Spontaneous non-steady magnetic reconnection within the solar environment

Abstract

This work presents a 2.5-dimensional simulation study of the instability of current-sheets located in a medium with a strong density variation along the current layer. The initial force-free configuration is observed to undergo a two-stage evolution consisting of an abrupt regime transition from a slow to a fast reconnection process leading the system to a final chaotic configuration. Yet, the onset of the fast phase is not determined by the presence of any anomalous enhancement in plasma's local resistivity, but rather is the result of a new mechanism discovered in Lapenta (2008)* and captured only when sufficient resolution is present. Hence, the effects of the global resistivity, the global viscosity and the plasma beta on the overall dynamics are considered. This mechanism allowing the transition from slow to fast reconnection provides a simple but effective model of several processes taking place within the solar atmosphere from the high chromosphere up to the low corona. In fact, the understanding of a spontaneous transition to a self-feeding fast reconnection regime as well as its macroscopic evolution is the first and fundamental step to produce realistic models of all those phenomena requiring fast (and high power) triggering events (* Lapenta G. 2008, Phys. Rev. Lett., 100, 235001).

29 pages, 10 figures

References in corpus (6)

• Instability of current sheets and formation of plasmoid chains
• Chromospheric Anemone Jets as Evidence of Ubiquitous Reconnection
• Numerical Tests of Fast Reconnection in Weakly Stochastic Magnetic Fields
• Self-Feeding Turbulent Magnetic Reconnection on Macroscopic Scales
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Cited by in corpus (7)

• Turbulence, Magnetic Reconnection in Turbulent Fluids and Energetic Particle Acceleration
• Plasmoid and Kelvin-Helmholtz instabilities in Sweet-Parker current sheets
• Relation of Astrophysical Turbulence and Magnetic Reconnection
• Fast Magnetic Reconnection and Energetic Particle Acceleration
• Achieving Fast Reconnection in Resistive MHD Models via Turbulent Means
• Spontaneous transition to a fast 3D turbulent reconnection regime
• On magnetic reconnection as promising driver for future plasma propulsion systems