Seminars

Rotating flows are traditionally produced using mechanical motion, but electromagnetic body forces provide an alternative way to drive rotation without moving hardware. In electromagnetic plasma centrifuges (EMPCs), azimuthal motion is generated through Lorentz forcing rather than rotating walls, allowing rotational speeds that are not limited by material strength. Unlike conventional shear centrifuges, these systems also operate as reactive environments, where plasma-driven chemistry can modify feedstocks during operation while rotation is sustained. This ability to simultaneously drive rotation and induce chemical reactions introduces opportunities beyond conventional separation, but the achievable separation potential is ultimately constrained by how electromagnetic forcing interacts with thermal transport and dissipation within the flow. In this work, rotating plasmas in coaxial geometries are examined where current-driven electromagnetic forces produce azimuthal bulk motion, with particular attention given to the balance between electromagnetic drive and coupled thermal processes such as viscous dissipation, Joule heating, anisotropic response, and ionization-dependent transport. To study this behaviour, a reduced two-temperature magnetohydrodynamic framework is developed to model steady rotating plasmas while retaining the first-order physical processes that influence momentum and energy transport. Model predictions are compared to experimental measurements obtained across multiple discharge regimes, demonstrating that the dominant scaling trends in rotation and heating are captured with reasonable fidelity. Once validated, the framework is used to map how magnetic field strength, current density, and geometry combine to determine achievable separation performance. The resulting trends show that attainable rotation is fundamentally governed by the competition between rotational kinetic energy and thermally mediated dissipation, and that Hartmann-number-based scaling provides a useful way to distinguish regimes where electromagnetic forcing effectively drives rotation from those where viscous and thermal losses dominate the flow response.


Bio: Drue P. Hood-McFadden is a Ph.D. candidate in Aerospace Engineering and Engineering Mechanics at the University of Texas at Austin. His research focuses on rotating plasmas, magnetohydrodynamic flows, and reactive plasma systems, combining laboratory experiments with reduced order modelling.