Equatorial electrojet as part of the global circuit: a case-study from the IEEY
Equatorial electrojet as part of the global circuit: a case-study from the IEEY
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DOI：
10.1007/s00585-998-0698-1
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发表时间：
1998-06
影响因子：
1.9
通讯作者：
A. Kobea;C. Amory-Mazaudier;J. Do;H. Lühr;E. Houngninou;J. Vassal;E. Blanc;J. Curto
中科院分区：
文献类型：
--
作者：
A. Kobea;C. Amory-Mazaudier;J. Do;H. Lühr;E. Houngninou;J. Vassal;E. Blanc;J. Curto
地磁风暴时间变化经常相干地发生在高纬度和日侧倾角赤道，在那里它们影响正常的东向Sq场。本文分析了1993年5月27日国际赤道电急流年（IEEEY）实验期间发生的磁暴的地面磁场和电离层电动力学资料。对极光、中纬度和赤道地面场和电离层电动力学数据的这种风暴特征分析导致确定赤道电急流（EEJ）对大规模极光返回电流的敏感响应：这种响应包括在日出前几个小时内向东电场的变化（0400-0600 UT）与高纬度、中纬度和赤道纬度Hdecrease以及EEJ不规则性在时间间隔0800-0950 UT之间的消失相一致。在日出前的h 'F的变化之后，观测到的foF 2的增加揭示了由高纬度穿透电场引起的赤道电离异常（EIA）的增强。这些不规则性的加强证明了多普勒频率的增加跟踪赤道处的H分量，该分量在0800 UT左右迅速增加。在赤道观测到的电离层变化是下列分量之和：SR、DP、DR、DCF和DT.关键词.赤道电射流·磁层-电离层相互作用·电场和电流·极光电离层·电离层扰动
Geomagnetic storm-time variations often occur coherently at high latitude and the day-side dip equator where they affect the normal eastward Sq field. This paper presents an analysis of ground magnetic field and ionospheric electrodynamic data related to the geomagnetic storm which occured on 27 May 1993 during the International Equatorial Electrojet Year (IEEY) experiment. This storm-signature analysis on the auroral, mid-latitude and equatorial ground field and ionospheric electrodynamic data leads to the identification of a sensitive response of the equatorial electrojet (EEJ) to large-scale auroral return current: this response consists in a change of the eastward electric field during the pre-sunrise hours (0400-0600 UT) coherently to the high-, mid-, and equatorial-latitudeHdecrease and the disappearance of the EEJ irregularities between the time-interval 0800-0950 UT. Subsequent to the change in h'F during pre-sunrise hours, the observed foF2 increase revealed an enhancement of the equatorial ionization anomaly (EIA) caused by the high-latitude penetrating electric field. The strengthening of these irregularities attested by the Doppler frequency increase tracks theHcomponent at the equator which undergoes a rapid increase around 0800 UT. The ∆Hvariations observed at the equator are the sum of the following components:SR,DP,DR,DCFandDT.Keywords.Equatorial electrojet · Magnetosphere-ionosphere interactions · Electric fields and currents · Auroral ionosphere · Ionospheric disturbances