Tensor Microwave Anisotropies from a Stochastic Magnetic Field

We derive an expression for the angular power spectrum of cosmic microwave background anisotropies due to gravity waves generated by a stochastic magnetic field and compare the result with current observations; we take into account the non-linear nature of the stress energy tensor of the magnetic field. For almost scale invariant spectra, the amplitude of the magnetic field at galactic scales is constrained to be of order 10^{-9} Gauss. If we assume that the magnetic field is damped below the Alfven damping scale, we find that its amplitude at 0.1 h^{-1}Mpc, B_\lambda, is constrained to be B_\lambda<7.9 x10^{-6} e^{3n} Gauss, for n-3/2, where n is the spectral index of the magnetic field and H_0=100h km s^{-1}Mpc^{-1} is the Hubble constant today.Comment: 6 pages, 1 figure, accepted for publication in Phys. Rev.

Effects of primordial helicity on CMB

I present here a brief overview of the effects caused by parity violating cosmological sources (such as magnetic or kinetic helicity) on the CMB fluctuations. I discuss also primordial helicity induced relic gravitational waves. All these effects can serve as cosmological tests for primordial helicity detection.Comment: for Proceedings of CMB Workshop at Irvine, March 2006; references adde

Generation of the electrostatic field in the pulsar magnetosphere plasma

The behaviour of a relativistic electron-positron plasma in the pulsar magnetosphere is investigated. The equation of the motion of the magnetospheric plasma is discussed, from which it follows that, if the plasma particle radial velocity ${V_r}>{c/{\sqrt 2}}$ (where c is the speed of light), the centrifugal acceleration changes its sign and the particle braking begins. The stability of the magnetospheric plasma with respect to the radially oriented potential perturbations is discussed and the possibility of the electrostatic field generation in this plasma along the pulsar magnetic field lines is shown.Comment: Plain LaTe