Lecture Notes in Physics edition:791 pages:179-199
To investigate stability properties of astrophysical jets, high-resolution numerical simulations are nowadays used routinely. In this chapter, we address jet stability issues using two complementary approaches: one where highly idealized, classical magnetohydrodynamic (MHD) “jet” configurations are simulated in detail, and one where the full complexity of relativistic jet flows is mimicked computationally. In the former, we collect vital insights into multi-dimensional MHD evolutions, where we start from simple planar, magnetized shear flows to eventually model full three dimensional, helically magnetized jet segments. Such a gradual approach allows an in-depth study of the nonlinear interaction of multiple, linearly unstable modes; as well as their potential to steepen into shocks with intricate shock–shock interactions. All these return to varying degree in the latter approach, where jets are impulsively injected into the simulation domain, and followed over many dynamical timescales. In particular, we review selected recent insights gained from relativistic AGN jet modeling. There, we cover both relativistic hydro and magnetohydrodynamic simulations. In all these studies, the use of grid-adaptive codes suited for modern supercomputing facilities is illustrated.