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We study the stability of large amplitude, circularly polarized Alfv\'en waves in an anisotropic plasma described by the double-adiabatic/CGL closure, and in particular the effect of a background thermal pressure anisotropy on the…

Space Physics · Physics 2017-12-27 Anna Tenerani , Marco Velli , Petr Hellinger

Using the WMAP cosmic microwave background data it is shown that collisions between Alfven wave packets and the cascades generated by these collisions (the Iroshnikov model) can determine the photon temperature fluctuations for arcminute…

Astrophysics · Physics 2009-11-10 A. Bershadskii , K. R. Sreenivasan

We investigate the influence of cosmic magnetic fields on gravitational wave perturbations, and find exact solutions on large scales. We show that a large-scale magnetic field can generate large-scale non-decaying gravitational waves. In…

Astrophysics · Physics 2009-11-06 Roy Maartens , Christos Tsagas , Carlo Ungarelli

Bulk motions of electrons along the line of sight induce secondary temperature fluctuations in the post-decoupling, reionized universe. In the presence of a magnetic field not only the scalar mode but also the vector mode act as a source…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-11 Kerstin E. Kunze

We examine the role of Alfven wave damping in heating the plasma in the magnetic funnels of magnetospheric accretion models of young stars. We study four different damping mechanisms of the Alfven waves: nonlinear, turbulent,…

Astrophysics · Physics 2015-05-27 M. J. Vasconcelos , V. Jatenco-Pereira , R. Opher

We consider anisotropic magnetized cosmologies filled with conductive plasma fluid and study the implications of metric perturbations that propagate parallel to the ambient magnetic field. It is known that in the first order (linear)…

General Relativity and Quantum Cosmology · Physics 2010-10-27 A Kuiroukidis , K Kleidis , D B Papadopoulos

Inflation generates gravitational waves, which may be observable in the low multipoles of the cosmic microwave background (cmb) anisotropy but only if the inflaton field variation is at least of order the Planck scale. Such a large…

High Energy Physics - Phenomenology · Physics 2009-10-28 David H. Lyth

We present a theory for the generation of mesoscale ($kr_{g}\ll 1$, where $r_{g}$ is the cosmic ray gyroradius) magnetic fields during diffusive shock acceleration. The decay or modulational instability of resonantly excited Alfven waves…

Astrophysics · Physics 2008-11-26 P. H. Diamond , M. A. Malkov

Large-scale magnetic fields affect the scalar modes of the geometry whose ultimate effect is to determine the anisotropies of the Cosmic Microwave Background (CMB in what follows). For the first time, a consistent numerical approach to the…

Astrophysics · Physics 2010-04-29 Massimo Giovannini , Kerstin E. Kunze

The evolution of Alfven turbulence due to three-wave interactions is discussed using kinetic theory for a collisionless, thermal plasma. There are three low-frequency modes, analogous to the three modes of compressible MHD. When only Alfven…

Astrophysics · Physics 2009-11-11 Q. Luo , D. B. Melrose

In the energy range from ~ 10^12 eV to ~ 10^15 eV, the Galactic cosmic ray flux has anisotropies both on large scales, with an amplitude of the order of 0.1%, and on scales between ~ 10 and ~ 30 degrees, with amplitudes smaller by a factor…

High Energy Astrophysical Phenomena · Physics 2015-03-19 G. Giacinti , G. Sigl

We propose a scenario for the quasi-periodic oscillations observed in magnetar flares wherein a tangled component of the stellar magnetic field introduces nearly isotropic stress that gives the fluid core of the star an effective shear…

Solar and Stellar Astrophysics · Physics 2015-03-05 Bennett Link , C. Anthony van Eysden

Cosmic microwave background anisotropies provide a vast amount of information on both structure formation in the universe and the background dynamics and geometry. The full physical content and detailed structure of anisotropies can be…

Astrophysics · Physics 2018-01-29 Wayne Hu , Naoshi Sugiyama , Joseph Silk

We investigate the anisotropy of Alfv\'enic turbulence in the inertial range of slow solar wind and in both driven and decaying reduced magnetohydrodynamic simulations. A direct comparison is made by measuring the anisotropic second-order…

Space Physics · Physics 2012-08-20 C. H. K. Chen , A. Mallet , T. A. Yousef , A. A. Schekochihin , T. S. Horbury

The cosmic microwave background (CMB) temperature autocorrelations, induced by a magnetized adiabatic mode of curvature inhomogeneities, are computed with semi-analytical methods. As suggested by the latest CMB data, a nearly…

Astrophysics · Physics 2008-11-26 Massimo Giovannini

Strong magnetic fields in the cores of stars are expected to significantly modify the behavior of gravity waves: this is likely the origin of suppressed dipole modes observed in many red giants. However, a detailed understanding of how such…

Solar and Stellar Astrophysics · Physics 2023-05-17 Nicholas Z. Rui , Jim Fuller

We study the impact of kinks on the cosmic microwave background (CMB) anisotropies generated by cosmic string networks. To do so, we extend the Unconnected Segment Model to describe the stress-energy tensor of a network of cosmic strings…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-02 Rodrigo P. Silva , Lara Sousa , Ivan Yu. Rybak

We performed three-dimensional magnetohydrodynamic simulations of shear Alfven waves in a full field line system with magnetosphere-ionosphere coupling and plasma non-uniformities. Feedback instability of the Alfven resonant modes showed…

Space Physics · Physics 2015-06-23 Yasutaka Hiraki

Recent observations of the cosmic microwave background (CMB) have extended the measured power spectrum to higher multipoles $l\gtrsim$1000, and there appears to be possible evidence for excess power on small angular scales. The primordial…

Astrophysics · Physics 2009-02-19 D. Yamazaki , K. Ichiki , T. Kajino , G. J. Mathews

A large-scale cosmic magnetic field affects not only the growth of density perturbations, but also rotational instabilities and anisotropic deformation in the density distribution. We give a fully relativistic treatment of all these…

Astrophysics · Physics 2008-11-26 Christos Tsagas , Roy Maartens