A direct numerical simulation of a strong relativistic collisionless shock propagating into an unmagnetized medium has been performed in two spatial dimensions. It is found that: (i) collisionless shock exists, (ii) particle acceleration is insignificant, (iii) the shock does not generate “quasi-static” magnetic fields, contrary to recent claims by other authors. All our results agree with a si...

Collisionless shocks are pervasive in space and astrophysical plasmas and are known to be efficient particle accelerators; however, the microphysics underlying shock formation and particle acceleration is not yet fully understood. The fast progress in laser technology is bringing the study of near-relativistic collisionless shocks into the realm of laboratory plasmas. We use multi-dimensional p...

Recently, high-resolution Chandra observations revealed the existence of very sharp features in the Xray surface brightness and temperature maps of several clusters (Vikhlinin et al., 2001). These features, called “cold fronts”, are characterized by an increase in surface brightness by a factor ∼> 2 over 10-50 kpc, accompanied by a drop in temperature of a similar magnitude. The existence of su...

abstract in present paper has tried to examine and investigate quality of effectiveness of monetary shocks on the growth of agricultural sector by using time series dataes of iran economy during 1960-2006 , filter hodric-prescott method and liner regressive models. the resultes show that qualily of effectiveness monetary shocks on growth of agricultural sector is asymmetric and length of effect...