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Plasma Physics (Physics/ECE/NE 922) Seminars
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Dalton Schnack Memorial Lecture: Three-dimensional Coherent Plasmoids in Current-Carrying Plasmas
Date: Monday, October 22nd
Time: 12:05 pm
Place: 2241 Chamberlin Hall
Speaker: Dr. Fatima Ebrahimi, Princeton Plasma Physics Lab
Abstract: Generation of coherent, current-carrying structures is prevalent in magnetically-dominated, rotating astrophysical and laboratory plasmas. Intertwining flux tubes, as well as sheet-like structures, emerging from the surface of the sun, and edge-localized filament structures in magnetically confined plasmas are examples of such current-carrying structures. In this talk, using three-dimensional simulations, I demonstrate the onset and nonlinear evolution of coherent current-carrying filaments, as well as round magnetic structures (so called plasmoids), in a global toroidal geometry. The role of magnetic reconnection, the rearrangement of the magnetic field topology, as a major underlying mechanism for the fast growth and nonlinear saturation of the localized current-carrying structures will be explained. It will be shown that 3-D magnetic fluctuations can cause either local flux amplification to trigger axisymmetric reconnecting plasmoids formation at the reconnection site or cause the local annihilation of axisymmetric current through a fluctuation-induced, bi-directional dynamo term. The instrumental role of magnetic reconnection, which enables an innovative technique for producing current in fusion plasmas, will be discussed.

Supported in part by a generous grant from the Women in Science & Engineering Leadership Institute (WISELI)
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