Fleeting Small-scale Surface Magnetic Fields Build the Quiet-Sun Corona

TL;DR

This study shows that small, fleeting magnetic fields on the solar surface are fundamental in forming and energizing the quiet-Sun corona, revealing a highly dynamic magnetic environment.

Contribution

It demonstrates that transient, small-scale magnetic fields are key to understanding the origin and heating of quiet-Sun coronal loops, based on high-resolution Solar Orbiter data.

Findings

Coronal loops connect to regions with fleeting, mixed-polarity magnetic patches.

Magnetic fields with fluxes as low as 10^{15} Mx influence coronal structuring.

Coronal disturbances can originate from small, rapidly evolving magnetic areas.

Abstract

Arch-like loop structures filled with million Kelvin hot plasma form the building blocks of the quiet-Sun corona. Both high-resolution observations and magnetoconvection simulations show the ubiquitous presence of magnetic fields on the solar surface on small spatial scales of $\sim$100\,km. However, the question of how exactly these quiet-Sun coronal loops originate from the photosphere and how the magnetic energy from the surface is channeled to heat the overlying atmosphere is a long-standing puzzle. Here we report high-resolution photospheric magnetic field and coronal data acquired during the second science perihelion of Solar Orbiter that reveal a highly dynamic magnetic landscape underlying the observed quiet-Sun corona. We found that coronal loops often connect to surface regions that harbor fleeting weaker, mixed-polarity magnetic field patches structured on small spatial scales, and that coronal disturbances could emerge from these areas. We suggest that weaker magnetic fields with fluxes as low as $10^{15}$\,Mx and/or those that evolve on timescales less than 5\,minutes, are crucial to understand the coronal structuring and dynamics.