为方向函数的截止刚度,缺少详细研究.我们使用单粒子方法,倒向追踪粒子的运动状态,计算了近地空间不同投掷角度的高能粒子地磁截止刚度,研究发现:(1)天顶方向或者垂直方向的截止刚度通常不是最小地磁截止刚度;(2)最小地磁截止刚度对应的投掷角方向最大为沿着磁场方向,即0°方向;其次为天顶方向,也就是通常所说的垂直方向;然后为180°方向,即磁场的反方向;(3)全球范围截止刚度对应的投掷角分布符合两端上翘的正态分布形态,不考虑两端最大占比,其中心在90°附近;(4)通过地磁平静期间的数值模拟发现,使用垂直方向的截止刚度对比最小截止刚度将平均高估13.17%,最大可能高估70%;(5)不同经纬度高能粒子的截止刚度与投掷角不存在明显关系.我们的研究将对行星际高能粒子以及银河宇宙线进入磁层,尤其是高纬度地区磁层和行星际空间的高能粒子耦合机制具有重要意义.同时对极盖区辐射吸收、高能银河宇宙线造成的大气层化学过程以及极地空间背景等离子体的相关研究具有重要意义.
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| 关 键 词： | 高能粒子 地磁截止刚度 非垂直方向 数值模拟 |
A study on non-vertical geomagnetic cutoff rigidity of magnetosphere energetic particles during geomagnetic quiet period |
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| CHU Wei,QIN Gang,HUANG JianPing,XU Song,ZEREN ZhiMa,SHEN XuHui.A study on non-vertical geomagnetic cutoff rigidity of magnetosphere energetic particles during geomagnetic quiet period[J].Chinese Journal of Geophysics,2021,64(2):410-418. |
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| Authors: | CHU Wei QIN Gang HUANG JianPing XU Song ZEREN ZhiMa SHEN XuHui |
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| Institution: | (National Institute of Natural Hazards,Ministry of Emergency Management of China,Beijing 100085,China;Harbin Institute of Technology,Shenzhen,Shenzhen 518055,China) |
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| Abstract: | Geomagnetic cutoff rigidity is a parameter that quantitatively measures the shielding effect of the earth′s magnetic field on energetic particles.People have been studying the cutoff rigidity in the vertical direction,but the cutoff rigidity as a function of direction received less detailed studies.We used the single particle method to track the motion of the particles backwards,and calculated the geomagnetic cutoff rigidity of energetic particles at different pitch angles in near-Earth space.The study found that:(1)The cutoff rigidity in the vertical direction is usually not the minimum geomagnetic cutoff rigidity.(2)The maximum pitch angle direction corresponding to the minimum geomagnetic cutoff rigidity is along the magnetic field direction,followed by the vertical direction,and then the 180-degree direction,which is opposite to the magnetic field direction.(3)The pitch angle distribution corresponding to the global cutoff rigidity conforms to the normal distribution pattern of upturning at both ends,regardless of the maximum proportion of the two ends,and the center appears around 90 degrees.(4)Through numerical simulation during geomagnetic quiet period,it is found that using the vertical cutoff rigidity in comparison with the minimum cutoff rigidity will overestimate by an average of 13.17%and the maximum possible overestimation is 70%.(5)There is no obvious relationship between the cutoff rigidity of energetic particles at different latitude and longitude and the pitch angle.Our study will be of great significance to the access of interplanetary energetic particles and the cosmic rays into the magnetosphere,especially the coupling mechanism of energetic particles between the magnetosphere and interplanetary space.At the same time,it is of great significance to the radiation absorption in the polar cap area,the chemical process of the atmosphere caused by the energetic galactic cosmic rays and the related research of the polar space background plasma. |
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| Keywords: | Energetic Particles Geomagnetic Cutoff Rigidity Non-vertical Direction Numerical Simulation |
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