Temperature gradient driven heat flux closure in fluid simulations of collisionless reconnection

Abstract

Recent efforts to include kinetic effects in fluid simulations of plasmas have been very promising. Concerning collisionless magnetic reconnection, it has been found before that damping of the pressure tensor to isotropy leads to good agreement with kinetic runs in certain scenarios. An accurate representation of kinetic effects in reconnection was achieved in a study by Wang et al. (Phys. Plasmas, volume 22, 2015, 012108) with a closure derived from earlier work by Hammett and Perkins (PRL, volume 64, 1990, 3019). Here, their approach is analyzed on the basis of heat flux data from a Vlasov simulation. As a result, we propose a new local closure in which heat flux is driven by temperature gradients. That way, a more realistic approximation of Landau damping in the collisionless regime is achieved. Previous issues are addressed and the agreement with kinetic simulations in different reconnection setups is improved significantly. To the authors' knowledge, the new fluid model is the first to perform well in simulations of the coalescence of large magnetic islands.

14 pages, 7 figures

References in corpus (7)

• Instability of current sheets and formation of plasmoid chains
• A Review of the 0.1 Reconnection Rate Problem
• Kinetic Vlasov Simulations of collisionless magnetic Reconnection
• Comparison of time splitting and backsubstitution methods for integrating Vlasov's equation with magnetic fields
• Coupled Vlasov and two-fluid codes on GPUs
• Two-Stage Bulk Electron Heating in the Diffusion Region of Anti-Parallel Symmetric Reconnection
• Enhanced conservation properties of Vlasov codes through coupling with conservative fluid models

Cited by in corpus (15)

• Magnetic reconnection in the era of exascale computing and multiscale experiments
• Exact and Locally Implicit Source Term Solvers for Multifluid-Maxwell Systems
• Drift instabilities in thin current sheets using a two-fluid model with pressure tensor effects
• Machine-learning heat flux closure for multi-moment fluid modeling of nonlinear Landau damping
• Using the maximum entropy distribution to describe electrons in reconnecting current sheets
• An extended MHD study of the 16 October 2015 MMS diffusion region crossing
• An Energy Conserving Vlasov Solver That Tolerates Coarse Velocity Space Resolutions: Simulation of MMS Reconnection Events
• The muphyII Code: Multiphysics Plasma Simulation on Large HPC Systems
• A conservative implicit-PIC scheme for the hybrid kinetic-ion fluid-electron plasma model on curvilinear meshes
• Electron cyclotron drift instability and anomalous transport: two-fluid moment theory and modeling
• Fluid Simulations of Three-Dimensional Reconnection that Capture the Lower-Hybrid Drift Instability
• A Parallel-Kinetic-Perpendicular-Moment Model for Magnetized Plasmas
• Anisotropic Heating and Parallel Heat Flux in Electron-only Magnetic Reconnection with Intense Guide Fields
• Optimal Landau-type closure parameters for two-fluid simulations of plasma turbulence at kinetic scales
• Multiphysics simulations of collisionless plasmas