General Physics Seminar 22 January 2004


MHD simulations of Astrophysical Jets

Fabien Casse
FOM Institute for Plasma Physics 'Rijnhuizen', Nieuwegein, The Netherlands


Across cosmos, among stars and galaxies, well-focused flows called jets are very peculiar phenomena heralding of particular stages in the life of stars. Their formation, composition and structure are still a matter of debate and of great importance for the formation of stars. These outflows are also occuring around ``compact'' objects (neutron stars, black holes) which are relics of a star explosion. These so-called jets are composed of ionized gas interacting with magnetic field, allowing a magnetohydrodynamical description.

In this colloquium, after giving a large introduction about the astrophysical systems involved, I will present MHD simulations of these flows done within the Numerical Plasma Dynamics team. In particular, I will explain how a MHD collimated jet can be launched from the surrounding magnetized medium of a star or a black hole and illustrate the collimating effect of the large-scale magnetic field acting within the jet.