Spectroscopic and imaging observations of small-scale reconnection events

TL;DR

This study uses spectroscopic and imaging data to observe small-scale magnetic reconnection events on the Sun, revealing their multi-layered nature and potential role in coronal heating.

Contribution

First detection of magnetic reconnection processes spanning from the photosphere to the corona using IRIS and AIA observations.

Findings

IRIS jets exhibit bi-directional velocities and non-Gaussian line profiles.

Magnetic flux cancellation coincides with jet activity.

EUV brightening follows IRIS jets, indicating coronal response.

Abstract

We present spectroscopic and imaging observations of small-scale reconnection events on the Sun. Using the Interface Region Imaging Spectrograph (IRIS) observations, one reconnection event is first detected as IRIS jets with fast bi-directional velocities in the chromosphere and transition region, which are identified as non-Gaussian broadenings with two extended wings in the line profiles of Si iv, C ii, and Mg ii k. The magnetograms under the IRIS jets from Helioseismic and Magnetic Images exhibit magnetic flux cancellation simultaneously, supporting that the IRIS jets are driven by magnetic reconnection. The Atmospheric Imaging Assembly images also show an extreme ultraviolet (EUV) brightening which is shortly after the underlying IRIS jets, i.e., in the 131 A, 171 A, 193 A, 211 A, and 94 A channels, implying that the over-lying EUV brightening in the corona is caused by the IRIS jets in the chromosphere and transition region. We also find another three reconnection events which show the same features during this IRIS observation. Our observational results suggest that the small-scale reconnection events might contribute to the coronal heating. The new result is that the process of magnetic reconnection is detected from the photosphere through chromosphere and transition region to the corona.