This work analyzes the geo-effectiveness of Coronal Mass Ejection- (CME-) induced storms by investigating the responses of ionospheric Vertical Total Electron Content (VTEC) and the Equatorial Ionization Anomaly (EIA) over the Indian sector to two storms. One of the storms occurred on February 19, 2014 (SYM-H: −120 nT), while the other occurred on June 23, 2015 (SYM-H: −204 nT). Both storms were driven by full halo CMEs. Global TEC maps were used to characterize VTEC variations during the storms. June 23, 2015 storm was characterized with stronger solar progenitors, right from its origin, although the VTEC response to the storm was not influenced by their strong progenitors. The CMEs that caused the selected storms are large (Halo CMEs). We inferred that irrespective of the strength of solar origin of a storm, the response of ionization distribution over equatorial and low-latitude regions to it depends on the season of storm occurrence, local time of the storm onset, and PPEF orientation. From the VTEC variations for the three Indian stations namely, Trivandrum (geographic latitude: 8.52°N, geographic longitude: 76.94°E, magnetic latitude: 0.37°N), Hyderabad (17.39°N, 78.49°E, 10.15°N) and Delhi (28.70°N, 77.10°E, 22.70°N), we observed that EIA disturbances were more prominent over Hyderabad than over Delhi. The February 19, 2014 storm was characterized by a localized EIA crest at latitude a little above Hyderabad, while in June 23, 2015 storm localized EIA crest was observed directly on Hyderabad. IRI-2016 model generally underestimated VTEC at the three Indian equatorial and low-latitude locations. Solar cycle 24 was characterized with low heliospheric pressure due to its weak polar field strength. The lower pressure allowed CMEs to expand greatly as they transit through space. As they expand, the strengths of the magnetic field inside them decrease, and such lower-strength magnetic fields cause geomagnetic storms that are less geoeffective, even when their solar/interplanetary progenitors are strong and healthy. This associated weak polar field strength of solar cycle 24 caused weak fountain effect with the attendant inability to exhibit storm-time super-fountain effect in the dayside of the equatorial/low-latitude regions.

这项工作通过调查电离层垂直总电子含量 (VTEC) 和赤道电离异常 (EIA) 对印度地区的两次风暴的响应，分析了日冕物质抛射 (CME) 诱发风暴的地球有效性。其中一场风暴发生在 2014 年 2 月 19 日（SYM-H：-120 nT），而另一场发生在 2015 年 6 月 23 日（SYM-H：-204 nT）。这两场风暴都是由全光环 CME 驱动的。全球 TEC 地图用于表征风暴期间的 VTEC 变化。2015 年 6 月 23 日风暴的特点是从其起源开始就具有更强的太阳前身，尽管 VTEC 对风暴的反应不受其强大前身的影响。引起选定风暴的 CME 很大（Halo CME）。我们推断，无论风暴起源于太阳的强度如何，赤道和低纬度地区电离分布对其的响应取决于风暴发生的季节、风暴发生的当地时间和 PPEF 方向。来自三个印度站的 VTEC 变化，即特里凡得琅（地理纬度：8.52°N，地理经度：76.94°E，磁纬度：0.37°N）、海得拉巴（17.39°N、78.49°E、10.15°N）和德里（北纬 28.70°、东经 77.10°、北纬 22.70°），我们观察到海得拉巴的 EIA 扰动比德里更突出。2014 年 2 月 19 日风暴的特点是在海得拉巴稍上纬度出现局部 EIA 波峰，而 2015 年 6 月 23 日直接在海得拉巴观察到局部 EIA 波峰。IRI-2016 模型普遍低估了印度三个赤道和低纬度地区的 VTEC。由于极场强度较弱，太阳活动周期 24 的特点是日球层压力低。较低的压力使 CME 在穿越太空时可以大大扩展。随着它们的扩张，它们内部的磁场强度会减弱，这种强度较低的磁场会导致地磁风暴的地球效应降低，即使它们的太阳/行星际祖先强大而健康。太阳活动周期 24 的这种相关的弱极场强度导致了弱喷泉效应，随之而来的是无法在赤道/低纬度地区的白天表现出风暴时的超级喷泉效应。这种强度较低的磁场会导致地磁风暴对地球的影响较小，即使它们的太阳/行星际祖先强大而健康。太阳活动周期 24 的这种相关的弱极场强度导致了弱喷泉效应，随之而来的是无法在赤道/低纬度地区的白天表现出风暴时的超级喷泉效应。这种强度较低的磁场会导致地磁风暴对地球的影响较小，即使它们的太阳/行星际祖先强大而健康。太阳活动周期 24 的这种相关的弱极场强度导致了弱喷泉效应，随之而来的是无法在赤道/低纬度地区的白天表现出风暴时的超级喷泉效应。