Recently the shallow water magnetohydrodynamic ~SMHD! equations have been proposed for describing the dynamics of nearly incompressible conducting fluids for which the evolution is nearly two-dimensional ~2D! with magnetohydrostatic equilibrium in the third direction. In the present paper the properties of the SMHD equations as a nonlinear system of hyperbolic conservation laws are described. C...

High-cadence multiwavelength optical observations were taken with the Dunn Solar Telescope at the National Solar Observatory, Sacramento Peak, accompanied by Advanced Stokes Polarimeter vector magnetograms. A total of 11 network bright points (NBPs) have been studied at different atmospheric heights using images taken in wave bands centered on Mg i b1 0.4 Å, H , and Ca ii K3. Wavelet analysis w...

A two-dimensional isothermal collisional drift-wave turbulence model including magnetic fluctuations is studied numerically. The model has as limits the electrostatic collisional drift-wave and two-dimensional magnetohydrodynamic systems. The electromagnetic and electrostatic regimes for thermal gradient-driven ~drift-wave! turbulence are decided by the parameter b̂5(4pnT/B)(Ls /Ln ), where Ls a...

Recent observations of polar plumes in the southern solar coronal hole by the Extreme-Ultraviolet Imaging Telescope (EIT) on board the SOHO spacecraft show signatures of quasi-periodic compressional waves with periods of 10È15 minutes. The relative wave amplitude was found to increase with height in the plumes up to about 1.2 Using a one-dimensional linear wave equation for the magnetosonic R _...

Aims. The influence of a toroidal magnetic field on the dynamics of Rossby waves in a thin layer of ideal conductive fluid on a rotating sphere is studied in the " shallow water " magnetohydrodynamic approximation for the first time. Methods. Dispersion relations for magnetic Rossby waves are derived analytically in Cartesian and spherical coordinates. Results. It is shown that the magnetic fie...

A simple, compact, and systematic derivation is given of the characteristic properties of the magnetohydrodynamic ~MHD! equations with two independent variables ~time-dependent MHD in the xt plane and steady MHD in the xy plane!, based on the symmetrizable Galilean invariant form of the equations and using a matrix approach. A numerically obtained stationary planar field-aligned MHD bow shock f...

We analyze 3D numerical simulations of driven incompressible magnetohydrodynamic (MHD) turbulence in a periodic box threaded by a moderately strong external magnetic field. We find that the time scale for the energy cascade is consistent with the Goldreich-Sridhar model of strong MHD turbulence. Using higher order longitudinal structure functions we show that the turbulent motions in the plane ...

Highlights of studies of ULF waves from 1995 to early 1997 are presented. The subjects covered include (1) Pc 3±5 waves excited by sources in the solar wind, with emphasis on the role of the magnetospheric cavity in modifying the external source and establishing its own resonances, and the role of the plasmapause in magnetohydrodynamic wave propagation; (2) Pi 2 waves, with emphasis on the plas...