2D cellular automaton model for the evolution of active region coronal plasmas

Abstract

We study a 2D cellular automaton (CA) model for the evolution of coronal loop plasmas. The model is based on the idea that coronal loops are made of elementary magnetic strands that are tangled and stressed by the displacement of their footpoints by photospheric motions. The magnetic stress accumulated between neighbor strands is released in sudden reconnection events or nanoflares that heat the plasma. We combine the CA model with the Enthalpy Based Thermal Evolution of Loops (EBTEL) model to compute the response of the plasma to the heating events. Using the known response of the XRT telescope on board Hinode we also obtain synthetic data. The model obeys easy to understand scaling laws relating the output (nanoflare energy, temperature, density, intensity) to the input parameters (field strength, strand length, critical misalignment angle). The nanoflares have a power-law distribution with a universal slope of -2.5, independent of the input parameters. The repetition frequency of nanoflares, expressed in terms of the plasma cooling time, increases with strand length. We discuss the implications of our results for the problem of heating and evolution of active region coronal plasmas.

arXiv commentPaper 1 of 2: Model description. \bibitem[L{ó}pez Fuentes \& Klimchuk(2015)]{2015ApJ...799..128L} L{ó}pez Fuentes, M., \& Klimchuk, J.~A.\ 2015, \apj, 799, 128

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• Patterns of Activity in a Global Model of a Solar Active Region
• Power-Law Statistics Of Driven Reconnection In The Magnetically Closed Corona
• A nanoflare based cellular automaton model and the observed properties of the coronal plasma
• EUV flickering of solar coronal loops: a new diagnostic of coronal heating
• Transition region contribution to AIA observations in the context of coronal heating
• Modeling of Condensations in Coronal Loops Produced by Impulsive Heating
• Nanoflare Diagnostics from Magnetohydrodynamic Heating Profiles
• Three-Dimensional Reconstruction and Thermal Modelling of Observed Loops