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

Abstract

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 ["Magnetic Reconnection in Strongly Magnetized Regions of the Low Solar Chromosphere", The Astrophysical Journal 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 $\beta$ 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 $\beta$ case with ${\beta }_0=1.46$, 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 $2\times 10^4$~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.

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Cited by in corpus (12)

• Plasmoid-mediated reconnection in solar UV bursts
• Dissecting bombs and bursts: non-LTE inversions of low-atmosphere reconnection in SST and IRIS observations
• Onset of secondary instabilities and plasma heating during magnetic reconnection in strongly magnetized regions of the low solar atmosphere
• A Magnetic Reconnection model for Hot Explosions in the Cool Atmosphere of the Sun
• Two-fluid simulations of Rayleigh-Taylor instability in a magnetized solar prominence thread II. Effects of collisionality
• Coalescence Instability in Chromospheric Partially Ionised Plasmas
• Magnetic field amplification and structure formation by the Rayleigh-Taylor instability
• 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
• Consistent transport properties in multicomponent two-temperature magnetized plasmas:
• Future Prospects for Partially Ionised Solar Plasmas: the Prominence Case
• Fast magneto-acoustic waves in the solar chromosphere: Comparison of single-fluid and two-fluid approximations