Under the basic assumption that the observed turbulent motions in molecular clouds are Alfvénic waves or turbulence, we emphasize that the Doppler broadening of molecular line profiles directly measures the velocity amplitudes of the waves instead of the Alfvén velocity. Assuming an equipartition between the kinetic energy and the Alfvénic magnetic energy, we further propose the hypothesis that...

A detailed account of the theoretical and experimental study of thermal instability (Bénard convection) in Newtonian fluids, under varying assumptions of hydrodynamics and hydromagnetics, has been treated in detail by Chandrasekhar [1]. The use of Boussinesq approximation has been made throughout, which states that the density may be treated as a constant in all the terms in the equations of mo...

In this, the rst of a series of three papers, we begin a detailed description of ZEUS-2D, a numerical code for the simulation of uid dynamical ows in astrophysics including a self-consistent treatment of the e ects of magnetic elds and radiation transfer. The algorithms in ZEUS-2D divide naturally into three areas: 1) hydrodynamics (HD), 2) magnetohydrodynamics (MHD), and 3) radiation hydrodyna...

Boundary layer behavior over a moving continuous surface is an important type of flow occurring in several engineering processes. For example, many metallurgical processes involve the cooling of continuous strips or filaments by drawing them through a quiescent fluid. However, by drawing such strips in an electrically conducting fluid subject to a magnetic field, the rate of cooling can be cont...

In this paper, the effect of magnetic field on double-diffusive convection in couple-stress fluid saturating a porous medium is considered. By applying linear stability theory and normal mode analysis method, a necessary condition is derived which states that the viscoelastic double-diffusive convection at marginal state, cannot manifest as stationary convection if the thermal Rayleigh number R...

This paper deals with the theoretical investigation of the thermal instability of a thin layer of electrically conducting micropolar rotating fluid, heated from below in the presence of uniform vertical magnetic field in porous medium. A dispersion relation is obtained for a flat fluid layer, contained between two free boundaries using a linear stability analysis theory, and normal mode analysi...

We construct models of core-collapse supernovae in one spatial dimension, including rotation, angular momentum transport, and viscous dissipation employing an α-prescription. We compare the evolution of a fiducial 11 M⊙ non-rotating progenitor with its evolution including a wide range of imposed initial rotation profiles (1.25<P0 < 8 s, where P0 is the initial, approximately solid-body, rotatio...

We relate entropy and magnetic field perturbations to variations of solar p-mode eigenfrequencies. The frequency variations result from changes in path length and propagation speed. These produce shifts of opposite sign. Path length changes dominate for entropy perturbations, and propagation speed changes dominate for most types of magnetic field perturbations. The p-mode frequencies increased ...

It is suggested in this paper that the ‘bare’ strange star might be not bare, and there could be a magnetosphere around it. As a strange star might be an intensely magnetized rotator, the induced unipolar electric field would be large enough to construct a magnetosphere around the strange matter core. This kind of magnetosphere is very similar to that of the rotating magnetized neutron stars di...