# Signatures of quiet Sun reconnection events in Ca~{\sc ii}, H$\alpha$ and Fe~{\sc i}

## TL;DR

This study investigates quiet Sun reconnection events through multi-line observations and simulations, revealing that these events resemble Ellerman bombs but occur at higher photospheric layers with magnetic interactions driving their formation.

## Contribution

The paper provides new observational evidence and simulation analysis showing quiet Sun Ellerman bombs form at higher layers and are driven by magnetic field interactions, expanding understanding of solar reconnection phenomena.

## Key findings

- Quiet Sun Ellerman bombs occur at higher photospheric levels.
- Line profiles show asymmetries and timing differences between Ca II and Hα.
- Simulations indicate heating occurs approximately 430 km above the photosphere.

## Abstract

We use observations of quiet Sun (QS) regions in the H$\alpha$ 6563 \AA, Ca~{\sc ii} 8542 \AA\, and Fe~{\sc i} 6302 \AA\ lines. We observe brightenings in the wings of the H$\alpha$ and Ca~{\sc ii} combined with observations of the interacting magnetic concentrations observed in the Stokes signals of Fe~{\sc i}. These brightenings are similar to Ellerman bombs (EBs), i.e. impulsive bursts in the wings of the Balmer lines which leave the line cores unaffected. Such enhancements suggest that these events have similar formation mechanisms to the classical EBs found in active regions, with the reduced intensity enhancements found in the QS regions due to a weaker feeding magnetic flux. The observations also show that the quiet Sun Ellerman bombs (QSEBs) are formed at a higher height in the upper photosphere than the photospheric continuum level. Using simulations, we investigate the formation mechanism associated with the events and suggest that these events are driven by the interaction of magnetic field-lines in the upper photospheric regions. The results of the simulation are in agreement with observations when comparing the light-curves, and in most cases we found that the peak in the Ca~{\sc ii} 8542 \AA\ wing occurred before the peak in H$\alpha$ wing. Moreover, in some cases, the line profiles observed in Ca~{\sc ii} are asymmetrical with a raised core profile. The source of heating in these events is shown by the MURaM simulations and is suggested to occur 430 km above the photosphere.