Magnetic field amplification and structure formation by the Rayleigh-Taylor instability

Abstract

We report our results from a set of high-resolution, two-fluid, non-linear simulations of the magnetized Rayleigh Taylor instability (RTI) at the interface between a solar prominence and the corona. These data follow results reported earlier on linear and early non-linear RTI dynamics in this environment. This paper is focused on the generation and amplification of magnetic structures by RTI. The simulations use a two-fluid model that includes collisions between neutrals and charges, including ionization and recombination, energy and momentum transfer, and frictional heating. The 2.5D magnetized RTI simulations demonstrate that in a fully developed state of RTI, a large fraction of the gravitational energy of a prominence thread can be converted into quasi-turbulent energy of the magnetic field. The RTI magnetic energy generation is further accompanied by magnetic and plasma density structure formation, including dynamic formation, break-up, and merging of current sheets and plasmoid sub-structures. The flow decoupling between neutrals and charges, as well as ionization and recombination reactions, are shown to have significant impact on the structure formation in a magnetized RTI.

Future prospects for partially ionized solar plasmas: the prominence case

“…Studies incorporating transverse conduction owing to the presence of neutrals would be necessary to understand the thermodynamic equilibrium between the corona and prominences. Only a few works [16,[39][40][41] have studied different instabilities in prominences analytically and numerically. The authors show that the presence of neutrals increases the growth rate of thermal instabilities and favours the formation of small-scale structures during the development of Rayleigh-Taylor instabilities (RTIs).…”

“…For instance, significant progress has been achieved in this direction with the implementation of the full conductivity tensor in the MANCHA3D code [42,43] but only for fully ionized plasmas. In its two-fluid version, MANCHA3D-2F, only neutral conductivity is included [39][40][41]. It is anticipated that both conductivities will be incorporated in a future version of the code.…”

“…However, [18] studied the RTI in PIP and the effect of ambipolar diffusion. More recently, [39,41,62] studied PIP in the two-fluid approximation. The authors showed that charged and neutrals decouple having a significant impact on the instability plasma dynamics.…”

The influence of thermal pressure gradients and ionization (im)balance on the ambipolar diffusion and charge-neutral drifts

“…In order to assess its influence on the drift velocity, we used 2.5D 2F simulations of RTI computed in [16,34,53]. We analysed two simulations with the parameters identical to those listed in table 1 of [16,34] with the labels P and L2 (these labels are related to the configuration of magnetic field, as explained below), but with four times more spatial resolution, as in [22,53].…”

“…Many authors include non-ideal effects derived from the presence of neutrals into their analysis to account for heating or multi-scale physics in the MF approximation (see e.g. [4,5,12,[16][17][18][19][20][21][22]). Several of those works additionally consider other non-ideal effects such as neutral viscosity, heat flux, or thin radiative losses.…”