Events at Physics |
Events During the Week of March 3rd through March 10th, 2024
Monday, March 4th, 2024
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Schnack Memorial Seminar: "Plasma instabilities associated with runaway electron beam and their potential influences”
- Time: 12:00 pm - 1:15 pm
- Place: 1227 Engineering Hall
- Speaker: Dr. Chang Liu, PPPL (Princeton Plasma Physics Laboratory)
- Abstract: High-energy runaway electron beams can be generated in fusion experiments during various discharge phases. Control and mitigation of runaway electron beams and reducing their energy impact on the plasma-facing walls is critical to the operation of ITER and other tokamaks. Interestingly, the high energy of these electrons can also provoke plasma instabilities, creating pathways for the electrons to dissipate energy and diffuse in space. In this presentation, I will discuss some of the common instabilities driven by runaway electrons observed in experiments and the efforts to model them. High-frequency plasma waves, such as whistler and extraordinary electron (EXEL) waves, can be stimulated by the anisotropic distribution of runaway electrons and resonating with their cyclotron motion. This resonance can lead to rapid pitch-angle scattering, manifested as an abrupt increase in electron cyclotron emission (ECE) signals. In addition, these instabilities can affect the runaway electrons' avalanche growth and raise the critical electric field for the transition from growth to decay of runaway electron population. Lower frequency plasma waves can also be excited if they resonate with the precession motion of the trapped runaway electrons. The excitation of plasma instabilities in the Alfvén frequency range has been observed in DIII-D, AUG and JET disruption experiments, and has been shown to contribute to the loss of runaway electrons during current quench. The interaction between these Alfvén oscillations in the background plasma and runaway electrons can be explored through kinetic-MHD simulations, including calculations of linear growth, nonlinear saturation, and the consequent transport of runaway electrons.
- Host: Prof. Carl Sovinec
- Theory Seminar (High Energy/Cosmology)
- tbd
- Time: 4:00 pm - 5:00 pm
- Place: 5280 Chamberlin Hall
- Speaker: tbd, tbd
- Host: Lisa Everett
Tuesday, March 5th, 2024
- No events scheduled
Wednesday, March 6th, 2024
- Undergraduate Program Event
- Physics and Astronomy Majors Fair
- Time: 4:30 pm - 5:30 pm
- Place: Chamberlin Hall Lobby
- Speaker: Evan Heintz
- Abstract: Come talk to your advisors and other majors at the Physics and Astronomy Majors Fair! At this event, you can declare the Physics or Astronomy-Physics major, or if you're already declared, come interact with other majors, sign up for clubs and outreach, and enjoy some snacks and refreshments.
- Host: Evan Heintz
Thursday, March 7th, 2024
- Astronomy Colloquium
- CANCELLED: NIRWALS: the Near InfraRed Washburn Astronomical Laboratories Spectrograph on SALT
- Time: 3:30 pm - 4:30 pm
- Place: 4421 Sterling Hall
- Speaker: Marsha Wolf, UW-Madison
- Abstract: CANCELLED
- Host: Ke Zhang
Friday, March 8th, 2024
- Physics Department Colloquium
- Using Radio Detectors to Discover the Highest Energy Astrophysical Neutrinos
- Time: 3:30 pm - 5:00 pm
- Place: 2241 Chamberlin Hall
- Speaker: Abigail Vieregg, University of Chicago
- Abstract: The detection of high energy astrophysical neutrinos is an important step toward understanding the most energetic cosmic accelerators. IceCube has observed the first astrophysical neutrinos and identified the first potential sources. However, the best sensitivity at the highest energies comes from detectors that look for coherent radio Cherenkov emission from neutrino interactions. I will give an overview of the state of current experimental efforts, and then discuss two new experiments, RNO-G and PUEO, that are currently being constructed to discover neutrinos at the highest energies and push the energy threshold for radio detection down to overlap with the energy range probed by IceCube, covering the full astrophysical energy range out to the highest energies, and opening up new phase space for discovery.
- Host: Ke Fang