We have investigated imprints of cosmological Alfvén waves in Cosmic Microwave Background(CMB) anisotropy. For data constraints, we have used the power spectrum of the recent CMB observations, and correlations estimated from WMAP Internal Linear Combination (ILC) maps. Our analysis shows 3σ evidence of cosmological Alfvén waves. Using the 3σ limit from our analysis and the Alfvén velocity limit...

In this talk we introduce our recent results of global 1D MHD simulations for the acceleration of solar and stellar winds. We impose transverse photospheric motions corresponding to the granulations, which generate outgoing Alfvén waves. The Alfvén waves effectively dissipate by 3-wave coupling and direct mode conversion to compressive waves in density-stratified atmosphere. We show that the co...

We present MHD numerical simulations of the propagation of Alfvén waves in inhomogeneous magnetic fields whose topology consists of two-dimensional X-points threaded by a nonvanishing normal component. The coupling of the waves with the background field gradients leads to the development of fast-mode shock trains propagating normal to the average normal magnetic field. The fronts occur with a f...

Westudy the heating of 2-D coronal arcades by linear resonant Alfvén waves that are excited by photospheric footpoint motions of the magnetic field lines. The analysis is restricted to toroidally polarised footpoint motions so that Alfvén waves are excited directly. At the magnetic surfaces where Alfvén waves, travelling back and forth along the loop-like magnetic field lines, are in phase with...

Using Particle-In-Cell simulations i.e. in the kinetic plasma description the discovery of a new mechanism of parallel electric field generation was recently reported. Here we show that the electric field generation parallel to the uniform unperturbed magnetic field can be obtained in a much simpler framework using the ideal magnetohydrodynamics (MHD) description. In ideal MHD the electric fiel...

We investigate the interaction of magnetohydrody-namic waves with plasma density inhomogeneities. Our numerical study of the full MHD equations shows that: (A) Plasma density inhomogeneities are a source of non-linear generation of transverse com-pressive waves by a plane Alfvén wave, and substantially enhance (by about a factor of 2) the generation of the longitudinal compressive waves. (B) At...

Hannes Alfvén predicted the existence of a hydrodynamic wave in a perfectly conducting fluid in 1942. It took six years before this discovery was accepted and ten years before Alfvén waves were first observed in the laboratory. Now it is widely recognized that these waves are ubiquitous in space plasmas and are the means by which information about changing currents and magnetic fields are commu...

[1] The authors of a recent paper [Jones and Su, 2008] have used two-fluid plasma theory [e.g., Streltsov et al., 1998] to predict the parallel electric field strength of a shear Alfvén wave traveling through the Jovian magnetosphere from the vicinity of Io to the Jovian ionosphere. [2] Two-fluid analyses give adequate predictions for the parallel electric field strength Ek in plasma regimes wh...

We investigate the structure and dynamics of the M87 jet based on multi-frequency VLBI observations and MHD jet theories. Millimeter VLBI cores are considered as innermost jet emissions. The jet structure up to ∼ 105 rs is described as a parabolic streamline, indicating the lateral expansion under a confinement by the stratified ISM. Thus, the jet collimation maintains in five orders of magnitu...

[1] In a magnetized plasma with two ion species, shear Alfvén waves (or guided electromagnetic ion cyclotron waves) have zero parallel group velocity and experience a cut‐off near the ion‐ion hybrid frequency. Since the ion‐ion hybrid frequency is proportional to the magnetic field, it is possible, in principle, for a magnetic well configuration to behave as an Alfvén wave resonator in a two‐io...