NUMERICAL-SIMULATION OF 2D JETS WITH TIME-DEPENDENT DIRECTION OF EJECTION

Jets from young stars often show sinuous structures or apparent changes of direction in the plane of the sky. These effects can be interpreted as being the direct consequence of a time-dependent direction of ejection from the source. To analyse this possible interpretation, we have computed adiabatic and nonadiabatic 2D jets from sources with a time-dependent ejection direction. From these numerical simulations, we have obtained a qualitative description of the general characteristics of such flows. We have also obtained emission-line intensity maps which appear to share at least some of the observational characteristics of stellar jets. A simulation of the complete structure of an adiabatic wiggling jet is presented. From it we extract information about the general structure, velocities, the shock formation and evolution, knot formation and motion, and finer structure at the head of the jet. A 'close-up' of the body of a non-adiabatic wiggling jet is also presented. Maps of emission from this flow are calculated and compared with observational data.