On the Bright Loop Top Emission in Post Eruption Arcades

TL;DR

This paper investigates the origin of bright loop top emissions in post eruption arcades, proposing that they result from collisions of chromospheric evaporation flows, supported by hydrodynamic simulations and spectral line modeling.

Contribution

It introduces a hydrodynamic model explaining brightening formation in PEAs and validates it through spectral line forward modeling matching observations.

Findings

Brightenings caused by collisions of chromospheric evaporation flows.

Hydrodynamic simulations reproduce observed brightening dynamics.

Spectral line intensities match observed flare data.

Abstract

The observations of post eruption arcades (PEAs) in X-rays and EUV reveal strong localised brightenings at the loop top regions. The origin of these brightenings and their dynamics is not well understood to date. Here, we study the dynamics of PEAs using one-dimensional hydrodynamic modelling with the focus on the the understanding of the formation of localised brightening.Our findings suggest that these brightenings are the result of collisions between the counter-streaming chromospheric evaporation from both the foot points. We further perform forward modelling of the emission observed in simulated results in various spectral lines observed by the Extreme-Ultraviolet Imaging Telescope aboard Hinode. The forward modelled intensities in various spectral lines are in close agreement with a flare observed in December 17, 2006 by EIS.