Observations of Post-flare Plasma Dynamics during an M1.0 Flare in AR11093 by SDO/AIA

TL;DR

This study combines observations of plasma motions during a solar flare with numerical simulations to understand post-flare plasma dynamics, revealing multi-temperature plasma behavior and shock-driven perturbations in the loop system.

Contribution

It provides the first combined observational and numerical analysis of multi-temperature plasma motions and shock phenomena in post-flare loops during an M1.0 flare.

Findings

Hot plasma moves faster than cool plasma in post-flare loops.

Reflected plasma intensity features indicate wave-like behavior.

Numerical simulations replicate observed plasma dynamics with impulsive heating and shock formation.

Abstract

We observe the motion of cool and hot plasma in a multi-stranded post flare loop system that evolved in the decay phase of a two ribbon M1.0 class flare in AR 11093 on 7 August 2010 using SDO/AIA 304 \AA\ and 171 \AA\ filters. The moving intensity feature and its reflected counterpart are observed in the loop system at multi-temperature. The observed hot counterpart of the plasma that probably envelopes the cool confined plasma, moves comparatively faster ($\sim$34 km s$^{-1}$) to the later (29 km s$^{-1}$) in form of the spreaded intensity feature. The propagating plasma and intensity reflect from the region of another footpoint of the loop. The subsonic speed of the moving plasma and associated intensity feature may be most likely evolved in the post flare loop system through impulsive flare heating processes. Complementing our observations of moving multi-temperature intensity features in the post flare loop system and its reflection, we also attempt to solve two-dimensional ideal magnetohydrodynamic equations numerically using the VAL-IIIC atmosphere as an initial condition to simulate the observed plasma dynamics. We consider a localized thermal pulse impulsively generated near one footpoint of the loop system during the flare processes, which is launched along the magnetic field lines at the solar chromosphere. The pulse steepens into a slow shock at higher altitudes while moving along this loop system, which triggers plasma perturbations that closely exhibit the observed plasma dynamics.