I consider the nonaxisymmetric linear theory of an isothermal magnetohydrodynamic (MHD) shear flow. The analysis is performed in the shearing box, a local model appropriate for a thin disk geometry. Linear perturbations in this model can be decomposed in terms of shearing waves (shwaves), which appear spatially as plane waves in a frame comoving with the shear. The time dependence of these wave...

WeakMHD turbulence consists of waves that propagate along magnetic field lines, in both directions. When two oppositely directed waves collide, they distort each other, without changing their respective energies. Each wave suffers many collisions before cascading; by contrast, in strong MHD turbulence, waves cascade on the same timescale at which they collide. ‘‘ Imbalance ’’ means that more en...

The theory of magnetically accelerated outtows and jets from accretion disks is reviewed at an introductory level, with special attention to problem areas like the launching conditions of the ow at the disk surface, stability of the magnetic eld, and collimation mechanisms. This text will appear in R. 1.1 Introduction: the case for magnetic acceleration Narrow, high speed outtows (jets) and les...

A magnetohydrodynamic (MHD) stirrer that exhibits chaotic advection is investigated experimentally and theoretically. The stirrer consists of a circular cavity with an electrode (C) deposited around its periphery. Two additional electrodes (A) and (B) are deposited eccentrically inside the cavity on the bottom. The cavity is positioned in a uniform magnetic field that is parallel to the cylinde...

A nonlinear gyrokinetic simulation model incorporating equilibrium current has been formulated for studying kinetic magnetohydrodynamic processes in magnetized plasmas. This complete formulation enables gyrokinetic simulation of both pressure-gradient-driven and current-driven instabilities as well as their nonlinear interactions in multiscale simulations. The gyrokinetic simulation model recov...

A computational study of resistive drift waves in the edge plasma of a stellarator with an helical magnetic axis is presented. Three coupled field equations, describing the collisional drift wave dynamics in the linear approximation, are solved as an initial-value problem along the magnetic field line. The magnetohydrodynamic equilibrium is obtained from a three-dimensional local equilibrium mo...

the meshless local radial point interpolation (mlrpi) method is applied to examine the magnetohydrodynamic (mhd) ow of third grade uid in a porous medium. the uid saturates the porous space between the two boundaries. several limiting cases of fundamental ows can be obtained as the special cases of present analysis. the variations of pertinent parameters are addressed.

Abstract Magnetohydrodynamic equilibrium states with a three-dimensional helical core are computed to model the MAST spherical tokamak and the RFX-mod reversed field pinch. The boundary is fixed as axisymmetric. The MAST equilibrium state has the appearance of an internal kink mode and is obtained under conditions of weak reversed central shear. The RFX-mod equilibrium state has seven-fold peri...

Linear gyrokinetic simulation of fusion plasmas finds a radial localization of the toroidal Alfvén eigenmodes (TAEs) due to the nonperturbative energetic particle (EP) contribution. The EP-driven TAE has a radial mode width much smaller than that predicted by the magnetohydrodynamic theory. The TAE radial position stays around the strongest EP pressure gradients when the EP profile evolves. The...

The critical strength of a magnetic field required for the suppression of the Richtmyer-Meshkov instability (RMI) is investigated numerically by using a two-dimensional single-mode analysis. For the cases of magnetohydrodynamic parallel shocks, the RMI can be stabilized as a result of the extraction of vorticity from the interface. A useful formula describing a critical condition for magnetohyd...