This paper presents the equatorial ionospheric response to eleven strong-to-severe geomagnetic storms that occurred during the period 2000-2005, the declining phase of the solar cycle 23. The analysis has been performed using the global ion density plots of Defense Meteorological Satellite Program (DMSP). Observations show that for about 91% of the cases, post-sunset equatorial irregularities occurred within 3h from the time of northward to southward transition of the Interplanetary Magnetic Field (IMF) clock angle, thus bringing out the importance of the role played by IMF By in the process of Prompt Penetration of Electric Field (PPEF) in addition to the IMF Bz. This is an improvement from the previously reported (Ray et al.,2015) 4h window of ESF generation from the southward IMF Bz crossing -10 nT.

中文翻译：

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电离层对 2000-2005 年强地磁风暴的响应：IMF 时钟角度视角

本文介绍了赤道电离层对 2000-2005 年期间发生的 11 次强到严重地磁暴的响应，即太阳活动周期的下降阶段 23。该分析是使用国防气象卫星计划的全球离子密度图进行的(DMSP)。观测表明，在大约 91% 的情况下，在行星际磁场 (IMF) 时钟角向北向南过渡的 3 小时内发生了日落后的赤道不规则现象，由此可以看出 IMF 所发挥的作用的重要性。除了 IMF Bz 之外，在快速穿透电场 (PPEF) 的过程中。这是对先前报道的（Ray 等人，2015 年）从南向 IMF Bz 跨越 -10 nT 生成 ESF 的 4 小时窗口的改进。