Do plasmoids induce fast magnetic reconnection in well-resolved current sheets in 2D MHD simulations?

Abstract

We investigate the development of tearing-mode instability using the highest-resolution two-dimensional magnetohydrodynamic simulations of reconnecting current sheets performed on a uniform grid, for Lundquist numbers of $10^3\le S\le 5\times 10^5$ , reaching up to $65,536^2$ grid cells. We demonstrate a Sweet--Parker scaling of the reconnection rate $V_{\text{rec}}\sim S^{-1/2}$ up to Lundquist numbers $S\sim 10^4$. For larger values of Lundquist number, between $2\times 10^4\le S\le 2\times 10^5$, plasmoid formation sets in, leading to a slight enhancement of the reconnection rate, $V_{\text{rec}}\sim S^{-1/3}$, consistent with the prediction from linear tearing mode induced reconnection, indicating that reconnection remains resistivity-dependent and therefore slow. In this range of $S$-values, the plasmoids do not undergo a merger cascade, as they are rapidly advected out of the reconnection layer. Only for $S>2\times 10^5$, we observe the nonlinear development of the tearing-mode instability, with plasmoid coalescence and a saturation of the reconnection rate at $V_{\text{rec}}/V_A\sim 0.01$. At such high $S$, however, the corresponding Reynolds number is large, reaching $\text{Re}>2000$ even on scales comparable to the current-sheet thickness. We therefore conclude that, in astrophysical systems, it is essential to account for the dominant influence of turbulence and three-dimensional effects in the reconnection process.

Accepted for publication in ApJ. 25 pages, 17 figures, 1 table

References in corpus (41)

• Reconnection in a Weakly Stochastic Field
• The Internal-Collision-Induced Magnetic Reconnection and Turbulence (ICMART) Model of Gamma-Ray Bursts
• Instability of current sheets and formation of plasmoid chains
• Fast Reconnection in High-Lundquist-Number Plasmas Due to Secondary Tearing Instabilities
• Fast TeV variability in blazars: jets in a jet
• Fast magnetic reconnection in the plasmoid-dominated regime
• Numerical Tests of Fast Reconnection in Weakly Stochastic Magnetic Fields
• Scaling laws of resistive magnetohydrodynamic reconnection in the high-Lundquist-number, plasmoid-unstable regime
• Formation of Plasmoid Chains in Magnetic Reconnection
• Phase Diagram for Magnetic Reconnection in Heliophysical, Astrophysical and Laboratory Plasmas
• Magnetic reconnection and stochastic plasmoid chains in high-Lundquist-number plasmas
• 3D Turbulent Reconnection: Theory, Tests and Astrophysical Implications
• Extreme particle acceleration in magnetic reconnection layers. Application to the gamma-ray flares in the Crab Nebula
• Turbulent Magnetohydrodynamic Reconnection Mediated by the Plasmoid Instability
• UHECRs from magnetic reconnection in relativistic jets
• Radiative Properties of Reconnection-Powered Minijets in Blazars
• Turbulent Magnetic Reconnection in Two Dimensions
• A Numerical Simulation of the Reconnection Layer in 2D Resistive MHD
• Plasmoid Instability in Evolving Current Sheets and Onset of Fast Reconnection
• Statistics of Reconnection-Driven Turbulence
• Ideal GLM-MHD: About the entropy consistent nine-wave magnetic field divergence diminishing ideal magnetohydrodynamics equations
• The role of magnetic reconnection on jet/accretion disk systems
• Reconnection Studies Under Different Types of Turbulence Driving
• The role of fast magnetic reconnection on the radio and gamma-ray emission from the nuclear regions of microquasars and low luminosity AGNs
• Three-dimensional Spontaneous Magnetic Reconnection
• The tearing mode instability of thin current sheets: the transition to fast reconnection in the presence of viscosity
• Particle acceleration by relativistic magnetic reconnection driven by kink instability turbulence in Poynting flux dominated jets
• PIC methods in astrophysics: Simulations of relativistic jets and kinetic physics in astrophysical systems
• Extended theory of the Taylor problem in the plasmoid-unstable regime
• MHD instabilities in accretion disks and their implications in driving fast magnetic reconnection
• A magnetic reconnection model for explaining the multi-wavelength emission of the microquasars Cyg X-1 and Cyg X-3
• On the Kelvin-Helmholtz instability with smooth initial conditions -- Linear theory and simulations
• Fast magnetic reconnection structures in Poynting-flux dominated jets
• Three-dimensional Turbulent Reconnection within Solar Flare Current Sheet
• Evolution, structure and topology of self-generated turbulent reconnection layers
• Oblique tearing mode instability: guide field and Hall effect
• Magnetic Field Effects near the launching region of Astrophysical Jets
• Magnetic reconnection mediated by hyper-resistive plasmoid instability
• Reconnection in weakly stochastic B-fields in 2D
• Particle acceleration by magnetic reconnection in relativistic jets: the transition from small to large scales
• Investigating Turbulence Effects on Magnetic Reconnection Rates Through Three-Dimensional Resistive Magnetohydrodynamical Simulations