Analysis and Modeling of Two Flare Loops Observed by AIA and EIS

TL;DR

This study models the heating and evolution of two flare loops observed by AIA and EIS, using empirical heating functions and the EBTEL model, to understand their plasma dynamics during a solar flare.

Contribution

It introduces a method to infer empirical heating functions from UV light curves and applies the EBTEL model to simulate plasma evolution in flare loops.

Findings

Synthetic EUV light curves agree with observations within a factor of two.

Different loop lengths and heating functions lead to distinct plasma evolution patterns.

Computed velocities match Doppler shift measurements during decay phase.

Abstract

We analyze and model an M1.0 flare observed by SDO/AIA and Hinode/EIS to investigate how flare loops are heated and evolve subsequently. The flare is composed of two distinctive loop systems observed in EUV images. The UV 1600 \AA emission at the feet of these loops exhibits a rapid rise, followed by enhanced emission in different EUV channels observed by AIA and EIS. Such behavior is indicative of impulsive energy deposit and the subsequent response in overlying coronal loops that evolve through different temperatures. Using the method we recently developed, we infer empirical heating functions from the rapid rise of the UV light curves for the two loop systems, respectively, treating them as two big loops of cross-sectional area 5\arcsec by 5\arcsec, and compute the plasma evolution in the loops using the EBTEL model (Klimchuk et al. 2008). We compute the synthetic EUV light curves, which, with the limitation of the model, reasonably agree with observed light curves obtained in multiple AIA channels and EIS lines: they show the same evolution trend and their magnitudes are comparable by within a factor of two. Furthermore, we also compare the computed mean enthalpy flow velocity with the Doppler shift measurements by EIS during the decay phase of the two loops. Our results suggest that the two different loops with different heating functions as inferred from their footpoint UV emission, combined with their different lengths as measured from imaging observations, give rise to different coronal plasma evolution patterns captured both in the model and observations.