Current profile control by ac magnetic helicity injection is computationally investigated in a reversed field pinch ~RFP!. Three-dimensional resistive magnetohydrodynamics ~MHD! computation is employed to study the nonlinear MHD. During ac helicity injection, when toroidal and poloidal surface voltages are oscillated out of phase, the parallel electric field is maintained positive over a majori...

The properties of linear Alfvén, slow, and fast magnetoacoustic waves for uniform plasmas in relativistic magnetohydrodynamics (MHD) are discussed, augmenting the well-known expressions for their phase speeds with knowledge on the group speed. A 3 + 1 formalism is purposely adopted to make direct comparison with the Newtonian MHD limits easier and to stress the graphical representation of their...

We study the magnetohydrodynamics (MHD) equations with anisotropic ion pressure and isotropic electron pressure under both the classical and semirelativistic approximations in order to develop a numerical model. The dispersion relation as well as the characteristic wave speeds are derived. In addition to the exact wave speed solutions, we also provide efficient approximate formulas for the semi...

Magnetohydrodynamics (MHD), the science of the motion of an electrically conducting fluid in the presence of a magnetic field, consists essentially of the interaction between the fluid velocity and the magnetic field. Electric currents induced in the fluid as a result of its motion modify the field; at the same time their flow in the magnetic field leads to mechanical forces which modify the mo...

In this paper we perform an analysis of the wave structure of the ideal magnetohydrodynamic (MHD) equations. We present an analytical expression of the nonlinearity term associated to each characteristic field derived from a scaled version of the complete system of eigenvectors proposed by Brio andWu [M. Brio, C.C. Wu, An upwind differencing scheme for the equations of ideal magnetohydrodynamic...

Coronal seismology, a new field of solar physics that emerged over the last 5 years, provides unique information on basic physical properties of the solar corona. The inhomogeneous coronal plasma supports a variety of magnetohydrodynamics (MHD) wave modes, which manifest themselves as standing waves (MHD oscillations) and propagating waves. Here, we briefly review the physical properties of obs...

Different variants of hybrid kinetic-fluid models are considered for describing the interaction of a bulk fluid plasma obeying magnetohydrodynamics (MHD) and an energetic component obeying a kinetic theory. Upon using the Vlasov kinetic theory for energetic particles, two planar Vlasov-MHD models are compared in terms of their stability properties. This is made possible by the Hamiltonian struc...

Unsteady Hall Magnetohydrodynamics (MHD) near a hyperbolic magnetic neutral line is investigated. An exact analytical solution describing a self-similar evolution is given. This solution shows a negligible impact on the current-sheet formation process near the hyperbolic magnetic neutral line at small times by the Hall effect but, subsequently, a quenching by the Hall effect of the finite-time ...

We investigate the question of whether ambipolar diffusion (ion-neutral drift) determines the smallest length and mass scale on which structure forms in a turbulent molecular cloud. We simulate magnetized turbulence in a mostly neutral, uniformly driven, turbulent medium, using a three-dimensional, two-fluid, magnetohydrodynamics (MHD) code modified from Zeus-MP. We find that substantial struct...

In this paper, we validate the boundary layer theory for 2D steady viscous incompressible magnetohydrodynamics (MHD) equations in a domain { ( X , Y ) ∈ [ 0 L ] × R + } under assumption of moving at = . The validity expansions and convergence rates are established Sobolev sense. We extend results case with shear outer ideal MHD flows [3] to nonshear flows.