Plasma Physics (Physics/ECE/NE 922) Seminars |
Events on Monday, October 22nd, 2018
- Dalton Schnack Memorial Lecture: Three-dimensional Coherent Plasmoids in Current-Carrying Plasmas
- 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)