large-scale collimation and stability of jets.'
author:
- |
    X. Hernandez$^1$, Pablo. L. Rendón$^2$, Rosa G. Rodríguez-Mota$^2$, A. Capella$^3$\
    $^1$Instituto de Astronomía, Universidad Nacional Autónoma de México, Apartado Postal 70–264 C.P. 04510 México D.F. México.\
    $^2$Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Apartado Postal 70–186,\
    México D.F. 04510, México.\
    $^3$Instituto de Matematicas, Universidad Nacional Autónoma de México, México D.F. 04510, México
date: 'Released 28/02/2011'
title:
- 
- A Hydrodynamical Mechanism for Generating Astrophysical Jets
---

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accretion, accretion discs — hydrodynamics — protoplanetary disks — galaxies: jets — ISM: jets and outflows

Introduction {#intro}
============

Astrophysical jets occur over a large range of astrophysical scales, from the stellar Newtonian scales of HH objects (e.g. Reipurth & Bally 2001), to the relativistic cases of microquasars and gamma ray bursts (e.g. Mirabel & Rodriguez 1999, Mészáros 2002), to the Mega-parsec extragalactic scales of AGN jets (e.g. Marscher et al. 2002). Although the processes of propagation and collimation appear to be relatively well understood in terms of the interplay between the hydrodynamics of the problem (Scheuer 1997) and magnetic fields (e.g. Blandford 1990), the precise mechanism of jet generation probably remains as the most uncertain part of the 