Petschek-type reconnection in the high-Lundquist-number regime during nonlinear evolution on the tilt instability
May 8, 2020Citations per year
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Abstract: (arXiv)
The process of fast magnetic reconnection supported by the formation of plasmoid chains in the high Lundquist number () regime is investigated using a recently developed adaptive finite-element magnetohydrodynamic (MHD) code. We employ a two-dimensional incompressible model with a set of reduced visco-resistive MHD equations. The tilt instability setup is chosen to provide a three-step mechanism, where two curved current sheets initially form on an Alfv\'enic time scale followed by a second phase of super-Alfv\'enic growth of plasmoid chains for (Baty 2020). A third phase is reached where an ensuing stochastic time-dependent reconnection regime with a fast time-averaged rate independent of is obtained. We reveal the multi-scale current structures during magnetic reconnection, where merging events of plasmoids give rise to monster plasmoids with shocks bounding the outflow regions. At high enough values (typically for ), a dynamical Petschek-type reconnection is achieved with pairs of slow-mode shocks emanating from a small central region containing a few plasmoids. Finally, we briefly discuss the relevance of our results to explain the flaring activity in solar corona and internal disruptions in tokamaks.Note:
- arXiv admin note: text overlap with arXiv:2003.08660, arXiv:2001.07036
- magnetic reconnection -magnetohydrodynamics -plasmas -stars: coronae -Sun: flares
- dimension: 2
- stability
- time dependence
- finite element
- central region
- stochastic
- nonlinear
- formation
- structure
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