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We describe a Godunov-type magnetohydrodynamic (MHD) code based on the Miyoshi and Kusano (2005) solver which can be used to solve various astrophysical hydrodynamic and MHD problems. The energy equation is in the form of entropy…

Astrophysics of Galaxies · Physics 2015-12-16 A. V. Koldoba , G. V. Ustyugova , P. S. Lii , M. L. Comins , S. Dyda , M. M. Romanova , R. V. E. Lovelace

A set of reduced Hall magnetohydrodynamic (MHD) equations are used to evaluate the stability of large aspect ratio current sheets to the formation of plasmoids (secondary islands). Reconnection is driven by resistivity in this analysis,…

Plasma Physics · Physics 2015-05-30 S. D. Baalrud , A. Bhattacharjee , Y. -M. Huang , K. Germaschewski

Fully realizing the potential of multigrid solvers often requires custom algorithms for a given application model, discretizations and even regimes of interest, despite considerable effort from the applied math community to develop fully…

Plasma Physics · Physics 2023-02-22 Mark F. Adams , Matthew K. Knepley

In the outer heliosphere, beyond the solar wind termination shock, it is expected that the warped heliospheric current sheet forms a region of closely-packed, multiple, thin current sheets. Such a system may be subject to the ion-kinetic…

Space Physics · Physics 2016-05-25 David Burgess , P. W. Gingell , Lorenzo Matteini

A Grad-Shafranov equation (GSE) valid for compact quasisymmetric stellarators is derived by an asymptotic expansion around a vacuum field carried to first order. We obtain an equation for the existence of flux surfaces leading up to the…

Plasma Physics · Physics 2025-03-25 Nikita Nikulsin , Wrick Sengupta , Stefan Buller , Amitava Bhattacharjee

Numerical methods for solving the ideal magnetohydrodynamic (MHD) equations in more than one space dimension must either confront the challenge of controlling errors in the discrete divergence of the magnetic field, or else be faced with…

Numerical Analysis · Mathematics 2015-05-19 Christiane Helzel , James A. Rossmanith , Bertram Taetz

We present a new magnetohydrodynamic (MHD) simulation code with the aim of providing accurate numerical solutions to astrophysical phenomena where discontinuities, shock waves, and turbulence are inherently important. The code implements…

This paper investigates the non-resistive compressible magnetohydrodynamic (MHD) equations in $\mathbb{R}^2$. We establish the global existence and stability of classical solutions for initial data sufficiently close to a constant…

Analysis of PDEs · Mathematics 2026-05-22 Yi Zhu

We investigate the Kelvin-Helmholtz instability occuring at the interface of a shear flow configuration in 2D compressible magnetohydrodynamics (MHD). The linear growth and the subsequent non-linear saturation of the instability are studied…

Astrophysics · Physics 2009-10-31 R. Keppens , G. Toth , R. H. J. Westermann , J. P. Goedbloed

We examine the effect of accuracy of high-order spectral element methods, with or without adaptive mesh refinement (AMR), in the context of a classical configuration of magnetic reconnection in two space dimensions, the so-called…

Fluid Dynamics · Physics 2009-11-13 D. Rosenberg , A. Pouquet , P. D. Mininni

We present a finite-volume, genuinely 4th-order accurate numerical method for solving the equations of resistive relativistic magnetohydrodynamics (Res-RMHD) in Cartesian coordinates. In our formulation, the magnetic field is evolved in…

High Energy Astrophysical Phenomena · Physics 2024-07-12 Andrea Mignone , Vittoria Berta , Marco Rossazza , Matteo Bugli , Giancarlo Mattia , Luca Del Zanna , Lorenzo Pareschi

A technique is proposed for constructing three-dimensional solutions comlplying with the self-consistent magnetohydrostatic (MHS) equations and with observations along the line of sight of the magnetic field at the photosphere. The…

Astrophysics · Physics 2009-10-31 G. V. Rudenko

To systematically stress a rotationally symmetric 3D magnetic null point by advecting the opposite footpoints of the spine axis in opposite directions. This stress eventually concentrates in the vicinity of the null point forming a local…

Solar and Stellar Astrophysics · Physics 2015-05-27 K. Galsgaard , D. I. Pontin

Current sheets (CSs), long stretching structures of magnetic reconnection above solar flare loops, are usually observed to oscillate, their origins, however, are still puzzled at present. Based on a high-resolution 2.5-dimensional MHD…

Solar and Stellar Astrophysics · Physics 2023-09-11 Yulei Wang , Xin Cheng , Zining Ren , Mingde Ding

Recently, secondary island formation due to the tearing instability of the Sweet-Parker current sheet was identified as a possible mechanism that can lead to fast reconnection (less sensitive dependence on Lundquist number $S$) both in…

Solar and Stellar Astrophysics · Physics 2011-06-06 C. S. Ng , S. Ragunathan

We investigate the nonlinear instability of a smooth Rayleigh-Taylor steady-state solution (including the case of heavier density with increasing height) to the three-dimensional incompressible nonhomogeneous magnetohydrodynamic (MHD)…

Analysis of PDEs · Mathematics 2014-12-02 Fei Jiang , Song Jiang , Weiwei Wang

While it is important to design stellarators with high magneto-hydrodynamic (MHD) stability $\beta$-limit, it is also crucial to ensure that good magnetic surfaces exist in a large range of $\beta$ values. As $\beta$ increases,…

Plasma Physics · Physics 2023-05-17 A. Baillod , J. Loizu , Z. Qu , H. P. Arbez , J. P. Graves

We perform the first magnetohydrodynamic simulations in full general relativity of self-consistent rotating neutron stars (NSs) with ultrastrong mixed poloidal and toroidal magnetic fields. The initial uniformly rotating NS models are…

General Relativity and Quantum Cosmology · Physics 2022-02-23 Antonios Tsokaros , Milton Ruiz , Stuart L. Shapiro , Kōji Uryū

In this paper, we prove the non-uniform continuity of the data-to-solution map for the incompressible magnetohydrodynamic (MHD) equations with only magnetic diffusion in Sobolev spaces $H^s(\mathbb{R}^d)$ for all $s>0$ and $d=2,3$. Our…

Analysis of PDEs · Mathematics 2026-02-09 Quansen Jiu , Yaowei Xie

Sweet-Parker current sheets in high Lundquist number plasmas are unstable to tearing, suggesting they will not form in physical systems. Understanding magnetic reconnection thus requires study of the stability of a current sheet as it…

Plasma Physics · Physics 2018-03-02 Elizabeth A. Tolman , Nuno F. Loureiro , Dmitri A. Uzdensky