2010/10/31 by Yi-Min Huang, A. Bhattacharjee, Brian P. Sullivan · 2 citations
Physics and Astronomy · #Current sheet #Hall effect #Instability #Ionosphere and magnetosphere dynamics #Kinetic energy #Magnetic confinement fusion research #Magnetic reconnection #Magnetohydrodynamics #Plasmoid #Solar and Space Plasma Dynamics #astro-ph.SR #physics.flu-dyn #physics.plasm-ph
paper · pdf · doi:10.1063/1.3606363
published as Phys.Plasmas 18:072109,2011 · Accepted for publication in Physics of Plasmas
openalex publication_date 2011/07/01 · arxiv created 2011/07/18 · arxiv updated 2011/07/28 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
The role of a super-Alfvénic plasmoid instability in the onset of fast reconnection is studied by means of the largest Hall magnetohydrodynamics simulations to date, with system sizes up to 104 ion skin depths (di). It is demonstrated that the plasmoid instability can facilitate the onset of rapid Hall reconnection, in a regime where the onset would otherwise be inaccessible because the Sweet–Parker width is significantly above di. However, the topology of Hall reconnection is not inevitably a single stable X-point. There exists an intermediate regime where the single X-point topology itself exhibits instability, causing the system to alternate between a single X-point geometry and an extended current sheet with multiple X-points produced by the plasmoid instability. Through a series of simulations with various system sizes relative to di, it is shown that system size affects the accessibility of the intermediate regime. The larger the system size is, the easier it is to realize the intermediate regime. Although our Hall magnetohydrodynamics (MHD) model lacks many important physical effects included in fully kinetic models, the fact that a single X-point geometry is not inevitable raises the interesting possibility for the first time that Hall MHD simulations may have the potential to realize reconnection with geometrical features similar to those seen in fully kinetic simulations, namely, extended current sheets and plasmoid formation.