Evolution of source-intrinsic parameters for an overpressured jet, d_k ≠ 1, (left panels) and for a conical jet, d_k = 1, (right panels). The upper panels show the variation in the jet width, R, in pc along the jet; the middle panels the evolution of the magnetic field, B, in G; and the bottom panels the variation ointhe upper and lower electron Lorentz factors, γ_min,max. The solid and dashed red lines correspond to a model where we take both synchrotron and adiabatic losses into account. To demonstrate the influence of radiative losses, we also computed the evolution of the electron Lorentz factor only for adiabatic losses (solid and dashed lines in bottom panels). See text for more details. The bottom x-axis is drawn in pc, and to allow for the direct comparison with the observations we plotted the upper x-axis in mas.