Magnetic coordinates for hydromagnetic equilibria are defined which treat toroidal and "straight" helical plasmas equivalently and yet exploit the existence of a continuous symmetry to derive relations between various geometrical and physical qualities. This allows the number of equilibrium quantities which must be known to be reduced to a minimal, or primitive, set. Practical formulas for vari...

It is widely known that cosmic magnetic fields, including the fields of planets, stars, and galaxies, are produced by the hydromagnetic dynamo effect in moving electrically conducting fluids. It is less well known that cosmic magnetic fields play also an active role in cosmic structure formation by enabling outward transport of angular momentum in accretion disks via the magnetorotational insta...

In this paper we study a simple model consisting of a dilute fully ionized plasma in the presence of the gravitational and a constant magnetic field to analyze the propagation of hydromagnetic instabilities. In particular we show that the so called Jeans instability is in principle affected by the presence of the magnetic field. A brief discussion is made attempting to assess this influence in ...

The paper presents a mathematical analysis of the stability of generalized hydromagnetic thermal shear flows in the Presence of horizontal magnetic field. The physical configuration is that of a horizontal layer of an incompressible inviscid heat conducting fluid of zero electrical resistivity in which there is a differential streaming in the horizontal direction and density variation in the ve...

Abstract In the Bénard convection governed nanofluid confined between two horizontal infinite free-free boundaries, effect of Hall current is investigated when it subjected to constant vertical magnetic field. The Buongiorno mathematical model for hydromagnetic flow with currents has been considered. Brownian motion effects and thermophoresis nanoparticles have included in energy equation. A re...

Recent progress in astrophysical hydromagnetic turbulence is being reviewed. The physical ideas behind the now widely accepted Goldreich–Sridhar model and its extension to compressible magnetohydrodynamic turbulence are introduced. Implications for cosmic ray diffusion and acceleration is being discussed. Dynamo-generated magnetic fields with and without helicity are contrasted against each oth...

We examine the hydromagnetic stability of magnetically confined mountains, which arise when material accumulates at the magnetic poles of an accreting neutron star. We extend a previous axisymmetric stability analysis by performing three-dimensional simulations using the ideal-magnetohydrodynamic (ideal-MHD) code zeus-mp, investigating the role played by boundary conditions, accreted mass, stel...

Z. Naturforsch. 54 a, 411-416 (1999); received April 19, 1999 The effects of collisions with neutral atoms on the hydromagnetic stability of the plane interface separating two streaming superposed composite plasmas of uniform densities in a porous medium are investigated. In the absence of fluid velocities, it is found, for a potentially stable configuration, that the system remains stable, whi...

We propose a gamma-ray burst scenario involving relativistic jets dominated by Poynting flux with alternating toroidal magnetic fields. Such a structure may arise naturally if the jet is formed and powered by the accretion flow in the core of a collapsar. We conjecture that the polarity of the toroidal magnetic field changes randomly due to hydromagnetic turbulence driven by the magneto-rotatio...