Into the void : simulations of protostellar jets from Keplerian discs extended to observational length scales

Show simple item record

dc.contributor.advisor Clarke, David A.
dc.creator Ramsey, Jonathan Paul
dc.date.accessioned 2012-05-29T11:35:09Z
dc.date.available 2012-05-29T11:35:09Z
dc.date.issued 2011
dc.identifier.other QB466 J46 R36 2011
dc.identifier.uri http://library2.smu.ca/xmlui/handle/01/23837
dc.description xxii, 218 leaves : ill. (some col.) ; 29 cm. en_CA
dc.description Includes abstract.
dc.description Includes bibliographical references (leaves 208-218).
dc.description.abstract In this work, I present the first simulations to investigate the formation and propagation of protostellar jets that simultaneously include the launching mechanism at < 0.1 AU and the much larger observational length scales at > 10[superscript 3] AU. This is accomplished through the development and application of AZEuS , a new adaptive mesh refinement (AMR) version of the ZEUS-3D magnetohydrodynamics (MHD) fluid code. AMR has been adapted for a fully-staggered mesh, and a description of the methods employed is given. By simulating protostellar jets over 5 orders of magnitude in length, I find relationships between conditions at the disc surface and observable quantities such as jet proper motion, rotational velocity, jet radius, and mass, momentum, kinetic energy, and angular momentum fluxes. I also find that two mechanisms for jet launching are required to understand the simulation results. For strong fields, the traditional magneto-centrifugal mechanism is applicable, while for weak fields, the jet is accelerated by gradients in toroidal magnetic pressure. The jets presented here establish a magnetically-dominated region early in their evolution, regardless of the initial magnetic field strength, implying that plasma-β < 1 is required for jet launching to occur. Over time, the plasma-β [arrow right] 1, and the jets approach equipartition between thermal pressure and magnetic forces. These results demonstrate that outflows launched magnetically from discs are capable, by themselves, of producing realistic protostellar jets. en_CA
dc.language.iso en en_CA
dc.publisher Halifax, N.S. : Saint Mary's University en_CA
dc.subject.lcc QB466.J46
dc.subject.lcsh Astrophysical jets -- Mathematical models
dc.subject.lcsh Protostars
dc.subject.lcsh Accretion (Astrophysics)
dc.title Into the void : simulations of protostellar jets from Keplerian discs extended to observational length scales en_CA
dc.type Text en_CA
thesis.degree.name Doctor of Philosophy in Astronomy
thesis.degree.level Doctoral
thesis.degree.discipline Astronomy and Physics
thesis.degree.grantor Saint Mary's University (Halifax, N.S.)


Files in this item

 
 

This item appears in the following Collection(s)

Show simple item record