Department of Physics
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Plasma Physics (Physics/ECE/NE 922) Seminars
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Frontiers in Linear and Nonlinear Plasma Physics
Date: Monday, February 24th
Time: 12:05 pm - 12:55 pm
Place: 2241 Chamberlin Hall
Speaker: Jeff Parker, Lawrence Livermore National Laboratory
Abstract: This talk will highlight two areas of progress involving linear and nonlinear plasma physics. In the first half I will discuss zonal flows, a pervasive phenomenon in the universe and a prominent example of nonlinear self-organization and pattern formation. The coexistence of zonal flow and turbulence remains incompletely understood, as coherent zonal structures spontaneously break the oft-assumed symmetries of homogeneity and isotropy and profoundly alter the character of turbulent flow. Moreover, intense practical interest in zonal flows has arisen because they are believed to regulate the deleterious turbulence that degrades confinement in magnetic fusion devices. A recent statistical approach has led to breakthroughs in the theoretical understanding of zonal flow, with a systematic framework offering an analytically tractable, self-consistent model that captures many features of zonal flow behavior. Plasma physics also offers insight into zonal flow in gas giants, as considerations from MHD may explain recent measurements of the zonal-flow termination depth of 3,000 km in Jupiter.

In the second half, I will discuss how even linear physics can surprise us with new and rich phenomena. Topological phases of matter were recognized by the 2016 Nobel Prize and are now a large subject in condensed matter physics and photonics. I will present the first applications of these ideas to plasma physics with two examples: (1) A topological gaseous plasmon polariton at the surface between a magnetized plasma and vacuum, and (2) the Reversed-Shear Alfvén Eigenmode, well known in tokamaks. The new field of topological plasma waves represents a multifaceted research frontier with fundamental questions to be addressed by theory, simulation, and experiment.
Host: Jan Egedal
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