Other
Scientific paper
May 2007
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007phdt........42m&link_type=abstract
Thesis (PhD) Trinity College Dublin, 2007
Other
Ism: Herbig-Haro Objects, Ism: Individual Objects: Ldn 1551 Irs 5, Ism: Jets And Outflows, Stars: Formation
Scientific paper
In the previous fifty years it has become clear that jets and outflows play a vital role in the formation of stars and compact objects. Jets from young stellar objects typically show Herbig-Haro knots and bow shocks. Additionally, it now appears that (1) most stars form in binaries, and (2) jets from young stars are multiple and episodic outflows. Several groups have carried out large-scale simulations of jets, but often assuming a uniform ambient medium and a single disk and star. In this thesis the problems associated with non-uniform media and binary systems are explored. In order to understand the role of jets in star formation the questions are asked: how do jets from binary stars behave? What is the effect of the prehistory of jets on their collimation, acceleration and morphology? To answer these questions, a parallel adaptive-grid magnetohydrodynamics code, ATLAS, is modified to include optically thin atomic radiative cooling losses. The code is rigorously tested, with particular reference to the shock-capturing and the radiative cooling. The tests used include one-dimensional shock-tube tests, two-dimensional blast waves, double Mach reflection of a strong shock from a wedge, the overstable radiatively cooling shock, and the Orszag-Tang vortex. A comparison of the code with another code, PLUTO, for the type of jet problems solved in this thesis is also performed. Using ATLAS, the propagation of jets in complex environments is studied. The first ever simulations of binary jets are performed. Three aspects of the problem are studied, the effects of source orbiting, the effects of interaction, and the role of the magnetic field. It is shown that jets from binary stars can interact and the signature of the interaction is demonstrated. The negligible effect of source orbiting is demonstrated. A toroidal magnetic field is placed in the ambient environment and further accentuates the interaction. Following on from this work, the evolution of the jet when the environment is not uniform is studied. Simulations have been performed which track the evolution of a jet in an partially evacuated cavity. The parameter space of the problem is explored in axisymmetry. The strong effect of the cavity on the recollimation, the acceleration and the radiative cooling losses is demonstrated.
No associations
LandOfFree
Three-dimensional models of astrophysical magnetohydrodynamical jets does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Three-dimensional models of astrophysical magnetohydrodynamical jets, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Three-dimensional models of astrophysical magnetohydrodynamical jets will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1743337