The Unresolved Fine Structure Resolved - IRIS observations of the Solar Transition Region

TL;DR

IRIS observations of the solar transition region reveal short, dynamic loops that help resolve longstanding questions about solar atmospheric heating and structure.

Contribution

This study provides high-resolution IRIS observations of low-lying, rapidly evolving loops in the transition region, offering new insights into solar atmospheric heating mechanisms.

Findings

Detection of numerous short, low-lying loops at transition-region temperatures.

Rapid variability of these loops on timescales of minutes.

Implications for solving the coronal heating problem.

Abstract

The heating of the outer solar atmospheric layers, i.e., the transition region and corona, to high temperatures is a long standing problem in solar (and stellar) physics. Solutions have been hampered by an incomplete understanding of the magnetically controlled structure of these regions. The high spatial and temporal resolution observations with the Interface Region Imaging Spectrograph (IRIS) at the solar limb reveal a plethora of short, low lying loops or loop segments at transition-region temperatures that vary rapidly, on the timescales of minutes. We argue that the existence of these loops solves a long standing observational mystery. At the same time, based on comparison with numerical models, this detection sheds light on a critical piece of the coronal heating puzzle.