WOS: 000412307300014Propagation of astrophysical jets inside an ambient medium transports a large amount of energy to surrounding materials as a consequence of interactions. These interactions have a crucial effect on the evolution and dynamics of the jets. They can cause the formation of the jet's head, which dissipates its energy. In this paper, we have numerically modeled the evolution of jet's dynamics to understand the effects of the critical parameters (Mach numbers, jet velocity, densities, pressures of the accelerated the jet and medium, sound speeds, and Lorentz factor) on the head of the jet, jet-cocoon, vortexes and shocks. When the jet propagates inside the overdense region, we observe clear evidence for deceleration of the jet and find a more complex structure. In the underdense cases, almost no back-flows and cocoons are developed. We have also modeled the pulsed type jets propagating into the overdense region and found a very rich internal structure of the jet, such as cocoon, knots, vortexes, etc. They could explain the structure of jets seen in Herbig-Haro bows and XZ Tauri proto-jet
