# Coronal cavities: observations and implications for the magnetic environment of prominences

## TL;DR

Coronal cavities are elliptical dark structures that reveal the magnetic flux ropes supporting prominences, with their properties and behaviors providing insights into eruption mechanisms and magnetic configurations.

## Contribution

This paper reviews observational evidence and interprets coronal cavities as magnetic flux ropes, highlighting their role in prominence support and eruption prediction.

## Key findings

- Cavities are elliptical, dark structures indicating magnetic flux ropes.
- Flow patterns and thermal properties relate to eruption precursors.
- Polarization signatures support magnetic flux rope interpretation.

## Abstract

Dark and elliptical, coronal cavities yield important clues to the magnetic structures that cradle prominences, and to the forces that ultimately lead to their eruption. We review observational analyses of cavity morphology, thermal properties (density and temperature), line-of-sight and plane-of-sky flows, substructure including hot cores and central voids, linear polarization signatures, and observational precursors and predictors of eruption. We discuss a magnetohydrodynamic interpretation of these observations which argues that the cavity is a magnetic flux rope, and pose a set of open questions for further study.