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dc.contributor.advisorJarboe, Thomas Ren_US
dc.contributor.authorHansen, Christopher Jamesen_US
dc.date.accessioned2014-04-30T16:21:50Z
dc.date.available2014-04-30T16:21:50Z
dc.date.issued2014-04-30
dc.date.submitted2014en_US
dc.identifier.otherHansen_washington_0250E_12854.pdfen_US
dc.identifier.urihttp://hdl.handle.net/1773/25420
dc.descriptionThesis (Ph.D.)--University of Washington, 2014en_US
dc.description.abstractThe HIT-SI experiment studies Steady Inductive Helicity Injection (SIHI) for the purpose of forming and sustaining a spheromak plasma. A spheromak is formed in a nearly axisymmetric flux conserver, with a bow tie cross section, by means of two semi-toroidal injectors. The plasma-facing surfaces of the device, which are made of copper for its low resistivity, are covered in an insulating coating in order to operate in a purely inductive manner. Following formation, the spheromak flux and current are increased during a quiescent period marked by a decrease in the global mode activity. A proposed mechanism, Imposed Dynamo Current Drive (IDCD), is expected to be responsible for this phase of quiescent current drive. Due to the geometric complexity of the experiment, previous numerical modeling efforts have used a simplified geometry that excludes the injector volumes from the simulated domain. The effect of helicity injection is then modeled by boundary conditions on this reduced plasma volume. The work presented here has explored and developed more complete computational models of the HIT-SI device. This work is separated into 3 distinct but complementary areas: 1) Development of a 3D MHD equilibrium code that can incorporate the non-axisymmetric injector fields present in HIT-SI and investigation of equilibria of interest during spheromak sustainment. 2) A 2D axisymmetric MHD equilibrium code that was used to explore reduced order models for mean-field evolution using equations derived from IDCD theory including coupling to 3D equilibria. 3) A 3D time-dependent non-linear MHD code that is capable of modeling the entire plasma volume including dynamics within the injectors. Although HIT-SI was the motivation for, and experiment studied in this research, the tools and methods developed are general — allowing their application to a broad range of magnetic confinement experiments. These tools constitute a significant advance for modeling plasma dynamics in devices with complex boundary geometries.en_US
dc.format.mimetypeapplication/pdfen_US
dc.language.isoen_USen_US
dc.rightsCopyright is held by the individual authors.en_US
dc.subjectFinite Element; Helicity injection; MHD; Multi-grid; Plasma; Spheromaken_US
dc.subject.otherPlasma physicsen_US
dc.subject.otherAerospace engineeringen_US
dc.subject.otherApplied mathematicsen_US
dc.subject.otheraeronautics and astronauticsen_US
dc.titleMHD Modeling in Complex 3D Geometries: Towards Predictive Simulation of SIHI Current Driveen_US
dc.typeThesisen_US
dc.embargo.termsNo embargoen_US


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