Events at Physics |
Events on Monday, September 16th, 2024
- Climate & Diversity
- Climate and Diversity Committee Open Hours
- Time: 12:00 pm - 2:00 pm
- Place: Chamberlin 5310
- Speaker: Rachel Zizmann, UW-Madison Physics
- Abstract: Open Hours are welcome for everyone in the department! During these sessions, we have the option to discuss the topic listed, that is not required or necessary for attending
- Host: Rachel Zizmann
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Hot Electron Instabilities in Magnetic Mirrors and Dipoles
- Time: 12:05 pm - 1:00 pm
- Place: 1610 Engineering Hall
- Speaker: Prof. Michael Mauel, Columbia University
- Abstract: The dedication of the new WHAM experiment, having world-record magnetic field strength, has generated renewed interest in magnetic mirror plasma confinement for fusion applications. Beginning in the early 1960's when Ray Dandl (ORNL) discovered how to efficiently couple microwaves near the electron cyclotron frequency to a mirror-confined plasma, several mirror and mirror-like experiments have observed hot electron instabilities. These instabilities are often violent and always beautifully interesting. Common to axisymmetric magnetic mirrors, bumpy tori, and levitated dipoles, hot electron instabilities always appear when the fraction of energetic electrons exceeds some threshold. In contrast, minimum-B magnetic mirrors have only whistler instabilities but do not have hot electron instabilities [Garner, PRL 1987]. When conditions are adjusted so that the hot electron fraction is low, the plasma is much colder and drift instabilities appear. Examples discussed include Shinji Hiroe's "Observation of hot electron ring instabilities in ELMO Bumpy Torus" [POF 1984], observations from the TARA tandem mirror [IAEA-CN-44/CI-4, 1984], from the Collisionless Terrella Experiment [Ben Levitt, POP 2002], and from the Levitated Dipole Experiment [Darren Garnier, POP 2006].
- Host: Cary Forest
