The Evolution of Magnetic Rayleigh–Taylor Unstable Plumes and Hybrid KH-RT Instability into a Loop-like Eruptive Prominence

Abstract

MRT-unstable plumes are observed in a loop-like eruptive prominence using Solar Dynamic Observatory/Atmospheric Imaging Assembly observations. The small-scale cavities are developed within the prominence, where perturbations trigger dark plumes (P1 and P2) propagating with speeds of 35–46 km s−1. The self-similar plume formation initially shows the growth of a linear MRT-unstable plume (P1), and thereafter the evolution of a nonlinear single-mode MRT-unstable second plume (P2). A differential emission measure analysis shows that plumes are less dense and hotter than the prominence. We have estimated the observational growth rate for both plumes as 1.32 ± 0.29 × 10−3 s−1 and 1.48 ± 0.29 × 10−3 s−1, respectively, which are comparable to the estimated theoretical growth rate (1.95 × 10−3 s−1). The nonlinear phase of an MRT-unstable plume (P2) may collapse via a Kelvin–Helmholtz vortex formation in the downfalling plasma. Later, a plasma thread is evident in the rising segment of this prominence. It may be associated with the tangled field and Rayleigh–Taylor instability. The tangled field initiates shearing at the prominence–cavity boundary. Due to this shear motion, the plasma downfall occurred at the right part of the prominence–cavity boundary. It triggers the characteristic KH unstable vortices and MRT-unstable plasma bubbles propagating at different speeds and merging with each other. The shear motion and lateral plasma downfall may initiate hybrid KH-RT instability there.

Chromospheric Heating by Magnetohydrodynamic Waves and Instabilities

“…Additionally, Khomenko et al(2014a) showed that the non-ideal, partially ionized chromospheric plasma with resistive and ambipolar diffusion taken into account experiences larger growth rate of the RT instability (RTI), faster plasma flows, rapid downflows, evolution of the high temperature bubbles, and the asymmetry between large rising bubbles and small-scale down-flowing fingers, compared to the plasma evolution in the framework of ideal MHD. Such dynamical plasma processes, elevated temperatures, and RT features are well observed by Mishra and Srivastava (2019). Usually, the ideal MHD is sufficient to explain the RT instability.…”

“…A representative evolution of RT instability in the solar prominence system, resulting from the above equation, is shown in Figure 7 both in the observations (left) and numerical modeling (right). The evolution of the bubbles and plumes are characteristic features associated with the RT instabilities evolved in the solar chromospheric prominence plasma (Berger et al 2010;Hillier et al 2012;Mishra and Srivastava 2019).…”

“…While wave dynamics is potentially influenced by the structured chromosphere, there may be certain physical conditions that may lead to a subsequent growth of the perturbations in the form of various instabilities. The most common instabilities that are observed and studied in the large-scale chromospheric structures "(e.g., solar prominences)" are driven by respectively the gravity and sheared flow: (i) Rayleigh-Taylor (RT) and (ii) Kelvin-Helmholtz (KH) instabilities (Berger et al 2008;Ryutova et al 2010;Berger et al 2010;Hillier et al 2011;Berger et al 2017;Mishra and Srivastava 2019). The RT instability was originally proposed by Rayleigh (1899) and Taylor(1950) to explain the growth of small-amplitude perturbations at the interface between two fluids.…”

“…How do these contribute to the fast component of the solar wind at higher altitudes? Despite significant observational and theoretical developments over two decades on magnetic waves, shocks, instabilities, and formation of the jets/flows, their respective roles or inter-relationships in a variety of chromospheric magnetic structures are not yet fully understood (e.g., Kudoh and Shibata 1999;De Pontieu et al 2004;Shibata et al 2007;Nishizuka et al 2011;Iijima and Yokoyama 2015;Zhelyazkov et al 2015;Brady and Arber 2016;Kuźma et al 2017;Kayshap et al 2018b;Mishra and Srivastava 2019;Wójcik et al 2019;Wang and Yokoyama 2020;Zaqarashvili et al 2020).…”

“…The evolution of the bubbles and plumes are characteristic features associated with the RT instabilities evolved in the solar chromospheric prominence plasma (T. E. Berger et al., 2010; Hillier et al., 2012; Mishra & Srivastava, 2019).…”