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Title: Tracking the evolution of a coherent magnetic flux rope continuously from the inner to the outer corona

The magnetic flux rope (MFR) is believed to be the underlying magnetic structure of coronal mass ejections (CMEs). However, it remains unclear how an MFR evolves into and forms the multi-component structure of a CME. In this paper, we perform a comprehensive study of an extreme-ultraviolet (EUV) MFR eruption on 2013 May 22 by tracking its morphological evolution, studying its kinematics, and quantifying its thermal property. As EUV brightenings begin, the MFR starts to rise slowly and shows helical threads winding around an axis. Meanwhile, cool filamentary materials descend spirally down to the chromosphere. These features provide direct observational evidence of intrinsically helical structure of the MFR. Through detailed kinematical analysis, we find that the MFR evolution has two distinct phases: a slow rise phase and an impulsive acceleration phase. We attribute the first phase to the magnetic reconnection within the quasi-separatrix layers surrounding the MFR, and the much more energetic second phase to the fast magnetic reconnection underneath the MFR. We suggest that the transition between these two phases is caused by the torus instability. Moreover, we identify that the MFR evolves smoothly into the outer corona and appears as a coherent structure within the white-light CME volume. Themore » MFR in the outer corona was enveloped by bright fronts that originated from plasma pile-up in front of the expanding MFR. The fronts are also associated with the preceding sheath region followed by the outmost MFR-driven shock.« less
Authors:
; ; ; ; ;  [1] ;  [2] ;  [3] ;  [4]
  1. School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China)
  2. Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)
  3. State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing (China)
  4. Department of Physics, Institute for Astrophysics and Computational Sciences, The Catholic University of America, Washington, DC 20064 (United States)
Publication Date:
OSTI Identifier:
22348363
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 780; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; CHROMOSPHERE; ERUPTION; EVOLUTION; EXTREME ULTRAVIOLET RADIATION; INSTABILITY; LAYERS; MAGNETIC FIELDS; MAGNETIC FLUX; MAGNETIC RECONNECTION; MASS; PLASMA; SUN; THERMODYNAMIC PROPERTIES; VISIBLE RADIATION