{
  "id": "2307.01398",
  "version": "v1",
  "published": "2023-07-03T23:33:18.000Z",
  "updated": "2023-07-03T23:33:18.000Z",
  "title": "The Structure of Coronal Mass Ejections Recorded by the K-Coronagraph at Mauna Loa Solar Observatory",
  "authors": [
    "Hongqiang Song",
    "Leping Li",
    "Zhenjun Zhou",
    "Lidong Xia",
    "Xin Cheng",
    "Yao Chen"
  ],
  "comment": "10 pages, 4 figures, accepted for publication in ApJL",
  "categories": [
    "astro-ph.SR",
    "physics.space-ph"
  ],
  "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 $\\geq$ 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.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2023-07-03T23:33:18.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "mauna loa solar observatory",
      "coronal mass ejections",
      "k-coronagraph",
      "three-part feature",
      "three-part structure"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 10,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}