The strong inhomogeneities in plasma parameters in the ionosphere and adjacent regions can trap waves in the upper end of the ULF range (Pc1/Pi1). The topside ionosphere is characterized by a rapidly increasing Alfvén speed with a scale height the order of 1000 km. Shear mode Alfvén waves in this region can be partially trapped at frequencies in the 0.1-1.0 Hz range. The same structure can trap...

In the presence of the primordial magnetic field, initial vector (vorticity) perturbations produce cosmological Alfvén waves and leave imprints on cosmic microwave background (CMB) temperature and polarization anisotropy. We have investigated imprints of cosmological Alfvén waves in CMB anisotropy. For data constraints, we have used the power spectrum of the recent CMB observations, and correla...

The discovery of magnetohydrodynamic waves was a major breakthrough in plasma physics and its applications to space physics and fusion research. The waves were discovered by Hannes Alfvén and are therefore also called Alfvén Waves. The discovery was typical of Alfvén’s outstanding ability to derive results of great generality from analysis of specific problems—in this case, the sunspots and the...

A study of the generation of zonal flows and zonal magnetic fields by finite beta drift waves and kinetic drift-Alfvén waves is presented. The analysis is a generalization of recent investigations of the modulational instability for zonal flow generation by electrostatic drift waves to finite beta drift waves and kinetic drift-Alfvén waves. The drift wave driven unstable zonal flows/fields are ...

Aims. To explore the solar coronal heating enigma by an analytical and numerical study of the enhanced phase mixing of harmonic Alfvén waves propagating in gravitationally stratified coronal structures of varying magnetic field divergence. Methods. Corrected analytical solutions are derived to model the dissipation of Alfvén waves propagating in divergent and stratified coronal structures. Thes...

Aims. In the approximation of linear dissipative magnetohydrodynamics (MHD) it can be shown that driven MHD waves in magnetic plasmas with high Reynolds number exhibit a near resonant behaviour if the frequency of the wave becomes equal to the local Alfvén (or slow) frequency of a magnetic surface. This near resonant behaviour is confined to a thin region, known as the dissipative layer, which ...

The interstellar medium (ISM) of star-forming galaxies is magnetized and turbulent. Cosmic rays (CRs) propagate through it, those with energies from ? GeV ? TeV are likely subject to the streaming instability, whereby wave damping processes balances excitation resonant ionic Alfvén waves by CRs, reaching an equilibrium in which propagation speed CRs very close local ion velocity. transport ther...

We simulate incompressible, MHD turbulence using a pseudo-spectral code. Our major conclusions are as follows. 1) MHD turbulence is most conveniently described in terms of counter propagating shear Alfvén and slow waves. Shear Alfvén waves control the cascade dynamics. Slow waves play a passive role and adopt the spectrum set by the shear Alfvén waves. Cascades composed entirely of shear Alfvén...

The competition of the linear and nonlinear damping mechanisms for phase-mixed Alfvén waves in the solar corona is studied. It is shown that the nonlinear damping of the phasemixed Alfvén waves due to their parametric decay is stronger than both collisional and Landau damping for waves with frequencies below a critical frequency which depends on the wave amplitude. This critical frequency is cl...

By performing three-dimensional magnetohydrodynamic simulations including Alfvén eigenmode perturbations most unstable to the ionospheric feedback effects, we examined the auroral vortex street that often appears just before substorm onset. We found that an initially placed arc splits, intensifies, and rapidly deforms into a vortex street. We also found that there is a critical convection elect...