New Insights on the Interiors of Coronal Mass Ejections from the WISPR and SoloHI Heliospheric Imagers

Abstract

Much of our current understanding of the internal structure of coronal mass ejections (CMEs) has been based on either high-resolution, multi-wavelength imaging near the Sun or in-situ crossings of a CME, typically near 1 au. Previous remote sensing instruments, observing the corona and heliosphere from close to 1 au, were able to observe CMEs in Thomson scattered white light but were limited in detail that could be resolved by the constraints imposed by observing from such a large distance. As a result, a thorough understanding of the bulk shape and leading-edge propagation in the heliosphere has been developed, but many open questions about the interior of a CME as well as its overall impact on the corona still remain open. Heliospheric Imager data from the Wide Field Imager for Solar Probe (WISPR) on board the Parker Solar Probe and the Solar Orbiter Heliospheric Imager (SoloHI) on board Solar Orbiter have provided new high-resolution imaging by observing from within the inner heliosphere and corona.  The unprecedented resolution of these observations allows us to directly address these key physical questions relating to the internal structure, coherency and evolution of coronal mass ejections as they propagate away from the Sun. Utilizing data from both of these instruments, we will show examples of the complex interior structures present in the images and explain the physical implications of these observations.