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

Abstract

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.

Extreme Poleward Expanding Super Plasma Bubbles Over Asia‐Pacific Region Triggered by Tonga Volcano Eruption During the Recovery‐Phase of Geomagnetic Storm

“…One of such major external factors controlling the occurrence of EPBs is geomagnetic storm (hereafter, storm), either amplifying or suppressing the bubble generation (Rajesh, Lin, Chen, Chen, et al., 2017; Rastogi et al., 1981; Whalen, 2002; R. W. Wright et al., 1956). The impact of prompt penetration and/or disturbance dynamo electric field, either aids or suppresses the pre‐reversal enhancement (PRE), leading to the generation/inhibition of bubbles, and occasionally in the post‐midnight irregularities (Aarons, 1991; Rajesh, Lin, Chen, Lin, et al., 2017; Sripathi et al., 2018). Occasionally, strong prompt penetration electric fields generate super plasma bubbles, reaching much higher latitudes (Aa et al., 2018; Cherniak & Zakharenkova, 2016; Ma & Maruyama, 2006).…”

Solar Cycle Dependence and Seasonal Variation of Ionospheric Radio Scintillations

“…This ionization is located at the background of the equatorial plasma bubbles, which are formed after sunset, when the prereversal enhancement of the eastward electric field takes place and enables the growing of Rayleigh-Taylor instabilities. These instabilities favor the intensification of the irregularities, especially at the EIA crests, and the amplitude scintillations occur more frequently [13][14][15][16].…”

Climatology of ionospheric amplitude scintillation on GNSS signals at south American sector during solar cycle 24

“…These regions are in correspondence with the expected position of the crests of EIA, that are due to the plasma accumulation formed mainly by the removal of plasma around the magnetic equator due to the ExB itself (Balan et al, 2018). In the post-sunset hours, the more probable seed to EPBs is the pre-reversal enhancement (PRE) of the eastward electric field, and there is a consequent intensification of the crests of the ExB drift, creating favorable conditions for the growth of Rayleigh-Taylor instabilities (Spogli et al, 2016;Sripathi et al, 2018;Li et al, 2020). There is an asymmetry between northern and southern crests of the EIA, resulting in more frequent scintillations and with larger S4 occurrence, most likely attributed to the SAMA, where particles from the inner Van Allen radiation belt precipitate into the atmosphere, due to the week geomagnetic field over the region (Abdu et al, 2005).…”

“…The post-sunset scintillation at NAT was inhibited on 01 November and at CUI, on 31 October and 01 November. According to the empirical rule, known as "Aaron criteria", when the disturbance occurs in the afternoon, before PRE, there is an inhibition of irregularities (Aarons, 1991;Li et al, 2008;Spogli et al, 2016;Sripathi et al, 2018), which explains the scintillation inhibition in the post-sunset on 01 November at both stations. In this case, the long-lasting negative IMF-Bz condition, under which no PPEF event occur, and the large values of AE, triggered a significant Joule/particle heating at high-latitude, resulting in DDEF events.…”