基于范阿伦卫星观测数据的等离子体层嘶声全球分布的统计分析

发布时间：2019-01-13 07:28

【摘要】：等离子体层嘶声是引起辐射带电子投掷角散射进而沉降到地球大气层的重要物理机理,也被认为是导致地球内、外辐射带之间槽区形成的主因,因此研究空间等离子体层嘶声的全球分布特性具有重要科学意义.本文利用范阿伦探测双星中的A星从2012年9月到2015年5月长达33个月的高质量波动观测数据,详细计算了等离子体层嘶声的平均波幅和发生率,建立了等离子体层嘶声的全球分布数据库,并细致分析了其场强幅度随地磁活动水平、磁壳值L、地磁纬度、磁地方时的统计变化规律.结果表明,等离子体层嘶声的平均波幅与地磁活动剧烈程度具有很强的相关性,并表现出明显的昼夜不对称性.随着地磁活动的增强,日侧等离子体层嘶声的平均波幅相应增大,增强的区域集中在2.5L4,但是夜侧等离子体层嘶声的平均波幅反而下降.另外,不同幅度的等离子体层嘶声随地磁活动的变化表现出不同的响应特性.随着地磁活动水平的增强,较小幅度(5—30 pT)的等离子体层嘶声的日侧发生率减小,夜侧发生率增大;更强幅度(30 pT)的等离子体层嘶声的变化特性正好相反,日侧发生率增大,夜侧发生率减小.在各种地磁活动条件下,磁赤道面附近及中纬地区等离子体层嘶声都广泛存在,波动幅度位于5—30 pT范围的嘶声发生概率最大.以上统计观测结果为现有的等离子体层嘶声全球分布模型提供了合理、可靠的补充,充分说明不同场强幅度的等离子体层嘶声在2L6的内磁层空间经常性地存在,为定量分析、模拟不同能量、不同投掷角的地球辐射带电子在不同太阳风与磁层背景条件下的动态时空变化过程提供了重要参数支持.
[Abstract]:The hoarseness of the plasma layer is an important physical mechanism that causes the scattering of electrons from the radiation band into the earth's atmosphere, and is also considered to be the main cause of the formation of the trough region between the outer and outer radiation bands in the earth. Therefore, it is of great scientific significance to study the global distribution of hoarseness in space plasma layer. In this paper, the mean amplitude and incidence of hoarseness in plasma layer are calculated in detail by using the observation data of high quality wave from September 2012 to May 2015, which are 33 months from September 2012 to May 2015. The global distribution database of hoarseness sound in plasma layer is established, and the statistical variation of field intensity with geomagnetic activity level, magnetic shell value L, geomagnetic latitude and local magnetic time is analyzed in detail. The results show that the average amplitude of hoarseness in the plasma layer is strongly correlated with the intensity of geomagnetic activity and shows obvious diurnal asymmetry. With the increase of geomagnetic activity, the average amplitude of the hoarseness of the plasma layer on the day side increases accordingly, and the enhancement region is concentrated at 2.5L4, but the average amplitude of the hoarseness sound in the plasma layer decreases at night. In addition, the plasma layer hoarseness with different amplitude shows different response characteristics with geomagnetic activity. With the increase of geomagnetic activity, the incidence of sizzling in plasma layer decreased in a small amplitude (5-30 pT), and the incidence of nocturnal side increased. The variation of plasma layer hoarseness with a stronger amplitude (30 pT) is just the opposite. The incidence of the day side increases and the night side rate decreases. Under various geomagnetic conditions, hoarseness in plasma layer is widespread in the vicinity of the magnetic equator and in the middle latitude region, and the probability of hoarseness occurring in the range of 5-30 pT is the highest. The above statistical observations provide a reasonable and reliable supplement to the existing global distribution model of hoarseness sound in plasma layer. It fully shows that the hoarseness sound of plasma layer with different field intensities frequently exists in the inner magnetosphere of 2L6, which is a quantitative analysis. The simulation of the dynamic spatiotemporal variation of electrons in different solar wind and magnetosphere with different energy and different throwing angles provides important parameters for the simulation.
【作者单位】：武汉大学电子信息学院空间物理系;
【基金】：国家自然科学基金(批准号:41204120,41304130,41474141,41574160) 中国博士后科学基金(批准号:2013M542041,2014T70732,2015M582265) 国家级大学生创新创业项目(批准号:201510486081)资助的课题~~
【分类号】：O422.8

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