Analytic Model of MHD Hollow-Cone Jets

Abstract

We propose an analytic model of MHD jets in which the jet plasma is confined to a skin layer of a cone with small opening angle. The confinement is due to the magnetic pressures of the poloidal field in the core region ofthis narrow cone and of the toroidal field on the outside. The latter field is generated by the poloidal electric current driven in the accretion disk and returns through the polar jet regions. The jet is gradually accelerated by the magnetic force, at most, only to a mildly relativistic speed. In this process, the radial Poynting flux in the jet is converted into the kinetic flux of the radial outflow.