The Structure of Coronal Mass Ejections Recorded by the K-Coronagraph at Mauna Loa Solar Observatory

Abstract

Previous survey studies reported that coronal mass ejections (CMEs) can exhibit various structures in white-light coronagraphs, and $\sim$30\% of them have the typical three-part feature in the high corona (e.g., 2--6 $R_{\odot }$), which has been taken as the prototypical structure of CMEs. It is widely accepted that CMEs result from eruption of magnetic flux ropes (MFRs), and the three-part structure can be understood easily by means of the MFR eruption. It is interesting and significant to answer why only $\sim$30\% of CMEs have the three-part feature in previous studies. Here we conduct a synthesis of the CME structure in the field of view (FOV) of K-Coronagraph (1.05--3 $R_{\odot }$). In total, 369 CMEs are observed from 2013 September to 2022 November. After inspecting the CMEs one by one through joint observations of the AIA, K-Coronagraph and LASCO/C2, we find 71 events according to the criteria: 1) limb event; 2) normal CME, i.e., angular width $\ge$ 30${}^{\circ }$; 3) K-Coronagraph caught the early eruption stage. All (or more than 90\% considering several ambiguous events) of the 71 CMEs exhibit the three-part feature in the FOV of K-Coronagraph, while only 30--40\% have the feature in the C2 FOV (2--6 $R_{\odot }$). For the first time, our studies show that 90--100\% and 30--40\% of normal CMEs possess the three-part structure in the low and high corona, respectively, which demonstrates that many CMEs can lose the three-part feature during their early evolutions, and strongly supports that most (if not all) CMEs have the MFR structures.

10 pages, 4 figures, accepted for publication in ApJL

References in corpus (14)

• Observation of An Evolving Magnetic Flux Rope Prior To and During A Solar Eruption
• A fundamental mechanism of solar eruption initiation
• The Depiction of Coronal Structure in White Light Images
• Direct observations of magnetic flux rope formation during a solar coronal mass ejection
• The formation of an inverse S-shaped active-region filament driven by sunspot motion and magnetic reconnection
• Non-equilibrium Flux Rope Formation by Confined Flares Preceding a Solar Coronal Mass Ejection
• Toward a Unified Explanation for the Three-part Structure of Solar Coronal Mass Ejections
• The Structure of Solar Coronal Mass Ejections in the Extreme-Ultraviolet Passbands
• On the Nature of the Three-part Structure of Solar Coronal Mass Ejections
• Do All Interplanetary Coronal Mass Ejections Have A Magnetic Flux Rope Structure Near 1 AU?
• First Taste of Hot Channel in Interplanetary Space
• Rapid Rotation of an Erupting Prominence and the Associated Coronal Mass Ejection on 13 May 2013
• Overexpansion-dominated Coronal Mass Ejection Formation and Induced Radio Bursts
• Quantification of the Writhe Number Evolution of Solar Filament Axes

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