On wind-type flows in astrophysical jets. I - The initial relativistic acceleration

Abstract

The initial acceleration of jet plasma emerging from the funnel of an accretion disk in orbit about a compact central object is investigated analytically, extending the treatment of Ferrari et al. (1984), based on the quasi-two-dimensional Navier-Stokes equations, to the relativistic case for an optically thin jet. The transonic wind-type solutions are shown to depend strongly on the geometry of the funnel and the radiation field within it, with the possibility of multiple critical points, supersonic flow in the vicinity of the central object, and multiple transonic solutions (connected by shock transitions) for a single set of input parameters. Numerical results are presented in diagrams, tables, and graphs.