A Tale of Two Emergences: Sunrise II Observations of Emergence Sites in a Solar Active Region

TL;DR

This paper presents detailed observations of a small-scale magnetic flux emergence event in a solar active region, revealing the dynamic interactions between magnetic fields and plasma during emergence.

Contribution

It provides high-resolution, multi-instrument observations of the emergence process, illustrating the interaction of magnetic fields with solar plasma and the role of reconnection in active region formation.

Findings

Magnetic flux patches push through the photosphere, dragging plasma along.

Downflow channels form at the footpoints of emerging flux.

Magnetic reconnection releases energy, heating the chromosphere.

Abstract

In June 2013, the two scientific instruments onboard the second Sunrise mission witnessed, in detail, a small-scale magnetic flux emergence event as part of the birth of an active region. The Imaging Magnetograph Experiment (IMaX) recorded two small (~5 arcsec) emerging flux patches in the polarized filtergrams of a photospheric Fe I spectral line. Meanwhile, the Sunrise Filter Imager (SuFI) captured the highly dynamic chromospheric response to the magnetic fields pushing their way through the lower solar atmosphere. The serendipitous capture of this event offers a closer look at the inner workings of active region emergence sites. In particular, it reveals in meticulous detail how the rising magnetic fields interact with the granulation as they push through the Sun's surface, dragging photospheric plasma in their upward travel. The plasma that is burdening the rising field slides along the field lines, creating fast downflowing channels at the footpoints. The weight of this material anchors this field to the surface at semi-regular spatial intervals, shaping it in an undulatory fashion. Finally, magnetic reconnection enables the field to release itself from its photospheric anchors, allowing it to continue its voyage up to higher layers. This process releases energy that lights up the arch-filament systems and heats the surrounding chromosphere.