2025MNRAS.543.4342N

We developed the full magnetohydrodynamical analytical jet model that allows accurate reproducing of a transversal and longitudinal structure for a highly collimated relativistic jets. This model can be used as a set-up for convenient solution of radiative transfer equations and modelling the total intensity and polarization maps. We show that the analytical fits are in excellent agreement with the numerical solutions of full magnetohydrodynamical equations. Our approach allows setting easily different models for an emitting plasma number density. For example, we show that the equipartition number density ranges from several to tens of per cent of a total number density. We show that the Doppler-corrected emissivity distribution behave in such a way that we may expect a limb brightened intensity pattern on a sub-parsec scale and a spine-brightened structure downstream. We reproduce the broken power-law dependence of a jet pressure at its boundary from the jet radius. The corresponding power exponents are in agreement with the parabola-to-cone transition observed directly in nearby sources.