Response of Equatorial Ionization in Indian Longitudes to HSSW Driven Geomagnetic Storm

The paper reports the effects of a moderate High Speed Solar Wind (HSSW) driven Corotating Interaction Region (CIR) geomagnetic storm (minimum Dst ≤ -53 nT) on the ionosphere at Hyderabad (17.42°N, 78.55°E geographic, 8.93°N, 152.65°E geomagnetic) during August 4-8, 2019. Hyderabad is situated at geophysically sensitive Equatorial Ionization Anomaly (EIA) region between geomagnetic equator and northern crest of EIA. The results yield positive enhancement of Total Electron Content (TEC) during the main phase of the storm (August 5, 2019, increment of VTEC: 8.17 TECU). The effects of Disturbed Dynamo Electric Field (DDEF) were also observed during the recovery phase of the storm (August 6, 2019, decrement of VTEC: 7.56 TECU). Another TEC enhancement was observed during the recovery phase of the storm (August 7, 2019, increment of VTEC: 4.25 TECU). This could possibly be explained by the day-to-day variabilities of TEC at low latitudes and the impact of fading geomagnetic storm intensity coupled with strong solar wind.