Global impact of emerging internetwork fields on the low solar atmosphere

TL;DR

This study investigates the influence of emerging internetwork magnetic fields on the solar atmosphere, finding that only large bipoles significantly heat the low solar atmosphere, with the overall impact being marginal.

Contribution

It provides the first comprehensive analysis of the global impact of internetwork magnetic fields on the quiet Sun's energetics using high-resolution multi-wavelength observations.

Findings

Large IN bipoles can locally heat the solar atmosphere.

The global contribution of IN bipoles is likely marginal.

Detection limitations affect the assessment of smaller IN fields.

Abstract

Small-scale, newly emerging internetwork (IN) magnetic fields are considered a viable source of energy and mass for the solar chromosphere and possibly the corona. Multiple studies show that single events of flux emergence can indeed locally heat the low solar atmosphere through interactions of the upward propagating magnetic loops and the preexisting ambient field lines. However, the global impact of the newly emerging IN fields on the solar atmosphere is still unknown. In this paper, we study the spatio-temporal evolution of IN bipolar flux features and analyze their impact on the energetics and dynamics of the quiet Sun atmosphere. We use high resolution, multi-wavelength, coordinated observations obtained with the Interface Region Imaging Spectrograph (IRIS), Hinode, and the Solar Dynamics Observatory (SDO) to identify emerging IN magnetic fields and follow their evolution. Our observational results suggest that only the largest IN bipoles are capable of heating locally the low solar atmosphere, while the global contribution of these bipoles appears to be marginal. However, the total number of bipoles detected and their impact estimated in this work is limited by the sensitivity level, spatial resolution, and duration of our observations. To detect smaller and weaker IN fields that would maintain the basal flux, and examine their contribution to the chromospheric heating, we will need higher resolution, higher sensitivity and longer time series obtained with current and next-generation ground- and space-based telescopes.