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Dynamical and Physical Properties of a Post-Coronal Mass Ejection Current SheetIn the eruptive process of the Kopp-Pneuman type, the closed magnetic field is stretched by the eruption so much that it is usually believed to be " open " to infinity. Formation of the current sheet in such a configuration makes it possible for the energy in the coronal magnetic field to quickly convert into thermal and kinetic energies and cause significant observational consequences, such as growing postflare/CME loop system in the corona, separating bright flare ribbons in the chromosphere, and fast ejections of the plasma and the magnetic flux. An eruption on 2002 January 8 provides us a good opportunity to look into these observational signatures of and place constraints on the theories of eruptions. The event started with the expansion of a magnetic arcade over an active region, developed into a coronal mass ejection (CME), and left some thin streamer-like structures with successively growing loop systems beneath them. The plasma outflow and the highly ionized states of the plasma inside these streamer-like structures, as well as the growing loops beneath them, lead us to conclude that these structures are associated with a magnetic reconnection site, namely, the current sheet, of this eruptive process. We combine the data from the Ultraviolet Coronagraph Spectrometer, Large Angle and Spectrometric Coronagraph Experiment, EUV Imaging Telescope, and Coronal Diagnostic Spectrometer on board the Solar and Heliospheric Observatory, as well is from the Mauna Loa Solar Observatory Mark IV K-coronameter, to investigate the morphological and dynamical properties of this event, as well as the physical properties of the current sheet. The velocity and acceleration of the CME reached up to 1800 km/s and 1 km/sq s, respectively. The acceleration is found to occur mainly at the lower corona (<2.76 Solar Radius). The post-CME loop systems showed behaviors of both postflare loops (upward motion with decreasing speed) and soft X-ray giant arches (upward motion with constant speed, or acceleration) according to the definition of Svestka. In the current sheet, the presence of highly ionized ions, such as Fe(+17) and Ca(+13), suggests temperature as high as (3-4) x 10(exp 6) K, and the plasma outflows have speeds ranging from 300 to 650 km/s. Absolute elemental abundances in the current sheet show a strong first ionization potential effect and have values similar to those found in the active region streamers. The magnetic field strength in the vicinity of the current sheet is found to be of the order of 1 G.
Document ID
20050160223
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Ko, Yuan-Kuen
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Raymond, John C.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Lin, Jun
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Lawrence, Gareth
(Catholic Univ. of America Washington, DC, United States)
Li, Jing
(Hawaii Univ. Honolulu, HI, United States)
Fludra, Andrzej
(Rutherford Appleton Lab. Chilton, United Kingdom)
Date Acquired
August 23, 2013
Publication Date
September 10, 2003
Publication Information
Publication: The AStrophysical Journal
Publisher: Chicago Univ. Press
Volume: 594
Issue: Pt 1
Subject Category
Solar Physics
Funding Number(s)
CONTRACT_GRANT: NAG5-11420
Distribution Limits
Public
Copyright
Public Use Permitted.
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