Graduate Program Events |
Events During the Week of June 4th through June 11th, 2023
Monday, June 5th, 2023
- Thesis Defense
- The Magellanic Corona and its Role in the Evolution of the Magellanic Stream
- Time: 10:00 am - 12:00 pm
- Place: 2241 Chamberlin or
- Speaker: Scott Lucchini, Department of Physics Graduate Student
- Abstract: The Magellanic System is the perfect opportunity to explore many aspects of astrophysics right on our Galaxy’s doorstep. The Large and Small Magellanic Clouds (LMC, SMC) are interacting with each other and with the Milky Way to form the Magellanic Stream, a multiphase gaseous tail of intertwined filaments trailing behind the Clouds. Here we can study galactic dynamics, gas dynamics, turbulent processes, gas cooling and mixing, metal transport, and more. However, there are two outstanding mysteries as to how the Magellanic System came to be -- its large amount of ionized gas, and the high mass of the LMC. To solve both these discrepancies simultaneously, we introduced the Magellanic Corona. This warm, ionized circumgalactic medium should surround the LMC as it interacts with the SMC and the Milky Way. Throughout my thesis work, I have used high-resolution numerical simulations of the formation of the Magellanic Stream to test this new model including the Magellanic Corona. We can account for both the neutral and ionized components of the Stream while also reproducing the present-day positions and velocities of the LMC and the SMC. We have also found a new family of orbital histories for the Clouds that result in the neutral Stream being significantly closer than previous models predicted. The Magellanic Corona seems to be the key to the formation of the Magellanic Stream and has many implications throughout galaxy evolution.
Tuesday, June 6th, 2023
- Will gamma rays break superconducting quantum computers? And can surface encapsulation improve the performance of individual quantum bits?
- Time: 9:00 am - 11:00 am
- Place: 4274 Chamberlin
- Speaker: Sohair Abdullah, Physics Graduate Student
- Host: Robert McDermott
Wednesday, June 7th, 2023
- Final Thesis Defense
- Lundquist Number Scaling in the MST Reversed-Field Pinch
- Time: 10:00 am - 12:00 pm
- Place: B343 Sterling or
- Speaker: Steph Kubala, Department of Physics Graduate Student
- Abstract: Nonlinear MHD fluctuations appear in both natural and magnetic confinement settings, such as the solar wind, self-organization dynamics in the RFP and spheromak, and current disruptions in tokamak plasmas. In this thesis, parameter scaling experiments oriented toward nonlinear MHD dynamics in RFP plasmas are presented. Experimental data have been gathered spanning a wide range of parameter space characterized by Lundquist number, S ∼ 104 −107, and density where is the empirical density limit. A new programmable power supply allows low-current, low-S operation, which overlaps with parameters available in numerical modeling. Experimental S scalings of magnetic fluctuation amplitude agree well with those from the nonlinear MHD codes DEBS and NIMROD. A transition from quasi-continuous activity to bursty relaxation having discrete sawtooth events is observed in going from low to high S, with a threshold at around S ∼ 105. The spectral properties of the magnetic fluctuations change at this transition, including a reduction in fluctuation phase velocity that suggests plasma flow and/or flow profile changes. Momentum transport and flattening of the flow profile are known features associated with sawtooth relaxation in RFP plasmas.
Thursday, June 8th, 2023
- No events scheduled
Friday, June 9th, 2023
- No events scheduled