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. Issue 4 (7th April 2022)

• Record Type: Journal Article
• Authors: Rathi, R.; Yadav, V.; Mondal, S.; Sarkhel, S.; Sunil Krishna, M. V.; Upadhayaya, A. K.; Kannaujiya, S.; Chauhan, P.
• Is Part Of: Journal of geophysical research. Volume 127:Issue 4(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-04-07
• Subjects: all‐sky airglow imager -- O(1D) 630.0 nm airglow -- MSTIDs -- Perkins' instability -- polarization electric field; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2021JA029872
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: This paper reports a rare interaction between two fronts of nighttime medium scale traveling ionospheric disturbances (MSTIDs) and associated phenomena observed over geomagnetic low‐mid latitude transition region on a geomagnetically quiet night (Ap = 5) of 21 May 2020. The event was observed for nearly 8 hours in O( 1 D) 630.0 nm airglow images captured by an all‐sky imager installed at Hanle (32.7°N, 78.9°E; Mlat. ∼24.1°N), Leh Ladakh, India and supplemented by a digisonde and a global positioning system receiver located within the imager's field of view (FOV). The images revealed a slow‐moving MSTID front being followed by a fast‐moving MSTID front, both traveling southwestward. The third front of the MSTID caught up with the second one, initiating the interaction. As a consequence, a plasma channel was created during the interaction and the MSTIDs' fronts began decaying. Subsequently, they became thin strips and later dissipated within the FOV of the imager. The polarization electric field of the merged region of the two interacting MSTIDs' fronts played a key role in creating the plasma channel. In the later hours of the night, another MSTID with a rotating front was observed, which is a rarely reported phenomenon. The horizontal gradient in the westward wind is a plausible reason for the observed rotation. This study elucidates the complex nature of geomagnetic low‐mid latitude transition region. Plain Language Summary: Medium scale traveling ionospheric disturbances (MSTIDs) are plasma depleted and rich bands propagating in the mid latitude ionospheric F region. Nighttime MSTIDs in northern hemisphere are usually aligned in the northwest to southeast direction and propagate southwestward. Despite the extensive study of MSTIDs, a few rarely reported phenomena, such as their interaction and rotation, are not well understood. A better understanding of these phenomena is crucial because of their effects on radio communication and navigation. On the night of 21 May 2020, we observed southwestward propagating multiple plasma depleted and rich MSTIDs' fronts in 630.0 nm all‐sky airglow images. The characteristics (horizontal velocity, orientation with respect to geomagnetic N‐S, and wavelength) of the observed fronts of the MSTIDs were different. As the MSTIDs' fronts propagated in the imager's field of view, the faster front caught up with the slower one, resulting in the interaction. Later on, MSTIDs' fronts decayed into thin strips and eventually disappeared. In about 1 hour after the disappearance of thin strips, another MSTID started propagating southwestward. However, its orientation and horizontal velocity decreased gradually over time. Using multi‐instrument data sets, we have explored possible mechanisms behind these phenomena. Key Points: The interaction of Medium scale traveling ionospheric disturbances (MSTIDs)' fronts resulted in creating a plasma channel followed by the decay of the MSTIDs Polarization electric field played a key role in creating the plasma channel A significant change in the orientation of one of the MSTIDs' fronts was observed