Observations and Modeling Investigations of Ionospheric Response to 23–24 April 2023, G4‐Class Geomagnetic Storm Over Indian Sector
Abstract This study explores the ionospheric response over the Indian sector to the G4‐class geomagnetic storm of 23–24 April 2023. Utilizing multi‐instrument observations and SAMI2 modeling, ionospheric behavior was examined during the storm's main phase (17:41 UT, 23 April–04:03 UT, April 24)...
Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Wiley
2025-06-01
|
| Series: | Space Weather |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2024SW004253 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | Abstract This study explores the ionospheric response over the Indian sector to the G4‐class geomagnetic storm of 23–24 April 2023. Utilizing multi‐instrument observations and SAMI2 modeling, ionospheric behavior was examined during the storm's main phase (17:41 UT, 23 April–04:03 UT, April 24) and the recovery phase (04:03 UT–22:44 UT, 24 April). During the main phase, ionosonde data from Tirunelveli showed rapid F‐layer height (h’F) variations driven by westward and eastward prompt penetration electric fields (PPEFs). The westward PPEF, induced by undershielding, led to an initial decrease in h’F followed by an increase, suppressing pre‐existing Equatorial Plasma Bubbles (EPBs) within two hours of the storm's onset. Despite a late‐night rise in h’F due to overshielding, no new EPB formed. The recovery phase exhibited a positive storm effect at low latitudes and a negative effect at higher latitudes, linked to disturbance dynamo electric fields (DDEFs) and thermospheric composition changes (Σ[O]/[N2] ratio). Large‐scale traveling ionospheric disturbances were clearly evident in GNSS TEC and ionosonde data, with a ∼2‐hr period, ∼2,450 km wavelength, and ∼340 m/s equatorward speed, likely driven by auroral/Joule heating‐induced atmospheric gravity waves. On 24 April, the westward DDEF suppressed the daytime equatorial ionization anomaly (EIA) and inhibited post‐sunset EPBs, while eastward DDEF increased h’F in the post‐midnight without EPB formation. We speculate that this absence might be due to a lack of seeding mechanisms. SAMI2 simulations incorporating E × B drift data reproduced several storm‐time features in the main and recovery phases. |
|---|---|
| ISSN: | 1542-7390 |