A Cancellation Nanoflare Model for Solar Chromospheric and Coronal Heating II. 2D Theory and Simulations

Abstract

Recent observations at high spatial resolution have shown that magnetic flux cancellation occurs on the solar surface much more frequently than previously thought, and so this led Priest et al 2018 to propose magnetic reconnection driven by photospheric flux cancellation as a mechanism for chromospheric and coronal heating. In particular, they estimated analytically the amount of energy released as heat and the height of the energy release during flux cancellation. In the present work, we take the next step in the theory by setting up a two-dimensional resistive MHD simulation of two canceling polarities in the presence of a horizontal external field and a stratified atmosphere in order to check and improve upon the analytical estimates. Computational evaluation of the energy release during reconnection is found to be in good qualitative agreement with the analytical estimates. In addition, we go further and undertake an initial study of the atmospheric response to reconnection. We find that, during the cancellation, either hot ejections or cool ones or a combination of both hot and cool ejections can be formed, depending on the height of the reconnection location. The hot structures can have the density and temperature of coronal loops, while the cooler structures are suggestive of surges and large spicules.

19 pages, 13 figures

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Cited by in corpus (15)

• Generation of Solar Spicules and Subsequent Atmospheric Heating
• Ellerman bombs and UV bursts: transient events in chromospheric current sheets
• Flame-like Ellerman Bombs and Their Connection to Solar UV Bursts
• A Magnetic Reconnection model for Hot Explosions in the Cool Atmosphere of the Sun
• Signatures of ubiquitous magnetic reconnection in the lower solar atmosphere
• Onset of turbulent fast magnetic reconnection observed in the solar atmosphere
• A 2D Model for Coronal Bright Points: Association with Spicules, UV bursts, Surges and EUV Coronal Jets
• Energetics of magnetic transients in a solar active region plage
• Heating at the remote footpoints as a brake on jet flows along loops in the solar atmosphere
• Chromospheric and coronal heating and jet acceleration due to reconnection driven by flux cancellation. I. At a three-dimensional current sheet
• Coronal Heating and Solar Wind Generation by Flux Cancellation Reconnection
• Further Evidence for Looplike Fine Structure inside "Unipolar" Active Region Plages
• Transient Formation of Loops in the Core of an Active Region
• A comparative study of resistivity models for simulations of magnetic reconnection in the solar atmosphere. II. Plasmoid formation
• An Observational Test of Solar Plasma Heating by Magnetic Flux Cancellation