Small EUV Brightenings in the Quiet Solar Atmosphere: New Insights from the Solar Orbiter Mission

TL;DR

The Solar Orbiter mission has uncovered ubiquitous, small-scale, impulsive EUV brightenings in the quiet Sun, revealing insights into energy transfer processes and their potential role in heating the solar corona.

Contribution

This paper presents new high-resolution observations and simulations of small-scale EUV events, demonstrating their prevalence and physical similarity across scales.

Findings

Small-scale EUV brightenings are everywhere on the quiet Sun.

These events are highly impulsive and dynamic.

Their properties suggest scale-independent physical processes.

Abstract

One of the many outcomes of the Solar Orbiter mission is the evidence for the solar atmosphere being filled by highly impulsive bursts, down to about 200 km scale: the limit of the EUV instruments' spatial resolution. Small-scale events of this kind were already known, but their observation was occasional or with limited, lower resolution. Solar Orbiter has revealed that small scale, highly impulsive events are everywhere on the quiet Sun, all the time, at even smaller scales. Their similarity with known larger features, are the witnesses that the physical processes causing them are independent of the spatial scales involved. Their highly dynamic property is the signature of energy transfer and/or local dissipation. Their investigation can thus elucidate on the dominant physical processes acting on the solar atmosphere and on the possible role in the origin of the hot solar corona. In this review, we will present a summary of the observational and simulation results on this topic, led by the results from data taken by the Extreme Ultraviolet Imager (EUI)/High Resolution Imagers (HRIEUV) instrument. Here, we will cover both statistical properties and analyses of individual events.