Solar Atmospheric Heating Due to Small-scale Events in an Emerging Flux Region

TL;DR

This study combines high-resolution solar observations and data-driven modeling to analyze small-scale heating events in an emerging flux region, revealing magnetic reconnection as a key heating mechanism affecting both the lower atmosphere and corona.

Contribution

It introduces a comprehensive approach using multi-line spectral inversions and 3D magnetic field simulations to understand small-scale solar atmospheric heating events.

Findings

Small-scale heating events are concentrated at polarity inversion lines.

These events heat both the lower atmosphere and the corona.

Magnetic reconnection is identified as the primary heating mechanism.

Abstract

We investigate the thermal, kinematic and magnetic structure of small-scale heating events in an emerging flux region (EFR). We use high-resolution multi-line observations (including Ca II 8542~\AA, Ca II K, and Fe I 6301~\AA line pair) of an EFR located close to the disk center from the CRISP and CHROMIS instruments at the Swedish 1-m Solar Telescope. We perform non-LTE inversions of multiple spectral lines to infer the temperature, velocity, and magnetic field structure of the heating events. Additionally, we use the data-driven Coronal Global Evolutionary Model to simulate the evolution of the 3D magnetic field configuration above the events and understand their dynamics. Furthermore, we analyze the differential emission measure to gain insights into the heating of the coronal plasma in the EFR. Our analysis reveals the presence of numerous small-scale heating events in the EFR, primarily located at polarity inversion lines of bipolar structures. These events not only heat the lower atmosphere but also significantly heat the corona. The data-driven simulations, along with the observed enhancement of currents and Poynting flux, suggest that magnetic reconnection in the lower atmosphere is likely responsible for the observed heating at these sites.