Radio Imaging Spectropolarimetry of CMEs and CME Progenitors

TL;DR

This paper discusses how advanced radio imaging spectropolarimetry can significantly improve understanding of coronal mass ejections (CMEs) and their magnetic structures, emphasizing the need for dedicated solar radio facilities.

Contribution

It highlights the potential of broadband radio imaging spectropolarimetry with high dynamic range and fidelity, supported by synthetic models, for studying CMEs and their progenitors.

Findings

Synthetic observations demonstrate the diagnostic potential.

Radio diagnostics can constrain magnetic fields and energetic electrons.

A dedicated solar radio facility is recommended.

Abstract

Coronal mass ejections (CMEs) are the most important drivers of space weather. Central to most CMEs is thought to be the eruption of a bundle of highly twisted magnetic field lines known as magnetic flux ropes. A comprehensive understanding of CMEs and their impacts hence requires detailed observations of physical parameters that lead to the formation, destabilization, and eventual eruption of the magnetic flux ropes. Recent advances in remote-sensing observations of coronal cavities, filament channels, sigmoids, EUV "hot channels," white light CMEs, and in situ observations of magnetic clouds points to the possibility of significant progress in understanding CMEs. In this white paper, we provide a brief overview of the potential of radio diagnostics for CMEs and CME progenitors, with a particular focus on the unique means for constraining their magnetic field and energetic electron population. Using synthetic observations based on realistic 3D MHD models, we also demonstrate the transformative potential of advancing such diagnostics by using broadband radio imaging spectropolarimetry with a high image dynamic range and high image fidelity. To achieve this goal, a solar-dedicated radio facility with such capabilities is recommended for implementation in the coming decade.