Statistical study of chorus wave distributions in the inner magnetosphere using Ae and solar wind parameters
Statistical study of chorus wave distributions in the inner magnetosphere using Ae and solar wind parameters
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DOI：
10.1002/2014ja019939
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发表时间：
2014-08-01
影响因子：
2.8
通讯作者：
Boynton, Richard
中科院分区：
文献类型：
--
作者：
Aryan, Homayon;Yearby, Keith;Boynton, Richard
地球辐射带内的高能电子对地球静止卫星构成严重危害。电子与合唱波的相互作用在辐射带电子的加速和损失中起着重要作用。常见的方法是呈现由地磁指数表示的不同地磁活动值下内磁层中的波分布模型。然而，研究表明，只有约50%的地磁暴会增加地球静止轨道相对论电子通量，20%会导致相对论电子通量减少，其余30%则相对没有影响。这强调了包含太阳风参数的重要性，例如体积速度 (V)、密度 (n)、流动压力 (P) 和垂直行星际磁场分量 (Bz)，这些参数已知在控制地球静止轨道的高能通量方面主要有效。因此，在本研究中，波分布的参数集被扩展为除了地磁活动之外还包括太阳风参数。本研究结合了OMNI数据库中的地磁指数和太阳风参数，检查了近4年（2004年1月1日至2007年9月29日）双星TC1场波动数据的时空分析，以提出合唱波的波磁场强度作为磁本地时间、L壳（L）、磁纬度（lambda（m））、地磁活动和太阳风参数的函数的综合模型。一般来说，结果表明，合唱发射的强度不仅取决于地磁活动，还取决于速度和南向行星际磁场 Bs (Bz < 0) 的太阳风参数，这显然是最有影响力的太阳风参数。在活跃条件、高太阳风速度、低太阳风密度、高压和高 Bs 条件下，观察到最大峰值合唱强度约为 50 pT。低频段合唱的平均合唱强度比相应的高频段合唱更广泛、更强。
Energetic electrons within the Earth's radiation belts represent a serious hazard to geostationary satellites. The interactions of electrons with chorus waves play an important role in both the acceleration and loss of radiation belt electrons. The common approach is to present model wave distributions in the inner magnetosphere under different values of geomagnetic activity as expressed by the geomagnetic indices. However, it has been shown that only around 50% of geomagnetic storms increase flux of relativistic electrons at geostationary orbit while 20% causes a decrease and the remaining 30% has relatively no effect. This emphasizes the importance of including solar wind parameters such as bulk velocity (V), density (n), flow pressure (P), and the vertical interplanetary magnetic field component (Bz) that are known to be predominately effective in the control of high energy fluxes at the geostationary orbit. Therefore, in the present study the set of parameters of the wave distributions is expanded to include the solar wind parameters in addition to the geomagnetic activity. The present study examines almost 4 years (1 January 2004 to 29 September 2007) of Spatio-Temporal Analysis of Field Fluctuation data from Double Star TC1 combined with geomagnetic indices and solar wind parameters from OMNI database in order to present a comprehensive model of wave magnetic field intensities for the chorus waves as a function of magnetic local time, L shell (L), magnetic latitude (lambda(m)), geomagnetic activity, and solar wind parameters. Generally, the results indicate that the intensity of chorus emission is not only dependent upon geomagnetic activity but also dependent on solar wind parameters with velocity and southward interplanetary magnetic field Bs (Bz < 0), evidently the most influential solar wind parameters. The largest peak chorus intensities in the order of 50 pT are observed during active conditions, high solar wind velocities, low solar wind densities, high pressures, and high Bs. The average chorus intensities are more extensive and stronger for lower band chorus than the corresponding upper band chorus.