Events at Physics
Events on Monday, March 4th, 2019
- Special Noon Talk 3/4/19
- Star Formation, etc
- Time: 12:00 pm
- Place: 4421 Sterling Hall
- Speaker: Nia Imara, Harvard CfA
- Abstract: Stars are of fundamental importance to astronomy, and how they form and shape their environments influence everything from exoplanet studies to cosmology. In this talk, I will discuss recent ALMA observations of dwarf galaxies—excellent astrophysical laboratories for exploring star formation in the early Universe—and I will consider some future prospects for advancing our knowledge in this exciting field. As a bonus, I will present a novel idea for detecting planets bound to x-ray binaries, proposing that the x-ray light curves of such systems be inspected for signatures of transiting planets.
- Host: Sebastian Heinz, Astronomy Chair
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Ion-scale turbulence in the presence of a large magnetic island
- Time: 12:05 pm
- Place: 2241 Chamberlin Hall
- Speaker: Lucas Morton, UW-Madison
- Abstract: Understanding the effect of magnetic field geometry on turbulence is important for both tokamaks and stellarators. The introduction of a magnetic island to a toroidal plasma might influence turbulence in several ways: directly through geometric effects or indirectly through modifications to gradients that drive turbulence or flows that suppress turbulence. In an experiment on DIII-D tokamak, we studied the response of ion-gyro-radius scale density fluctuations using the Beam Emission Spectroscopy (BES) diagnostic. Our results confirm qualitative predictions of prior turbulence simulations, especially the reduction of turbulent fluctuations at the center of the island. This motivates dedicated simulations to understand the relative contribution of the various mechanisms by which magnetic geometry impacts turbulence in this situation.