The magnetohydrodynamic ~MHD! stability of negative central magnetic shear toroidal equilibria with q.2 everywhere and ebpol@1 is investigated. Here, q is the safety factor of the equilibrium magnetic field in a torus with inverse aspect ratio e , and bpol is the ratio of the plasma pressure to the pressure in the poloidal magnetic field. At small ebpol!1, the elimination of the q52 resonant su...

Recent advances in understanding of the basic properties of compressible Magnetohydrodynamic (MHD) turbulence call for revisions of some of the generally accepted concepts. First, MHD turbulence is not so messy as it is usually believed. In fact, the notion of strong non-linear coupling of compressible and incompressible motions is not tenable. Alfven, slow and fast modes of MHD turbulence foll...

Two-dimensional (2-D) homogeneous magnetohydrodynamic (MHD) turbulence has many of the same qualitative features as three-dimensional (3-D) homogeneous MHD turbulence. These features include several ideal invariants, along with the phenomenon of broken ergodicity. Broken ergodicity appears when certain modes act like random variables with mean values that are large compared to their standard de...

The study of incompressible magnetohydrodynamic (MHD) turbulence gives useful insights on many astrophysical problems. We describe a pseudo-spectral MHD code suitable for the study of incompressible turbulence. We review our recent works on direct three-dimensional numerical simulations for MHD turbulence in a periodic box. In those works, we use a pseudo-spectral code to solve the incompressib...

[1] We have recently extended the global magnetohydrodynamic (MHD) model BATS-R-US to account for pressure anisotropy. Since the inner magnetosphere dynamics cannot be fully described even by anisotropic MHD, we coupled our anisotropic MHD model with two inner magnetospheric models: the Rice Convection Model (RCM) and the Comprehensive Ring Current Model (CRCM). The coupled models provide bette...

In preparation for an experimental study of magnetorotational instability (MRI) in liquid metal, we present non-ideal axisymmetric magnetohydrodynamic simulations of the nonlinear evolution of MRI in the experimental geometry. The simulations adopt fully insulating boundary conditions. No-slip conditions are imposed at all boundaries. A clear linear phase is observed with reduced linear growth ...

The magnetohydrodynamic (MHD) flow of third grade nanofluid between coaxial porous cylinders was investigated in this work. Two types of series solutions were presented for constant and variable viscosity. The resulting nonlinear coupled equations were solved by employing homotopy analysis method (HAM). The convergence of the series solutions has been discussed explicitly. The recurrence formul...

We compare the properties of ordinary strong magnetohydrodynamic (MHD) turbulence in a strongly magnetized medium with the recently discovered viscosity-damped regime. We focus on energy spectra, anisotropy, and intermittency. Our most surprising conclusion is that in ordinary strong MHD turbulence the velocity and magnetic fields show different high-order structure function scalings. Moreover ...

Astrophysical turbulence is magnetohydrodynamic (MHD) in its nature. We discuss fundamental properties of MHD turbulence. In particular, we discuss the generation of compressible MHD waves by Alfvenic turbulence and show that this process is inefficient. This allows us to study the evolution of different types of MHD perturbations separately. We describe how to separate MHD fluctuations into 3 ...

In an X-ray binary system, the companion star feeds the compact neutron star with plasma materials via accretions. The spinning neutron star is likely covered with a thin “magnetized ocean” and may support magnetohydrodynamic (MHD) tidal waves. While modulating the thermal properties of the ocean, MHD tidal waves periodically shake the base of the stellar magnetosphere that traps energetic part...