Events During the Week of September 28th through October 5th, 2025
Monday, September 29th, 2025
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Centrifugal confinement in mirrors and axisymmetric scrape-off layers
- Time: 12:00 pm - 1:00 pm
- Place: 2241 Chamberlin Hall
- Speaker: Timothy Stoltzfus-Dueck, PPPL
- Abstract: In the centrifugal-mirror confinement concept, parallel confinement by the mirror force is supplemented with a parallel centrifugal force driven by supersonic ExB rotation in the azimuthal/toroidal direction. Although this approach practically closes the loss cone and naturally exhibits stabilizing ExB shear, it requires a very large radial voltage difference, presenting engineering challenges for the insulating end plates. In principle, the addition of a strong azimuthal field could reduce the required voltage, since the simple azimuthal ExB drift would be replaced by more rapid azimuthal trapped-particle precession. Also, if the mirror ratio is large enough, newly-ionized ions are accelerated to the necessary parallel velocities in their first bounce orbit, both confining and significantly heating them. Unfortunately, MHD analysis shows that the centrifugal-force-confining plasma current is purely azimuthal. This implies that only the axial magnetic field contributes to the confining magnetic pressure, severely limiting the usefulness of the azimuthal magnetic field in a beta-limited plasma scenario. However, the single-particle confinement properties may prove useful in non-beta-limited scenarios. For example, centrifugal confinement could slow parallel losses from an axisymmetric scrape-off-layer, particularly in an ST with a deeply inboard X-point. In addition to supporting large density and temperature drops from midplane to target, such confinement could substantially broaden the heat-flux deposition width, while the SOL rotation directly stabilizes resistive wall modes.
- Host: Cary Forest
Tuesday, September 30th, 2025
- Black and Brown in Physics
- BBiP General Meeting
- Time: 2:00 pm - 3:00 pm
- Place: Sterling B343
- Speaker: BBiP Executive Team
- Abstract: The Black and Brown in Physics (BBiP) student organization would like to invite you to our first general meeting of the Fall 2025 semester! During this meeting, we plan to introduce you to our new executive team, have discussions, share information about other similar student organizations on campus, and give you all a preview of our events and plans for this upcoming semester. In addition, we will also play a fun jeopardy game about famous black and brown people in history and pop culture. The general meeting will take place on Tuesday (9/30) at 2 PM in Sterling B343 (location not fixed yet, but we will reach out closer to the event date if anything changes). We will also have the option for folks to join over Zoom as well (Zoom Link:
We hope that you’ll be able to join us! This event is open to all students, staff, faculty, and postdocs. Wednesday, October 1st, 2025
- Department Meeting
- Time: 12:15 pm - 1:15 pm
- Place: B343 Sterling
- Speaker: Kevin Black, UW-Madison
- Host: Kevin Black
- Outreach
- Science Fair Pitcher Night
- Time: 6:00 pm - 7:00 pm
- Place: Library Cafe and Bar, 320 N Randall Ave, Madison, WI 53715
- Speaker: Vandenbroucke Group, UW–Madison Physics, WIPAC
- Abstract: Join the Vandenbroucke group for an evening of science talks over pitchers of beer! The Library Cafe and Bar is hosting weekly Science Fair nights, where researchers from around campus sign up to present their research in a Science Cafe style. $5 from each pitcher sold between 4-10pm goes to a group of the presenters' choice, and this week, the Vandenbroucke group picked the MMSD Planetarium.
- Host: Justin Vandenbroucke
Thursday, October 2nd, 2025
- R. G. Herb Condensed Matter Seminar
- Cavity QED with molecular defects coupled to a photonic crystal cavity
- Time: 10:00 am - 11:00 am
- Place: 5310 Chamberlin
- Speaker: Jonathan Hood, Purdue
- Abstract: We implement permanent spectral tuning to bring lifetime-limited emitters into collective resonance within an integrated photonic cavity. This addresses a fundamental challenge in solid-state cavity QED: combining multiple coherent quantum emitters with scalable nanophotonics. Our hybrid approach decouples emitter synthesis from nanophotonic fabrication using straightforward techniques that make cavity QED broadly accessible. Building on our previous demonstration of superradiance and subradiance in pairs of molecules [1], we now couple several coherent emitters to a single cavity mode through high doping densities. Optically-induced frequency shifting provides long-lived spectral control, allowing us to tune multiple molecules into resonance and demonstrate controlled formation of collective quantum states [2]. This establishes a scalable platform for many-body cavity QED and opens pathways toward chemically-designed quantum systems where optical properties are engineered through synthetic chemistry. We will also report on progress in our ultracold Li-Cs experiment, including cooling with the narrow 5D transition [3]. [1] C. Lange, E. Daggett, V. Walther, L. Huang, and J.D. Hood, Nature Physics (2024) [2] C. Lange et al., arXiv:2406.01917 (2025) [3] Blodgett et al., arXiv :2505.10540 (2025)
- Host: Mark Saffman
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Cosmic ray processes across the Universe: multi-messenger insights form Galaxies to the Cosmic Web
- Time: 2:30 pm - 3:30 pm
- Place: Chamberlin Hall, Room 5280
- Speaker: Ellis Owen, RIKEN, Japan
- Abstract: Cosmic rays interact with astrophysical systems across a vast range of scales, from turbulent galactic environments to the large-scale structure of the Universe. Closely linked to violent, high-energy processes, they act as a dynamic feedback agent, regulating the physical conditions and long-term evolution of galactic and circum-galactic ecosystems. Depending on their energy, cosmic rays can also escape from their host galaxies, propagate through the cosmic web, and produce multi-wavelength and multi-messenger signatures that encode information about their interactions, environments, and transport physics. In this talk, I will highlight key observational tracers, including those from multi-messenger probes, that can be used to map the physical effects of cosmic rays across astrophysical environments and extend studies of galaxies beyond traditional astronomical techniques. I will also examine the role of cosmic rays in shaping baryonic flows around galaxies, and discuss their fate as they traverse the magnetized large-scale structures of the Universe, including the highest-energy particles that may never reach us on Earth.
- Host: Ellen Zweibel
Friday, October 3rd, 2025
- Physics Department Colloquium
- Integrating Computation into the Undergraduate Physics Major
- Time: 3:30 pm - 4:30 pm
- Place: Chamberlin 2241
- Speaker: Shaul Hanany, University of Minnesota
- Abstract: Computation — modeling, simulating, predicting, analyzing, and displaying the behavior of physical systems — is central to physics. Yet, computation is not integrated into the US undergraduate physics curriculum. I will describe two institutional and curricular change efforts directed at integrating computation as a standard problem solving method throughout the physics major. One has been ongoing at the University of Minnesota Twin Cities for several years and the other is a nascent collaboration of 9 institutions of diverse types. ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Meet the speaker! 2:00 - 3:00 PM, 5290 Chamberlin Hall Our colloquium speaker, Prof Shaul Hanany (https://cse.umn.edu/dsi/shaul-hanany) would like to hear from students about their career plans after their current degree and about their perceptions of career prospects. He would be happy to describe his department's Career Education Program for its students (both graduates and undergraduates), to talk about his research in observational cosmology/CMB, and to discuss the colloquium topic.
- Host: Peter Timbie