Evolution of dynamic fibrils from the cooler chromosphere to the hotter corona

TL;DR

This study uses coordinated multi-instrument observations to establish a direct link between chromospheric and coronal dynamic fibrils, revealing their thermal evolution and shock-driven plasma dynamics reaching temperatures of about 1.5 million Kelvin.

Contribution

It provides the first direct observational evidence connecting chromospheric DFs with their coronal counterparts and details their thermal and dynamic evolution through the solar atmosphere.

Findings

DFs observed at different atmospheric layers are closely correlated.

DFs can reach temperatures of approximately 1.5 million Kelvin.

Shock-driven plasma pile-up occurs at the tips of DFs, forming bright blobs in coronal images.

Abstract

Dynamic fibrils (DFs) are commonly observed chromospheric features in solar active regions. Recent observations from the Extreme Ultraviolet Imager (EUI) aboard the Solar Orbiter have revealed unambiguous signatures of DFs at the coronal base, in extreme ultraviolet (EUV) emission. However, it remains unclear if the DFs detected in the EUV are linked to their chromospheric counterparts. Simultaneous detection of DFs from chromospheric to coronal temperatures could provide important information on their thermal structuring and evolution through the solar atmosphere. In this paper, we address this question by using coordinated EUV observations from the Atmospheric Imaging Assembly (AIA), Interface Region Imaging Spectrograph (IRIS), and EUI to establish a one-to-one correspondence between chromospheric and transition region DFs (observed by IRIS) with their coronal counterparts (observed by EUI and AIA). Our analysis confirms a close correspondence between DFs observed at different atmospheric layers, and reveals that DFs can reach temperatures of about 1.5 million Kelvin, typical of the coronal base in active regions. Furthermore, intensity evolution of these DFs, as measured by tracking them over time, reveals a shock-driven scenario in which plasma piles up near the tips of these DFs and, subsequently, these tips appear as bright blobs in coronal images. These findings provide information on the thermal structuring of DFs and their evolution and impact through the solar atmosphere.