Advancement in CME Research and the Need for Multipoint Measurements

Coronal mass ejections (CMEs) are dynamic and rapidly evolving large solar eruptions. Over the past few decades they have been studied through remote observations using imagers from one to three spacecraft, direct measurements using single-spacecraft in situ measurements, or, in random and relatively rare conjunctions, the combination of multiple instruments. In spite of multiple missions that have provided observations of CMEs, there hasn't been a dedicated multi-point mission to study them. The work by Burlaga et al (1981), the foundation of all work on magnetic cloud for the past 40 years, was based on a rare conjunction of five spacecraft observing the same event. No such conjunction has been reported to have taken place since then. In order to better understand the structure and evolution of CMEs, a cluster of spacecraft is needed to provide systematic multi-point measurements of CMEs. In this work, we discuss the advancements in CME research using coincidental multi-point measurements and numerical simulations and propose the path forward which will require dedicated missions.