A Unique Case of Complex Interaction Between MSTIDs and Mid‐Latitude Field‐Aligned Plasma Depletions Over Geomagnetic Low‐Mid Latitude Transition Region

Abstract

On a geomagnetically quiet night of July 07, 2018, the allsky imager at Hanle, Leh Ladakh (32.7°N, 78.9°E; Mlat. ∼24.1°N), India captured a number of plasma structures in O (1D) 630.0 nm airglow emission. In a short observational period of around 3 h, two different medium scale traveling ionospheric disturbances and two different mid‐latitude plasma depletions were observed. The most interesting aspect of the night was the drastic difference in the behavior of the two plasma depletions, which simultaneously existed within the imager's field of view for a long time. One of the plasma depletions, which we have termed as mid‐latitude field‐aligned plasma depletion, was nearly field aligned, drifted westward very slowly and became more prominent later in the night. The other depletion showed a much more ambiguous behavior with large reduction in its drift as well as significant change in its orientation relative to the geomagnetic meridian. In the present study, we have tried to explain this contrasting behavior in two different scenarios and have discussed arguments supporting each scenario along with their limitations. These observations are particularly useful considering the location of Hanle, which lies at a transition of geomagnetically low‐mid latitudes, which are governed by different electrodynamics.

Interaction Between an EMSTID and an EPB in the EIA Crest Region Over China

“…It is thus extremely rare for an EMSTID that directly encounters an EPB. Yadav et al (2021) recently reported a unique case of a complex interaction between EMSTIDs and mid-latitude field-aligned plasma depletions over the geomagnetic low-mid latitude transition regions of India. However, either an extended part of the EMSTID or an EPB depletion could be the source of those mid-latitude field-aligned plasma depletions in their study.…”

A Case Study on the Interaction Between MSTIDs' Fronts, Their Dissipation, and a Curious Case of MSTID's Rotation Over Geomagnetic Low‐Mid Latitude Transition Region

“…In all the cases, the polarization electric field within the MSTIDs' fronts played a role in the interaction process. Of late, simultaneous existence of two different MSTIDs has been reported from the same location of Hanle (Rathi et al., 2021; Yadav, Rathi, Sarkhel, et al., 2021), but in these cases, there was no interaction between these coexisting MSTIDs. Wu et al.…”

“…MSTIDs, plasma bubbles, etc. in the F region over midlatitudes (Otsuka et al., 2012; Rathi et al., 2021; Wu et al., 2021; Yadav, Rathi, Gaur, et al., 2021; Yadav, Rathi, Sarkhel, et al., 2021). Still fewer studies have reported interaction between such coexisting plasma structures (Otsuka et al., 2012; Wu et al., 2021; Yadav, Rathi, Gaur, et al., 2021).…”

“…(2021); Yadav, Rathi, Sarkhel, et al. (2021) observed interactions between different plasma structures, including MSTIDs, from the same location. This paper reports an exciting event consisting of multiple phenomena, which started with an interaction between plasma depleted fronts of MSTIDs traveling in the southwest direction.…”

Evidence for the In‐Situ Generation of Plasma Depletion Structures Over the Transition Region of Geomagnetic Low‐Mid Latitude

“…(2021), and Yadav, Rathi, Sarkhel, et al. (2021) observed a mid‐latitude spread‐F/field aligned plasma structures over the low‐mid‐latitude transition region, Hanle and argued the possible supporting mechanism. However, to the best of our knowledge, there is no observational evidence that shows the onset and evolution of plasma depletion in the FOV of an airglow imager over the geomagnetic low‐mid latitude transition region.…”