Events During the Week of September 22nd through September 29th, 2024
Monday, September 23rd, 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
- Experimental and Modeling Results from the HSX Stellarator
- Time: 12:05 pm - 1:00 pm
- Place: 1610 Engineering Hall
- Speaker: Alexis Wolfmeister, University of Wisconsin-Madison
- Abstract: The Helically Symmetric eXperiment (HSX) is an optimized stellarator with a major radius of 1.2 m and a 1 Tesla magnetic field located in Engineering Hall here at UW-Madison. Previous work has shown that the unique quasi-helical magnetic field configuration of HSX allows for large intrinsic flows in the direction of symmetry [1] and reduces neoclassical transport [2] so that transport is predominantly driven by trapped electron mode turbulence [3].HSX is equipped with a set of auxiliary coils which are used to study the effects of magnetic field geometry on plasma confinement.
Excellent plasma performance has been achieved following an intensive first wall reset, which involved removing coatings deposited on the plasma facing stainless steel wall, combined with a new vessel baking system and extensive glow discharge cleaning. The resulting reduction in impurity content has driven substantial improvements in plasma profiles, including core electron temperatures well above 2 keV and higher overall energy confinement.
During studies with different main-ion species, more pronounced electron temperature profile peaking has been measured in hydrogen fueled plasmas than with helium fueling. This is consistent with non-linear GENE [4] simulations which predict reduced turbulent heat fluxes in hydrogen plasmas. Although previous work suggested the strong electron temperature peaking observed in the core of HSX is a result of turbulent suppression by ExB flow shear, recent analysis of correlation ECE measurements have shown increased radiation temperature fluctuations in regions with high electron temperature gradients. These measurements show qualitative agreement with non-linear gyrokinetic flux tube simulations with GENE.
[1] A. Briesemeister et al., 2010 Contrib. Plasma Phys. 50 8
[2] J. Canik et al., 2007 Phys. Rev. Lett. 98 8
[3] W. Guttenfelder et al., 2008 Phys. Rev. Lett. 101 21
[4] F. Jenko et al., 2000 Phys. Plasmas 7 1904
[5] M.J. Gerard et al., 2023 Nucl. Fusion 63 056004
*Work supported by US DOE Grant No. DE-FG02-93ER54222 - Host: John Sarff
Tuesday, September 24th, 2024
- Wisconsin Quantum Institute
- Quantum Coffee Hour
- Time: 3:00 pm - 4:00 pm
- Place: Rm.5294, Chamberlin Hall
- Abstract: Please join us for the WQI Quantum Coffee today at 3PM in the Physics Faculty Lounge (Rm.5294 in Chamberlin Hall). This series, which takes place approximately every other Tuesday, aims to foster a casual and collaborative atmosphere where faculty, post-docs, students, and anyone with an interest in quantum information sciences can come together. There will be coffee and treats.
- Careers for Physicists
- Fusion Forward: Commercializing Fusion Technology in Wisconsin
- Time: 4:30 pm - 5:45 pm
- Place: Wisconsin Energy Institute, 1552 University Ave., or via Zoom (see website for reg info)
- Speaker: Various, Various
- Abstract: Recent technological breakthroughs, favorable policies, and increased investment have brightened the prospects for fusion energy, a long-studied and promising source of cheap, pollution-free, and virtually limitless power. As several startup companies aim to advance fusion from the research lab to commercial reality, Wisconsin is well positioned to become an economic hub for this groundbreaking technology. However, the journey to commercialization is complex and lengthy. Join us for an engaging discussion with Wisconsin-based fusion companies and researchers as they share both their visions for bringing fusion technology to market and the challenges they face.
Panelists:
Dominick Bindl, Vice President of Technical Development, Realta Fusion
Steffi Diem, Assistant Professor of Nuclear Engineering and Engineering Physics, UW-Madison, and a 2024 U.S. Science Envoy
Chris Hegna, Vice President of Stellarator Physics Optimization, Type One Energy
Eli Moll, Vice President and General Manager of Systems and Manufacturing, SHINE Technologies
Moderator:
Adelle Wright, Assistant Professor of Nuclear Engineering and Engineering Physics, UW-Madison
- Host: D2P
Wednesday, September 25th, 2024
- Theory Seminar (High Energy/Cosmology)
- Constraints on Kahler moduli space of 6d N=1 Supergravity
- Time: 4:00 pm - 5:30 pm
- Place: Chamberlin 5280
- Speaker: Hee-Cheol Kim, POSTECH and Harvard
- Abstract: I will discuss new constraints on 6d (1,0) supergravity theories derived from consistency conditions, including the positivity of the metric and string tensions, within the Kähler moduli spaces of their 5d reductions. The emergence of local 5d CFTs, combined with the BPS spectra of 2d strings, imposes further constraints. I will demonstrate how these conditions can be used to restrict the gauge groups and matter charges in a class of 6d supergravity theories with rank 1 gauge algebras.
