Simulations of Prominece Formation in the Magnetized Solar Corona by Chromospheric Heating

Xia Chun, School of Astronomy and Space Science, Nanjing University
Chen Pengfei, School of Astronomy and Space Science, Nanjing University
Keppens Rony, Centre for Plasma Astrophysics, K.U. Leuven

Abstract
Starting from a realistically sheared magnetic arcade connecting the chromospheric, transition region to coronal plasma, we simulate the in situ formation and sustained growth of a quiescent prominence in the solar corona. Contrary to previous works, our model captures all phases of the formation of prominence condensations, including the loss of thermal equilibrium, its successive growth in height and width to macroscopic dimensions, and the gradual bending of the arched loops into dipped loops, as a result of the mass accumulation. Our 2.5 dimensional, fully thermodynamically and magnetohydrodynamically consistent model mimics the magnetic topology of normal-polarity prominences above a photospheric neutral line, and results in a curtain-like prominence above the neutral line through which the ultimately dipped magnetic field lines protrude at an acute angle. The formation results from concentrated heating in the chromosphere, followed by plasma evaporation and later rapid condensation in the corona due to thermal instability, as verified by linear instability criteria. Concentrated heating in the lower atmosphere evaporates plasma from below to accumulate at the top of coronal loops and supply mass to the later prominence constantly. This is the first evaporation–condensation model study where we can demonstrate how the formed prominence stays in a force balanced state, which can be compared to the Kippenhahn–Schluter type magnetohydrostatic model, all in a finite low-beta corona.