Particle-acceleration and Radiation in the Turbulent Flow of a Jet, A&A, 345, 653, 1999


We present a numerical model for particle-electron- acceleration and radiation inside the body of an extragalactic jet. We model the jet environment as a turbulent medium generating non-linear structures (eddies and/or shocks) through a cascading process. These structures act like in-situ accelerators for the electrons, initially injected from the central engine. Two types of acceleration processes are considered: second order Fermi acceleration and shock drift acceleration depending on the velocity of the non-linear structures encountered.
We study the modulation of the energy distribution of electrons in such an environment, by incorporating synchrotron radiation losses at the time intervals between successive interactions of the particles with the turbulent structures. By performing a parametric study with respect to the level of turbulent activity and the time intervals between interactions, we calculate the temporal evolution of the cut-off frequency of the synchrotron radiation spectrum of the particles and discuss our results in connection to recent observations.

keywords : Acceleration of particle - Shock waves - Turbulence - synchrotron radiation