Events at Physics |
Events During the Week of March 5th through March 12th, 2023
Monday, March 6th, 2023
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Predicting the nonlinear properties of three-dimensional magnetohydrodynamics and the applications to advanced stellarators for fusion energy
- Time: 12:00 pm
- Place: 2241 Chamberlin Hall
- Speaker: Adelle Wright, Princeton Plasma Physics Laboratory
- Abstract: Magnetohydrodynamics (MHD) is a nonlinear dynamical system rich in spatio-temporal complexity, which models the behaviour of highly ionised gases (i.e. plasmas) in the continuum limit. Stellarators, together with tokamaks, are the two leading concepts for realising fusion energy via toroidal magnetic confinement of plasmas, the macroscopic properties of which are described by nonlinear MHD.
This presentation gives an overview of recent advances in understanding and predicting the macroscopic properties of magnetically confined plasmas, particularly in the absence of continuous symmetries, through new developments in MHD theory and innovations in high-fidelity extended-MHD modelling on leadership-class computing resources, using the M3D-C1 code. We highlight progress toward developing predictive reduced models of nonlinear MHD and their applications to improve design criteria for next-generation, optimised stellarators.
A consequence of the Hamiltonian nature of magnetic field lines, the absence of a continuous symmetry in the toroidal direction can have profound impacts on plasma properties in both tokamaks and stellarators. This makes understanding and predicting nonlinear properties of three-dimensional (3D) MHD important for fusion. Clarifying the role of 3D effects is critical for determining when macroscopic instabilities are benign or have the potential to become disruptive.
Tuesday, March 7th, 2023
- No events scheduled
Wednesday, March 8th, 2023
- Theory Seminar (High Energy/Cosmology)
- Black holes and vacuum decay
- Time: 1:00 pm
- Place: Chamberlin 5280
- Speaker: Andrey Shkerin, Univ. Minnesota
- Abstract: : We will discuss the decay of a metastable vacuum catalysed by black holes. The phenomenological interest in this problem lies in the fact that our current electroweak vacuum may not be absolutely stable. Its lifetime, while sufficiently large in the present-day Universe, may be significantly reduced in extreme environments such as the vicinity of small hot primordial black holes, which could be produced abundantly in the early Universe. From the theoretical point of view, the challenge is to compute the rate of decay of the false quantum vacuum state which lives in a curved spacetime and which is generally out of thermal equilibrium. I will discuss a general method of doing so and illustrate it using toy models of dilaton black holes in two dimensions. We will see that different vacuum states associated with a black hole have parametrically different lifetimes. Hence, in computing the enhancement of the electroweak vacuum decay rate near black holes it is important to choose the physically relevant (Unruh) vacuum state. Finally, I will outline what remains to be done in the realistic case of black holes in four dimensions.
- Host: George Wojcik
Thursday, March 9th, 2023
- R. G. Herb Condensed Matter Seminar
- Single Photon Computational imaging and Quantum Information
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Andreas Velten, UW-Madison
- Host: Thad Walker
- Astronomy Colloquium
- Students Learn More from Interactive and Inclusive Teaching
- Time: 3:30 pm
- Place: 4421 Sterling Hall
- Speaker: Julia Kregenow, Penn State University
- Abstract: For over twenty years, research has consistently shown that students learn more from active learning at the college level. Yet active learning is still rarely used by university faculty. Even small changes benefit student learning. I will share practical strategies for incorporating small doses of active learning without the need to completely overhaul your course or teaching style. Furthermore, many of us have heard about growth vs. fixed mindset, and that students with a growth mindset learn more. But recent results show that a teacher’s mindset *about their students* matters just as much. Instructors who believe that success is within reach for all students lead their students to higher learning gains and higher persistence in STEM. This is particularly true for URM students, who historically have had lower retention in STEM. Lastly, I will also provide strategies to augment student motivation by articulating your goals, reducing barriers to participation, and using differentiated instruction to simultaneously offer more challenge to over-prepared students and more support for under-prepared students.
- Host: Ke Zhang
Friday, March 10th, 2023
- Department Meeting
- Closed Department Meeting
- Time: 12:15 pm
- Place: VIRTUAL - Link will be sent later.
- Speaker: Mark Eriksson, UW-Madison
- Closed meeting to discuss personnel matters—pursuant to Section 19.85(1)(c) of the Wisconsin Open Meetings Law Closed to all but tenured faculty
- Host: Mark Eriksson
- Physics Department Colloquium
- Imprints of the Quantum Physics on the Universe
- Time: 3:30 pm
- Place: Chamberlin 2241
- Speaker: Jun'ichi Yokoyama, University of Tokyo
- Abstract: Our Universe is big, old, and full of structures. All of them are big mysteries in the classical Big Bang Cosmology. Inflationary cosmology, which postulates accelerated expansion in the early Universe, explain all of them. Inflation is driven by a quantum field, whose quantum fluctuations are stretched to fill the entire Universe. Their trace is observed in the Cosmic Microwave Background (CMB), and they also yield density fluctuations to form galaxies etc. Furthermore, where the fluctuations were large, they may have formed primordial black holes and may have been the origin of the black holes found by LIGO and Virgo. We have calculated not only the lowest-order perturbations, but also the loop effects, and found that the distribution of fluctuations must be highly Gaussian, and that the formation of primordial black holes would be inconsistent with the CMB.
- Host: Daniel Chung
Saturday, March 11th, 2023
- Academic Calendar
- Spring recess
- Abstract: *Note: actual end time may vary.* URL:
Sunday, March 12th, 2023
- Academic Calendar
- Spring recess
- Abstract: *Note: actual end time may vary.* URL: