Magnetic reconnection in strongly magnetized regions of the low solar chromosphere

Abstract

Magnetic reconnection in strongly magnetized regions around the temperature minimum region of the low solar atmosphere is studied by employing MHD-based simulations of a partially ionized plasma within a reactive 2.5D multi-fluid model. It is shown that in the absence of magnetic nulls in a low $\beta$ plasma the ionized and neutral fluid flows are well-coupled throughout the reconnection region. However, non-equilibrium ionization-recombination dynamics play a critical role in determining the structure of the reconnection region, lead to much lower temperature increases and a faster magnetic reconnection rate as compared to simulations that assume plasma to be in ionization-recombination equilibrium. The rate of ionization of the neutral component of the plasma is always faster than recombination within the current sheet region even when the initial plasma $\beta$ is as high as ${\beta }_0=1.46$. When the reconnecting magnetic field is in excess of a kilogauss and the plasma $\beta$ is lower than 0.0145, the initially weakly ionized plasmas can become fully ionized within the reconnection region and the current sheet can be strongly heated to above $2.5\times 10^4$~K, even as most of the collisionally dissipated magnetic energy is radiated away. The Hall effect increases the reconnection rate slightly, but in the absence of magnetic nulls it does not result in significant asymmetries or change the characteristics of the reconnection current sheet down to meter scales.

References in corpus (10)

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• General Theory of the Plasmoid Instability
• Plasmoid Instability in Evolving Current Sheets and Onset of Fast Reconnection
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• Heating mechanisms in the low solar atmosphere through magnetic reconnection in current sheets
• Spectral observations of Ellerman bombs and fitting with a two-cloud model
• Small-Scale Structuring Of Ellerman Bombs at Solar Limb
• Observational Evidence of Magnetic Reconnection for Brightenings and Transition Region Arcades in IRIS observations
• Asymmetric Magnetic Reconnection in Weakly Ionized Chromospheric Plasmas

Cited by in corpus (13)

• Magnetic reconnection in the era of exascale computing and multiscale experiments
• Ellerman bombs and UV bursts: transient events in chromospheric current sheets
• Flame-like Ellerman Bombs and Their Connection to Solar UV Bursts
• Dissecting bombs and bursts: non-LTE inversions of low-atmosphere reconnection in SST and IRIS observations
• A Magnetic Reconnection model for Hot Explosions in the Cool Atmosphere of the Sun
• Coalescence Instability in Chromospheric Partially Ionised Plasmas
• Magnetic field amplification and structure formation by the Rayleigh-Taylor instability
• Plausibility of ultraviolet burst generation in the low solar chromosphere
• Collisional ionisation and recombination effects on coalescence instability in chromospheric partially ionised plasmas
• Transition region loops in the very late phase of flux-emergence in IRIS sit-and-stare observations
• The Ellerman bomb and Ultraviolet burst triggered successively by an emerging magnetic flux rope
• Two-dimensional modeling of the tearing-mode-governed magnetic reconnection in the large-scale current sheet above the two-ribbon flare
• Observations of the formation of a proto-spot in a pre-existing field environment