New Observations Needed to Advance Our Understanding of Coronal Mass Ejections

TL;DR

This paper emphasizes the need for enhanced observational data and new missions to better understand the complex 3D structure and evolution of coronal mass ejections from the Sun.

Contribution

It identifies key data sets and observational priorities to improve understanding of CMEs' structure and evolution, proposing future missions and instruments.

Findings

Current measurements are insufficient for 3D CME analysis

Prioritized data sets can significantly improve CME understanding

Proposed missions could yield substantial advancements

Abstract

Coronal mass ejections (CMEs) are large eruptions from the Sun that propagate through the heliosphere after launch. Observational studies of these transient phenomena are usually based on 2D images of the Sun, corona, and heliosphere (remote-sensing data), as well as magnetic field, plasma, and particle samples along a 1D spacecraft trajectory (in-situ data). Given the large scales involved and the 3D nature of CMEs, such measurements are generally insufficient to build a comprehensive picture, especially in terms of local variations and overall geometry of the whole structure. This White Paper aims to address this issue by identifying the data sets and observational priorities that are needed to effectively advance our current understanding of the structure and evolution of CMEs, in both the remote-sensing and in-situ regimes. It also provides an outlook of possible missions and instruments that may yield significant improvements into the subject.