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Title: Magnetic reconnection in the low solar chromosphere with a more realistic radiative cooling model

Journal Article · · Physics of Plasmas
DOI: https://doi.org/10.1063/1.5018351 · OSTI ID:1514857
ORCiD logo [1];  [2]; ORCiD logo [3];  [1]
  1. Chinese Academy of Sciences (CAS), Kunming, Yunnan (China). Yunnan Observatories; Chinese Academy of Sciences (CAS), Beijing (China). Center for Astronomical Mega-Science
  2. National Science Foundation (NSF), Alexandria, VA (United States)
  3. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

Magnetic reconnection is the most likely mechanism responsible for the high temperature events that are observed in strongly magnetized locations around the temperature minimum in the low solar chromosphere. This work improves upon our previous work [Ni et al., Astrophys. J. 852, 95 (2018)] by using a more realistic radiative cooling model computed from the OPACITY project and the CHIANTI database. We find that the rate of ionization of the neutral component of the plasma is still faster than recombination within the current sheet region. For low β plasmas, the ionized and neutral fluid flows are well-coupled throughout the reconnection region resembling the single-fluid Sweet-Parker model dynamics. Decoupling of the ion and neutral inflows appears in the higher β case with β0=1.46, which leads to a reconnection rate about three times faster than the rate predicted by the Sweet-Parker model. In all cases, the plasma temperature increases with time inside the current sheet, and the maximum value is above 2×104 K when the reconnection magnetic field strength is greater than 500 G. While the more realistic radiative cooling model does not result in qualitative changes of the characteristics of magnetic reconnection, it is necessary for studying the variations of the plasma temperature and ionization fraction inside current sheets in strongly magnetized regions of the low solar atmosphere. It is also important for studying energy conversion during the magnetic reconnection process when the hydrogen-dominated plasma approaches full ionization.

Research Organization:
Smithsonian Inst. Cambridge, MA (United States)
Sponsoring Organization:
USDOE Office of Science (SC); National Science Foundation (NSF)
Grant/Contract Number:
SC0016363; AGS-1358342
OSTI ID:
1514857
Journal Information:
Physics of Plasmas, Vol. 25, Issue 4; ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 16 works
Citation information provided by
Web of Science

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Cited By (4)

Plasmoid-mediated reconnection in solar UV bursts journal July 2019
Effect of Ionization and Recombination on the Evolution of the Harris-type Current Sheet in Partially Ionized Plasmas journal October 2019
Transition Region Loops in the Very Late Phase of Flux Emergence in IRIS Sit-and-stare Observations journal December 2019
Transition region loops in the very late phase of flux-emergence in IRIS sit-and-stare observations text January 2019

Figures / Tables (7)