Non-ideal magnetohydrodynamics on a moving mesh

Marinacci, Federico; Vogelsberger, Mark; Kannan, Rahul; Mocz, Philip; Pakmor, Rüdiger; Springel, Volker

doi:10.1093/mnras/sty397

Cited by 123 publications

(127 citation statements)

References 75 publications

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“…feedback from AGN, as shown by the comparison between non-radiative and "full physics" runs. Using a Lagrangian finite volume method, Marinacci et al (2015Marinacci et al ( , 2018a showed magnetic 2018field seeding and evolution with the "Illustris" subgrid model for galaxy formation, also including explicit diffusivity. They obtained μG magnetic fields in clusters when they included seeding from galaxy feedback (Fig.…”

Section: Cosmological Simulations Of Magnetic Fields In Galaxy Clustersmentioning

confidence: 99%

Magnetic Field Amplification in Galaxy Clusters and Its Simulation

et al. 2018

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We review the present theoretical and numerical understanding of magnetic field amplification in cosmic large-scale structure, on length scales of galaxy clusters and beyond. Structure formation drives compression and turbulence, which amplify tiny magnetic seed fields to the microGauss values that are observed in the intracluster medium. This process is intimately connected to the properties of turbulence and the microphysics of the intracluster medium. Additional roles are played by merger induced shocks that sweep through the intra-cluster medium and motions induced by sloshing cool cores. The accurate simulation of magnetic field amplification in clusters still poses a serious challenge for simulations of cosmological structure formation. We review the current literature on cosmological simulations that include magnetic fields and outline theoretical as well as numerical challenges.

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Section: Cosmological Simulations Of Magnetic Fields In Galaxy Clustersmentioning

confidence: 99%

Magnetic Field Amplification in Galaxy Clusters and Its Simulation

et al. 2018

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“…Similar configurations have also been used in the context of nonideal MHD to measure reconnection rates (see e.g. Marinacci et al 2018, and references therein).…”

Section: Current Sheet Problemmentioning

confidence: 99%

High-order magnetohydrodynamics for astrophysics with an adaptive mesh refinement discontinuous Galerkin scheme

Guillet

Pakmor

Springel

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Modern astrophysical simulations aim to accurately model an ever-growing array of physical processes, including the interaction of fluids with magnetic fields, under increasingly stringent performance and scalability requirements driven by present-day trends in computing architectures. Discontinuous Galerkin methods have recently gained some traction in astrophysics, because of their arbitrarily high order and controllable numerical diffusion, combined with attractive characteristics for high performance computing. In this paper, we describe and test our implementation of a discontinuous Galerkin (DG) scheme for ideal magnetohydrodynamics in the AREPO-DG code. Our DG-MHD scheme relies on a modal expansion of the solution on Legendre polynomials inside the cells of an Eulerian octree-based AMR grid. The divergencefree constraint of the magnetic field is enforced using one out of two distinct cell-centred schemes: either a Powell-type scheme based on nonconservative source terms, or a hyperbolic divergence cleaning method. The Powell scheme relies on a basis of locally divergence-free vector polynomials inside each cell to represent the magnetic field. Limiting prescriptions are implemented to ensure non-oscillatory and positive solutions. We show that the resulting scheme is accurate and robust: it can achieve high-order and low numerical diffusion, as well as accurately capture strong MHD shocks. In addition, we show that our scheme exhibits a number of attractive properties for astrophysical simulations, such as lower advection errors and better Galilean invariance at reduced resolution, together with more accurate capturing of barely resolved flow features. We discuss the prospects of our implementation, and DG methods in general, for scalable astrophysical simulations.

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“…The implementation makes use of Arepo's MHD capabilities (Pakmor et al 2011;Pakmor & Springel 2013) and is the latest addition to a suite of non-ideal physics options in Arepo. These options already include effects such as isotropic viscosity (Muñoz et al 2013), cosmic ray transport (Pakmor et al 2016b;Pfrommer et al 2017), anisotropic heat conduction (Kannan et al 2016), Ohmic diffusion (Marinacci et al 2018) and radiation transport (Kannan et al 2019).…”

Section: Algorithmmentioning

confidence: 99%

Braginskii viscosity on an unstructured, moving mesh accelerated with super-time-stepping

Berlok

Pakmor

Pfrommer

2019

Monthly Notices of the Royal Astronomical Society

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We present a method for efficiently modelling Braginskii viscosity on an unstructured, moving mesh. Braginskii viscosity, i.e., anisotropic transport of momentum with respect to the direction of the magnetic field, is thought to be of prime importance for studies of the weakly collisional plasma that comprises the intracluster medium (ICM) of galaxy clusters. Here anisotropic transport of heat and momentum has been shown to have profound consequences for the stability properties of the ICM. Our new method for modelling Braginskii viscosity has been implemented in the moving mesh code Arepo. We present a number of examples that serve to test the implementation and illustrate the modified dynamics found when including Braginskii viscosity in simulations. These include (but are not limited to) damping of fast magneto-sonic waves, interruption of linearly polarized Alfvén waves by the firehose instability and the inhibition of the Kelvin-Helmholtz instability by Braginskii viscosity. An explicit update of Braginskii viscosity is associated with a severe time step constraint that scales with (∆x) 2 where ∆x is the grid size. In our implementation, this restrictive time step constraint is alleviated by employing 2nd order accurate Runge-Kutta-Legendre super-time-stepping. We envision including Braginskii viscosity in future large-scale simulations of Kelvin-Helmholtz unstable cold fronts in cluster mergers and AGNgenerated bubbles in central cluster regions.

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Non-ideal magnetohydrodynamics on a moving mesh

Cited by 123 publications

References 75 publications

Magnetic Field Amplification in Galaxy Clusters and Its Simulation

Magnetic Field Amplification in Galaxy Clusters and Its Simulation

High-order magnetohydrodynamics for astrophysics with an adaptive mesh refinement discontinuous Galerkin scheme

Braginskii viscosity on an unstructured, moving mesh accelerated with super-time-stepping

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