Rotational Flows in Solar Coronal Flux Rope Cavities

Abstract

We present a 2.5D magnetohydrodynamic simulation of a systematically rotating prominence inside its coronal cavity using the open-source MPI-AMRVAC code. Our simulation starts from a nonadiabatic, gravitationally stratified corona, permeated with a sheared arcade magnetic structure. The flux rope (FR) is formed through converging and shearing footpoints driving, simultaneously applying randomized heating at the bottom. The latter induces a left–right asymmetry of temperature and density distributions with respect to the polarity inversion line. This asymmetry drives flows along the loops before the FR formation, which gets converted to net rotational motions upon reconnection of the field lines. As the thermal instability within the FR develops, angular momentum conservation about its axis leads to a systematic rotation of both hot coronal and cold condensed plasma. The initial rotational velocity exceeds 60 km s−1. The synthesized images confirm the simultaneous rotations of the coronal plasma seen in 211 and 193 Å and condensations seen in 304 Å. Furthermore, the formation of the dark cavity is evident in 211 and 193 Å images. Our numerical experiment is inspired by observations of so-called giant solar prominence tornadoes and reveals that asymmetric FR formation can be crucial in triggering rotational motions. We reproduce observed spinning motions inside the coronal cavity, augmenting our understanding of the complex dynamics of rotating prominences.

Radiative loss and ion-neutral collisional effects in astrophysical plasmas

“…At the same time, many recent works [e.g. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] support the original claim by Parker [17] that thermal instability is a fundamental process that can trigger in situ condensations, like prominences and coronal rain in the solar atmosphere, but also denser clumps in galactic winds, or in other astrophysical contexts [18][19][20]. For this reason, the linear mode which grows exponentially due to the energy loss is usually called 'thermal' or 'condensation' mode (see [21]).…”

Energetics of a Solar Flare and a Coronal Mass Ejection Generated by a Hot Channel Eruption

“…A magnetic flux rope (MFR) is composed of a group of twisted magnetic field lines wrapping around a common axis (see Cheng et al 2017;Liu 2020, and references therein). The helical structure of an MFR naturally provides dips to support the dense materials in solar prominences (van Ballegooijen & Martens 1989;Okamoto et al 2008;Zhou et al 2018;Jenkins & Keppens 2021;Liakh & Keppens 2023). MFRs play a central role in driving large-scale solar eruptions, leading to flares and coronal mass ejections (CMEs; Chen 2011).…”