2D MHD and 1D HD models of a solar flare -- a comprehensive comparison of the results

TL;DR

This study compares 1D hydrodynamic and 2D magnetohydrodynamic models of solar flares to understand energy redistribution and plasma dynamics, demonstrating that 2D models effectively approximate observed flaring structures despite simplifications.

Contribution

The paper develops and compares 1D and 2D models of solar flaring loops, highlighting the effectiveness of 2D models in replicating observational features of flares.

Findings

2D models can approximate multi-thread flare structures with a filling factor of one.

Despite simplifications, 2D models successfully replicate observed plasma dynamics.

Energy redistribution mechanisms differ between 1D and 2D models, affecting their accuracy.

Abstract

Without any doubt solar flaring loops possess a multi-thread internal structure that is poorly resolved and there are no means to observe heating episodes and thermodynamic evolution of the individual threads. These limitations cause fundamental problems in numerical modelling of flaring loops, such as selection of a structure and a number of threads, and an implementation of a proper model of the energy deposition process. A set of 1D hydrodynamic and 2D magnetohydrodynamic models of a flaring loop are developed to compare energy redistribution and plasma dynamics in the course of a prototypical solar flare. Basic parameters of the modeled loop are set according to the progenitor M1.8 flare recorded in the AR10126 on September 20, 2002 between 09:21 UT and 09:50 UT. The non-ideal 1D models include thermal conduction and radiative losses of the optically thin plasma as energy loss mechanisms, while the non-ideal 2D models take into account viscosity and thermal conduction as energy loss mechanisms only. The 2D models have a continuous distribution of the parameters of the plasma across the loop, and are powered by varying in time and space along and across the loop heating flux. We show that such 2D models are a borderline case of a multi-thread internal structure of the flaring loop, with a filling factor equal to one. Despite the assumptions used in applied 2D models, their overall success in replicating the observations suggests that they can be adopted as a correct approximation of the observed flaring structures.