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

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dc.contributor.advisor Clarke, David A.
dc.creator Ramsey, Jonathan Paul 2012-05-29T11:35:09Z 2012-05-29T11:35:09Z 2011
dc.identifier.other QB466 J46 R36 2011
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.description.provenance Submitted by Katie Quinn ( on 2012-05-29T11:35:09Z No. of bitstreams: 0 en
dc.description.provenance Made available in DSpace on 2012-05-29T11:35:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2011 en
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 Doctor of Philosophy in Astronomy Doctoral Astronomy and Physics Saint Mary's University (Halifax, N.S.)
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