Numerical modeling of prominence formation from reconnection to radiative condensation
Abstract
We briefly review recent progress in numerical modeling for prominence formation and introduce our model, reconnection-condensation model. Origin of cool dense plasmas and mechanism of mass maintenance in the hot tenuous corona is one of the most important subjects in studies of solar prominences. Radiative cooling condensation is a promising process to supply mass for prominences. The formation mechanism of fine structures and turbulence in prominence and their physical role for mass condensation are also unclear.Numerical modeling is useful to investigate these issues. In previous numerical studies, it is known that chromospheric evaporation driven by parameterized footpoint heating leads to in-situ coronal condensation. The evaporation-condensation model was demonstrated in a three-dimensional flux rope structure using magnetohydrodynamic (MHD) simulations including thermal conduction and radiative cooling, and succeeded in reproducing prominences with fine structures by fragmented condensations. Despite these efforts, the issue on unclear origin of the footpoint heating still remains.We attempt to consider a different process leading to radiative condensation. In observations, prominences always appear along polarity inversion lines, suggesting that cancelation or reconnection must be related to radiative condensation. In the previous simulations on radiative condensation, self-consistent multi-dimensional reconnection process were absent. We propose reconnection-condensation model and demonstrate it using three-dimensional MHD simulations including nonlinear anisotropic thermal conduction and optically thin radiative cooling. In our model, a flux rope is created by reconnection via converging footpoint motion. By elevation of dense coronal plasmas and topological change in coronal magnetic fields, radiative condensation is triggered inside the flux rope. Our results show clear link between reconnection and radiative condensation, and suggest that evaporation is not always necessary.Recently, we improved the model to include dynamic fine structures by the Rayleigh-Taylor instability. We found that mass condensation rate is enhanced to balance with mass drainage rate by coupling with the Rayleigh-Taylor instability. We compare the simulation results with observations and discuss remained issues in numerical modeling for prominence formation.
- Publication:
-
42nd COSPAR Scientific Assembly
- Pub Date:
- July 2018
- Bibcode:
- 2018cosp...42E1673K