The Role of Storm Time Electrodynamics in Suppressing the Equatorial Plasma Bubble Development in the Recovery Phase of a Geomagnetic Storm

• Published in: Journal of geophysical research. Space physics 2018-03, Vol.123 (3), p.2336-2350
• Main Authors: Sripathi, S., Banola, S., Emperumal, K., Suneel Kumar, B., Radicella, Sandro M.
• Format: Article
• Language: English
• Subjects: Counter electrojet; Electric fields; Electrodynamics; Electrojets; Equatorial electrojet; Equatorial ionosphere; equatorial plasma bubbles; Es layers; F3 layers; Geomagnetic storms; Geomagnetism; Interplanetary magnetic field; Ionosphere; ionospheric electrodynamics; ionospheric irregularities; Latitude; Magnetic fields; Magnetic storms; Magnetospheres; Recovery; Signatures; Spread F; Storms; Sunset; Wind
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1002/2017JA024956

We investigate the role of storm time electrodynamics in suppressing the equatorial plasma bubble (EPB) development using multi‐instruments over India during a moderate geomagnetic storm that occurred on 2 October 2013 where Dst minimum reached ~−80 nT. This storm produced unique signatures in the equatorial ionosphere such that equatorial electrojet strength showed signatures of an abrupt increase of its strength to 150 nT and occurrence of episodes of counter electrojet events. During the main phase of the storm, the interplanetary magnetic field Bz is well correlated with the variations in the equatorial electrojet/counter electrojet suggesting the role of undershielding/overshielding electric fields of magnetospheric origin. Further, observations showed the presence of strong F3 layers at multiple times at multiple stations due to undershielding electric field. Interestingly, we observed simultaneous presence of F3 layers and suppression of EPBs in the dusk sector during the recovery phase. While strong EPBs were observed before and after the day of the geomagnetic storm, suppression of the EPBs on the storm day during “spread F season” is intriguing. Our further analysis using low‐latitude station, Hyderabad, during the time of prereversal enhancement suggests that intense Esb layers were observed on the storm day but were absent/weak on quiet days. Based on these results, we suggest that the altitude/latitude variation of disturbance dynamo electric fields/disturbance winds may be responsible for simultaneous detection of F3 layers, occurrence of low‐latitude Es layers, and suppression of EPBs during the storm day along the sunset terminator. Key Points Occurrence of simultaneous F3 layers at equator and Esb layers at low latitude but suppression of EPBs in the dusk sector in the recovery phase of a magnetic storm Intense Esb layers at low latitude when EPBs are suppressed on the storm day but are weak when EPBs occur on quiet days The altitude/latitude variation of DD electric fields in the sunset sector may be responsible for these results