Résumé
We have applied an axisymmetric self-similar model of outflows leaving from the central corona to TTauri jets and extend this model to include relativistic motions and temperatures. For CTTS we find that the stellar jet contributes to 10 % of the total mass loss rate while the rest is provided by the 3 first stellar radii of the inner disk. Our relativistic extension allows us to model jets from black hole magnetospheres assuming a Schwarzschild metric. We intend to generalize the criterion for collimation found in the classical limit to relativistic jets from AGN.