Signatures of ubiquitous magnetic reconnection in the lower solar atmosphere

TL;DR

This study reveals that small-scale magnetic reconnection events, called QSEBs, are widespread in the quiet Sun's lower atmosphere, significantly more numerous than previously observed, and likely contribute to chromospheric energy balance.

Contribution

First high-resolution observations of QSEBs in Hβ line showing their ubiquity and higher occurrence rate, indicating frequent magnetic reconnection in the solar lower atmosphere.

Findings

QSEBs are ubiquitously distributed in the quiet Sun.

The occurrence of QSEBs is over ten times higher than in earlier Hα observations.

QSEB brightenings persist in line core with delays and offsets, indicating vertical extension of reconnection sites.

Abstract

Ellerman Bomb-like brightenings of the hydrogen Balmer line wings in the quiet Sun (QSEBs) are a signature of the fundamental process of magnetic reconnection at the smallest observable scale in the solar lower atmosphere. We analyze high spatial resolution observations (0.1 arcsec) obtained with the Swedish 1-m Solar Telescope to explore signatures of QSEBs in the H$\beta$ line. We find that QSEBs are ubiquitous and uniformly distributed throughout the quiet Sun, predominantly occurring in intergranular lanes. We find up to 120 QSEBs in the FOV for a single moment in time; this is more than an order of magnitude higher than the number of QSEBs found in earlier H$\alpha$ observations. This suggests that about half a million QSEBs could be present in the lower solar atmosphere at any given time. The QSEB brightening found in the H$\beta$ line wings also persist in the line core with a temporal delay and spatial offset towards the nearest solar limb. Our results suggest that QSEBs emanate through magnetic reconnection along vertically extended current sheets in the solar lower atmosphere. The apparent omnipresence of small-scale magnetic reconnection may play an important role in the energy balance of the solar chromosphere.