Case study of an Equatorial Plasma Bubble Event investigated by multiple ground-based instruments at low latitudes over China

Abstract

An enhanced equatorward wind destabilized the Rayleigh-Taylor instability that forced several EPB depletions seeded by an LSWS to surge poleward. q Observed and analyzed were brightness structures of airglow depletions filled by high-density plasma transported by an enhanced poleward wind associated with a brightness wave. q A mechanism of LSWS-blob connection is proposed to explain the plasma blobs.

Multi‐Source Perturbations in the Evolution of a Low‐Latitudinal Equatorial Plasma Bubble Event Occurred Over China

“…As will be analyzed later, the disappearance of this equatorward wind at postmidnight at the Fuke/Sanya station is most likely offset by a poleward wind associated with a passing‐by nighttime temperature maximum (TM; Colerico & Mendillo, 2002) from the lower latitudes. Sun, Xu, Zhu, Yuan, and Zhao (2021) previously verified this poleward wind by analyzing relative variations between ionospheric heights observed by a chain of digisondes and meridional winds measured by a Fabry‐Perot interferometer in the Chinese sectors. It should be noted that LM station located near the magnetic conjugate point of BJ station also showed significant uplift between 13 and 17 UT.…”

“…Previous studies by Sun et al. (2017) and Sun, Xu, Zhu, Yuan, and Zhao (2021) found this kind of brightness region is the true plasma phenomenon that has an enhanced plasma density than the surrounding ionosphere. These brightness structures were early called “blobs” by Pimenta et al.…”

“…Second, two other patchy regions (marked with "PR1-PR2") with brighter airglow intensity appeared within the EIA region. Previous studies by Sun et al (2017) and Sun, Xu, Zhu, Yuan, and Zhao (2021) found this kind of brightness region is the true plasma phenomenon that has an enhanced plasma density than the surrounding ionosphere. These brightness structures were early called "blobs" by Pimenta et al (2004Pimenta et al ( , 2007.…”

“…There are few studies (e.g., Ajith et al., 2016; Dao et al., 2016, 2017; Krall et al., 2021; Sun, Xu, Zhu, Yuan, & Zhao, 2021; Yokoyama et al., 2011) found that equatorward neutral winds can also initialize freshly‐generated EPBs around midnight. Those studies suggest that the uplift of the ionosphere by equatorward neutral winds could lead to a decrease in the frequency of ion‐neutral collision, resulting in an increasing gravity‐driven eastward electric current that initializes EPBs above the geomagnetic equator by the RTI (Huba & Krall, 2013; Nishioka et al., 2012).…”

Multi-source Perturbations in the Evolution of a Low-latitudinal Equatorial Plasma Bubble Event Occurred over China

“…Few studies (e.g., Yokoyama et al, 2011;Ajith et al, 2016;Dao et al, 2016Dao et al, , 2017Sun et al, 2021a) found an equatorward neutral wind (ENW) can also initialize EPBs, especially those near midnight. Those studies suggested that the uplift of the ionosphere by an ENW could cause a decreasing ion-neutral collision frequency, resulting in an increasing gravity-driven eastward electric current that can initialize EPBs above the geomagnetic equator (Nishioka et al, 2012;Huba & Krall, 2013).…”