Current-sheet evolution near a hyperbolic magnetic neutral line in Hall magnetohydrodynamics (MHD) is investigated. An exact analytical solution describing a self-similar evolution is given. This solution shows a hastening of the current-sheet formation process at intermediate times by the Hall effect but subsequently a quenching by the Hall effect of the finite-time singularity exhibited in id...

The advent of robust, reliable and accurate higher order Godunov schemes for many of the systems of equations of interest in computational astrophysics has made it important to understand how to solve them in multi-scale fashion. This is so because the physics associated with astrophysical phenomena evolves in multi-scale fashion and we wish to arrive at a multi-scale simulational capability to...

The kinetic evolution of the Orszag–Tang vortex is studied using collisionless hybrid simulations. In magnetohydrodynamics MHD this configuration leads rapidly to broadband turbulence. At large length scales, the evolution of the hybrid simulations is very similar to MHD, with magnetic power spectra displaying scaling similar to a Kolmogorov scaling of 5/3. At small scales, differences from MHD...

Non-solitonic examples of the application of geometrical and topological methods in plasma physics and magnetohydrodynamics (MHD) are given. The first example considers the generalization of magnetic helicity to gravitational torsion loop. The second example considers also the application of this same torsion loop metric to some problems of helical fields in MHD dynamo theory. In the last examp...

The magnetohydrodynamics angular rate sensor (MHD ARS) has received much attention for its ultra-low noise in ultra-broad bandwidth and its impact resistance in harsh environments; however, its poor performance at low frequency hinders its work in long time duration. The paper presents a modified MHD ARS combining Coriolis with MHD effect to extend the measurement scope throughout the whole ban...

A new approximate Riemann solver for the equations of magnetohydrodynamics (MHD) with an isothermal equation of state is presented. The proposed method of solution draws on the recent work of Miyoshi and Kusano, in the context of adiabatic MHD, where an approximate solution to the Riemann problem is sought in terms of an average constant velocity and total pressure across the Riemann fan. This ...

In this work, the gas-kinetic method (GKM) is enhanced with resistive and Hall magnetohydrodynamics (MHD) effects. Known as MGKM (for MHD–GKM), this approach incorporates additional source terms to the momentum and energy conservation equations and solves the magnetic field induction equation. We establish a verification protocol involving numerical solutions to the one-dimensional (1D) shock t...

A new code, named MAP, is written in FORTRAN language for magnetohydrodynamics (MHD) calculation with the adaptive mesh refinement (AMR) and Message Passing Interface (MPI) parallelization. There are several optional numerical schemes for computing the MHD part, namely, modified Mac Cormack Scheme (MMC), Lax-Fridrichs scheme (LF) and weighted essentially non-oscillatory (WENO) scheme. All of th...

Recent discoveries of the intriguing " jet-torus " structure in the Crab Neb-ula and other pulsar nebulae prompted calls for reexamining of their theory. The most radical proposals involve abolishing of the MHD approximation altogether and developing of purely electromagnetic models. However, the classical MHD models of the Crab Nebula were hampered by the assumption of spherical symmetry made ...

A new numerical code, called SFUMATO, for solving self-gravitational magnetohydrodynamics (MHD) problems using adaptive mesh refinement (AMR) is presented. A block-structured grid is adopted as the grid of the AMR hierarchy. The total variation diminishing (TVD) cell-centered scheme is adopted as the MHD solver, with hyperbolic cleaning of divergence error of the magnetic field also implemented...