RADYN simulations of non-thermal and thermal models of Ellerman bombs

TL;DR

This study uses radiative hydrodynamic simulations to compare non-thermal and thermal models of Ellerman bombs, revealing distinct spectral signatures that can help identify the dominant heating mechanism.

Contribution

It introduces detailed simulations of EBs with both heating models, highlighting differences in spectral line profiles and their implications for understanding EB heating processes.

Findings

Non-thermal models show dimming in Hα wings and continuum during heating.

Thermal models exhibit dimming only in Hα core with longer duration.

Higher heating rates produce unrealistically strong Hα lines without UV signatures.

Abstract

Ellerman bombs (EBs) are brightenings in the H$\alpha$ line wings that are believed to be caused by magnetic reconnection in the lower atmosphere. To study the response and evolution of the chromospheric line profiles, we perform radiative hydrodynamic simulations of EBs using both non-thermal and thermal models. Overall, these models can generate line profiles that are similar to observations. However, in non-thermal models we find dimming in the H$\alpha$ line wings and continuum when the heating begins, while for the thermal models dimming occurs only in the H$\alpha$ line core, and with a longer lifetime. This difference in line profiles can be used to determine whether an EB is dominated by non-thermal heating or thermal heating. In our simulations, if a higher heating rate is applied, the H$\alpha$ line will be unrealistically strong, while there are still no clear UV burst signatures.