Jarboe, Thomas RBenedett, Thomas Edwin2020-10-262020-10-262020-10-262020Benedett_washington_0250E_22215.pdfhttp://hdl.handle.net/1773/46365Thesis (Ph.D.)--University of Washington, 2020Magnetic field configurations used for magnetic confinement of plasmas are often preferred to be simple in form, with symmetry sufficient to reduce their effective dimensionality to two or fewer, as with tokamak plasmas or ideal spheromak equilibria. In practice, three-dimensional effects may be unavoidable due to experimental geometry, especially in the case of the Steady Inductive Helicity Injection (SIHI) experiments HIT-SI, HIT-SI3, and the upcoming HIT-SIU, that necessarily impose nonaxisymmetric perturbations on the plasma for current drive. The effects of boundary shapes on plasma behavior will be studied in three parts, using the 3D magnetohydrodynamic (MHD) code PSI-Tet that solves equations on unstructured tetrahedral grids and is capable of simulating plasmas within arbitrary shapes: the first is an exploration of nonaxisymmetric boundary shapes, as well as nonaxisymmetric magnetic boundary conditions, on the ideal pressureless Taylor state equilibria that form the theoretical foundations for the targeted behavior of spheromak plasmas; the causes and limits of these effects are shown. The second is a study of the application of a single-temperature, dynamic-pressure Hall MHD model in PSI-Tet to the simulation of HIT-SI; the results of this model are compared to simulations of HIT-SI using an earlier constant-pressure model in PSI-Tet, as well as the (axisymmetric boundary) NIMROD code, and experimental HIT-SI data, finding that the new "finite-beta" model agrees with most, but not all, experimental trends. The third is an application of the single-temperature finite-beta Hall MHD model in PSI-Tet to a study of different SIHI geometries (HIT-SI, HIT-SI3, and HIT-SIU) under equivalent simulated conditions to explore the influence of boundary shapes on simulated operating SIHI devices, with differences in performance noted and traced back to particular device features. These studies mark a significant step forward in the field of the exploration of SIHI plasma dynamics in complicated geometries.application/pdfen-USCC BYBoundary ConditionsComputational Plasma PhysicsEquilibriaHelicity InjectionMHDSpheromaksPlasma physicsAerospace engineeringComputational physicsAeronautics and astronauticsThesis