Penetration electric fields: Efficiency and characteristic time scale
Penetration electric fields: Efficiency and characteristic time scale
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DOI：
10.1016/j.jastp.2006.08.016
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发表时间：
2007-07
影响因子：
1.9
通讯作者：
Chaosong Huang;S. Sazykin;J. Chau;N. Maruyama;M. Kelley
中科院分区：
文献类型：
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作者：
Chaosong Huang;S. Sazykin;J. Chau;N. Maruyama;M. Kelley
行星际电场（IEF）对中低纬度电离层的穿透已经进行了近40年的研究。以往的研究大多集中在行星际和电离层电场扰动之间的相关性上。除了Kelley等人[2003]最近的一个案例分析外，很少有人关注定量关系。太阳风电场对磁层/电离层系统的渗透。地球物理学报30(4),1158。doi: 10.1029/2002 gl016321]。本文给出了IEF穿透日侧赤道电离层效率的统计结果；效率定义为赤道电离层电场变化量与电离层电场变化量之比。Jicamarca非相干散射雷达自2001年起以相干散射方式连续工作，统计数据采用赤道电离层电场的雷达数据。在数据统计的基础上，我们得出了渗透效率的经验值为9.6%。我们将这一经验公式应用于风暴时穿透电场在较长时间内向南行星际磁场的观测和数值模拟。公式的预测与实例研究和磁层-电离层-热层耦合系统的第一性原理模拟结果很好地吻合。我们的结论是，在磁暴的主要阶段，IEF可以连续穿透到低纬度电离层，而没有明显的衰减。
Penetration of the interplanetary electric field (IEF) to the middle- and low-latitude ionosphere has been investigated for nearly four decades. Most previous studies focused on the correlation between the interplanetary and ionospheric electric field perturbations. Very little attention has been paid to a quantitative relationship except for a recent case analysis by Kelley et al. [2003. Penetration of the solar wind electric field into the magnetosphere/ionosphere system. Geophysical Research Letters 30(4), 1158. doi:10.1029/2002GL016321]. In this paper, we present a statistical result of the efficiency of IEF penetration to the dayside equatorial ionosphere; the efficiency is defined as the ratio of the change of the equatorial ionospheric electric field to the change of the IEF. The Jicamarca incoherent scatter radar has made continuous operation with a coherent scatter mode since 2001, and the radar data of equatorial ionospheric electric fields are used in our statistics. On the basis of data statistics, we derive an empirical value of 9.6% for the efficiency of penetration. We apply this empirical formula to the observations and numerical simulations of storm-time penetration electric fields over a prolonged interval of southward interplanetary magnetic field. The prediction of the formula is in good agreement with case studies and with results from first-principle simulations of the coupled magnetosphere–ionosphere–thermosphere system. We conclude that the IEF can continuously penetrate to the low-latitude ionosphere without significant attenuation for many hours during the main phase of magnetic storms.