Unraveling the Trigger Mechanism of Explosive Reconnection in Partially Ionized Solar Plasma

Fuente: arXiv
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Auteurs principaux: Zafar, Abdullah, Ni, Lei, Lin, Jun, Ali, Ahmad
Format: Preprint
Publié: 2024
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author Zafar, Abdullah
Ni, Lei
Lin, Jun
Ali, Ahmad
author_facet Zafar, Abdullah
Ni, Lei
Lin, Jun
Ali, Ahmad
contents Plasmoid instability is usually accounted for the onset of fast reconnection events observed in astrophysical plasmas. However, the measured reconnection rate from observations can be one order of magnitude higher than that derived from MHD simulations. In this study, we present the results of magnetic reconnection in the partially ionized low solar atmosphere based on 2.5D magnetohydrodynamics (MHD) simulations. The whole reconnection process covers two different fast reconnection phases. In the first phase, the slow Sweet-Parker reconnection transits to the plasmoid-mediated reconnection, and the reconnection rate reaches about 0.02. In the second phase, a faster explosive reconnection appears, with the reconnection rate reaching above 0.06. At the same time, a sharp decrease in plasma temperature and density at the principle X-point is observed which is associated with the strong radiative cooling, the ejection of hot plasma from the local reconnection region or the motion of principle X-point from hot and denser region to cool and less dense one along the narrow current sheet. This causes gas pressure depletion and the increasing of magnetic diffusion at the main X-point, resulting in the local Petschek-like reconnection and a violent and rapid increase in the reconnection rate. This study for the first time reveals a common phenomenon that the plasmoid dominated reconnection transits to an explosive faster reconnection with the rate approaching the order of 0.1 in partially ionized plasma in the MHD scale.
format Preprint
id arxiv_https___arxiv_org_abs_2407_01915
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Unraveling the Trigger Mechanism of Explosive Reconnection in Partially Ionized Solar Plasma
Zafar, Abdullah
Ni, Lei
Lin, Jun
Ali, Ahmad
Solar and Stellar Astrophysics
Plasma Physics
Space Physics
Plasmoid instability is usually accounted for the onset of fast reconnection events observed in astrophysical plasmas. However, the measured reconnection rate from observations can be one order of magnitude higher than that derived from MHD simulations. In this study, we present the results of magnetic reconnection in the partially ionized low solar atmosphere based on 2.5D magnetohydrodynamics (MHD) simulations. The whole reconnection process covers two different fast reconnection phases. In the first phase, the slow Sweet-Parker reconnection transits to the plasmoid-mediated reconnection, and the reconnection rate reaches about 0.02. In the second phase, a faster explosive reconnection appears, with the reconnection rate reaching above 0.06. At the same time, a sharp decrease in plasma temperature and density at the principle X-point is observed which is associated with the strong radiative cooling, the ejection of hot plasma from the local reconnection region or the motion of principle X-point from hot and denser region to cool and less dense one along the narrow current sheet. This causes gas pressure depletion and the increasing of magnetic diffusion at the main X-point, resulting in the local Petschek-like reconnection and a violent and rapid increase in the reconnection rate. This study for the first time reveals a common phenomenon that the plasmoid dominated reconnection transits to an explosive faster reconnection with the rate approaching the order of 0.1 in partially ionized plasma in the MHD scale.
title Unraveling the Trigger Mechanism of Explosive Reconnection in Partially Ionized Solar Plasma
topic Solar and Stellar Astrophysics
Plasma Physics
Space Physics
url https://arxiv.org/abs/2407.01915