Toward a Unified Explanation for the Three-part Structure of Solar Coronal Mass Ejections

TL;DR

This study provides observational evidence supporting a unified explanation for the three-part structure of CMEs, showing that prominences and magnetic flux ropes, whether hot or warm channels, all contribute to the CME core.

Contribution

It demonstrates, for the first time, that coronal cavities can appear as warm channels in EUV, unifying the understanding of CME core origins from prominences and flux ropes.

Findings

Coronal cavities can appear as warm channels in EUV images.

Both prominences and warm-channel flux ropes evolve into CME cores.

Supports a unified model for the three-part CME structure.

Abstract

Coronal mass ejections (CMEs) are associated with the eruption of magnetic flux ropes (MFRs), which usually appear as hot channels in active regions and coronal cavities in quiet-Sun regions. CMEs often exhibit the classical three-part structure in the lower corona when imaged with white-light coronagraphs, including the bright front, dark cavity, and bright core. The bright core and dark cavity have been regarded as the erupted prominence and MFR, respectively, for several decades. However, recent studies clearly demonstrated that both the prominence and hot-channel MFR can be observed as the CME core. The current research presents a three-part CME resulted from the eruption of a coronal prominence cavity on 2010 October 7 with observations from two vantage perspectives, i.e., edge-on from the Earth and face-on from the Solar Terrestrial Relations Observatory (STEREO). Our observations illustrates two important results: (1) For the first time, the erupting coronal cavity is recorded as a channel-like structure in the extreme-ultraviolet passband, analogous to the hot-channel morphology, and is dubbed as warm channel; (2) Both the prominence and warm-channel MFR (coronal cavity) in the extreme-ultraviolet passbands evolve into the CME core in the white-light coronagraphs of STEREO-A. The results support that we are walking toward a unified explanation for the three-part structure of CMEs, in which both prominences and MFRs (hot or warm channels) are responsible for the bright core.