On the supersonic dynamics of magnetized jets of thermal gas in radio galaxies

Abstract

A stellar-wind type formulation is developed to study axisymmetric MHD jet flows in radio galaxies. When the magnetic energy is small compared to the total energy of the jet flow and the azimuthal field has a pinching configuration, similarity methods can be used to reduce the two-dimensional partial differential equations of the problem to a system of ordinary differential equations. These solutions allow some approximate analytical solutions in the outer jet region where many parameters approach their asymptotic values, but numerical methods have to be used in the inner jet region where variables change rapidly. Numerical results on the effects of a pinching external pressure and a pinching magnetic field are discussed, and the observed width of the northern radio jet in 3C 449 is fitted by each of the two pinching models.