- Host: Gary Shiu
Thursday, September 26th, 2024
- R. G. Herb Condensed Matter Seminar
- Electron Interactions in Rashba Materials
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Yasha Gindikin, University of Minnesota
- Abstract: We present a bunch of novel phenomena stemming from the pair spin-orbit interaction (PSOI), which does not rely on structure inversion asymmetry but instead arises from Coulomb fields of interacting electrons in materials with a strong Rashba effect. First, PSOI can induce p-wave superconducting order without the need for any mediators of attraction. Depending on the sign and strength of the PSOI coupling, two distinct superconducting phases emerge in 3D systems, analogous to the A and B phases observed in superfluid He3. In contrast, 2D systems exhibit p_x \pm i p_y order parameter, leading to the time-reversal-invariant topological superconductivity. Second, a sufficiently strong PSOI can induce ferromagnetic ordering. It is associated with a deformation of the Fermi surface, which eventually leads to a Lifshitz transition from a spherical to a toroidal Fermi surface, with a number of experimentally observable signatures. Finally, in sufficiently clean Rashba materials, ferromagnetism and p-wave superconductivity may coexist. This state resembles the A1 phase of He3, yet it may avoid nodal points due to the toroidal shape of the Fermi surface.
- Host: Alex Levchenko
- Astronomy Colloquium
- Things you should know about the Milky Way
- Time: 3:30 pm - 4:30 pm
- Place: 4421 Sterling Hall
- Speaker: Bob Benjamin, UW-Madison/UW-Whitewater
- Abstract: The last several years have seen truly remarkable advances in our understanding of the Milky Way Galaxy, from the identification of stellar streams and stellar ensembles associated with the formation history of our Galaxy to the identification and characterization of thousands of stellar clusters to the development of remarkably accurate three-dimensional maps of the distribution of interstellar dust out to three kiloparsecs from the Sun. A lot of these advances are due to the availability of high precisions parallaxes and proper motions from the ESA Gaia mission and VLBI BeSSeL program; large-scale programs of stellar spectroscopy and advances in angular resolution and sensitivity of surveys of the gas and star forming content of the Milky Way are also major contributing factors. The net effect of all of these changes is to turn the Milky Way into an excellent laboratory for studying the physical processes by which galaxies convert their gas into stars; this is occuring at the same moment as JWST observations are providing astounding external views of the same processes in nearby galaxies. In this colloquium, I will review the history of attempts to ascertain the structure of the Galaxy, highlight some of the key things we’ve learned about our Galaxy over the last few years, and provide a preview of things to come.
- Host: Melinda Soares-Furtado
Friday, September 27th, 2024
- Black and Brown in Physics
- BBiP Hispanic Heritage Month Celebration
- Time: 1:00 pm - 3:00 pm
- Place: Chamberlain 5310
- Abstract: The Black and Brown in Physics (BBiP) group would like to invite you to our first Heritage month celebration! This month we are celebrating Hispanic Heritage month. We plan on having a catered lunch (featuring Peruvian food – courtesy of the Physics department), followed by a couple of student-led presentations, and group activities (we request that you stay for both portions of the event if you plan on joining us).
The event will take place on September 27th at 1 PM in Chamberlain 5310. We also have a Zoom link for anyone who is unable to attend the event in-person:
We plan our Heritage month events to be an opportunity to learn more about a particular Heritage in a light-hearted setting (compared to our General Meetings, which tend to be more formal). We hope to see many of your there next Friday! This event is open to everyone, including allies, so please don’t hesitate on joining us! - Host: Faizah Siddique
- Physics Department Colloquium
- FASER: New Eyes for the LHC
- Time: 3:30 pm - 4:30 pm
- Place: Chamberlin 2241
- Speaker: Jonathan Feng, University of California-Irvine
- Abstract: Particle colliders have been the workhorse tool of particle physics for over 60 years, and the Large Hadron Collider at CERN has been the focus of attention for decades. Despite this, in recent years, it has become clear that the physics potential of the LHC is far from being fully explored. In particular, the existing billion dollar detectors are blind to forward collisions, which produce particles along the beamline. We now know that these collisions are a treasure trove of physics, containing the highest-energy neutrinos ever produced by humans and possible evidence for dark matter, dark sectors, milli-charged particles, and other new particles and forces. FASER, the Forward Search Experiment, was designed to cover this blind spot. Beginning in 2022, FASER detected the first neutrinos in the history of particle colliders, opening a new window on the high-energy frontier, and started searching for a variety of new particles with world-leading sensitivity. This talk will describe FASER's recent results, how they complement the traditional LHC program, and the Forward Physics Facility, a proposal to fully realize the potential of forward physics in the coming decade.
- Host: Lu Lu
