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Events During the Week of April 7th through April 14th, 2024

Monday, April 8th, 2024

Plasma Physics (Physics/ECE/NE 922) Seminar
“Controlling plasma-material interactions with real-time powdered material injection”
Time: 12:00 pm - 1:15 pm
Place: 1227 Engineering Dr
Speaker: Florian Effenberg, PPPL
Abstract: In the DIII-D tokamak, coatings up to 10 nm thick were grown on plasma-facing components (PFCs) at 1 nm/s using boron (B) and silicon (Si) injections in both powder and pellet forms during L-mode and H-mode discharges. Utilizing the impurity powder dropper (IPD) and the impurity granule injector (IGI), materials were injected at rates of 1-200 mg/s, with varying sizes and speeds, enhancing wall conditions akin to glow discharge boronization by reducing impurity influxes and significantly increasing the density-to-gas fueling ratio. Post-mortem analysis confirmed the formation of B-C layers with average surface composition B:C∼1. Si pellet injection at a rate of 1-15 mg/s yielded Si-rich layers on the divertor tiles of at least 1 nm in thickness. The in-situ growth of thin films in real-time demonstrates the capability of surface material replenishment during long-pulse plasma operation or steady-state devices without ramp-down of the magnetic fields.

Concurrently, B and BN powder injections into the SAS-VW divertor demonstrated significant effects on heat flux and W erosion control without adversely affecting H-mode performance. Specifically, B injections at rates up to 25 mg/s resulted in a notable decrease in W deposition. In contrast, BN injections led to substantial X-point radiation, prominently reducing heat fluxes and W erosion through detachment. These outcomes underline the efficacy of powder injection techniques in managing plasma-material interactions, particularly in high-Z environments, highlighting their potential in next-step long-pulse devices.
Host: Prof. Oliver Schmitz and Prof. Carl Sovinec
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Tuesday, April 9th, 2024

No events scheduled

Wednesday, April 10th, 2024

No events scheduled

Thursday, April 11th, 2024

NPAC (Nuclear/Particle/Astro/Cosmo) Forum
Mysteries of the High-Energy Sky
Time: 9:00 am - 10:00 am
Place: 5280 Chamberlin Hall and
Speaker: Dan Hooper, Fermilab
Abstract: It has been more than a century since the discovery of cosmic rays, and yet there remains much that we do not know about these mysterious particles. In particular, it is an open question as to where many of the cosmic rays come from and how they are accelerated to such incredible energies. The resolution to these puzzles will require not only measurements of the cosmic rays themselves, but also information provided by gamma-ray, X-ray, optical, infrared, and radio telescopes, gravitational wave detectors, and high-energy neutrino telescopes. It will be through this program of multi-messenger astronomy that we will finally be able to identify the sources of the cosmic rays and cosmic neutrinos, and begin to understand the physics behind these naturally occurring engines of high-energy particle acceleration. This observational program will also provide exciting opportunities for the field of particle physics, allowing us to test a variety of new physics scenarios, to search for the particle nature of dark matter, and to further probe the physics of neutrino oscillations.
Host: Francis Halzen
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Astronomy Colloquium
Water under X-ray Vision - A Molecular Look at Life’s Mysterious Elixir
Time: 3:30 pm - 4:30 pm
Place: 4421 Sterling Hall
Speaker: Uwe Bergmann, UW-Madison
Abstract: Every life form on earth requires liquid water to function and when we look for life in space, we often look for water signatures. Yet, we still don’t know precisely how the water molecules are arranged in the liquid. We also don’t know how exactly plants and algae split the water molecules to form molecular oxygen during photosynthesis. This over three-billion-year-old process has created essentially all the oxygen in our atmosphere and therefore enabled the evolution of all lifeforms relying on respiration. Understanding this mechanism can also help us to create new fuels based on sunlight.

Powerful new synchrotron X-ray sources have enabled detailed atomic level investigation of the structure of water and the photosynthetic water splitting. We will first describe these amazing X-ray sources and the various techniques that have been used to carry out these studies. We will then review our current understanding and the most recent progress of solving these two compelling mysteries, which have critically shaped the existence of life on earth.
Host: Ke Zhang
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Friday, April 12th, 2024

Climate & Diversity
Climate and Diversity Committee End of Year Town Hall and Mixer
Time: 2:30 pm - 3:30 pm
Place: Chamberlin 2241
Speaker: , Climate and Diversity Committee
Abstract: The Climate and Diversity Committee is hosting an end of year Town Hall Mixer and we hope to see you there! On Friday, April 12th from 2:30-3:30pm in Chamberlin 2241. Come before the seminar for refreshments, a review of the committee’s work this year, and an opportunity to share feedback for the committee. Everyone is welcome – so we hope to see you there!
Host: Rachel Zizmann
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Physics Department Colloquium
Mitigating climate and air pollution from the electricity and transportation sectors in the United States
Time: 3:30 pm - 5:00 pm
Place: Chamberlin 2241
Speaker: Inês Azevedo, Stanford University
Abstract: In this talk, I will cover a few recent papers and projects that focus on the measurement of emissions and the costs, benefits, and opportunities associated with a transition to sustainable, deeply decarbonized,, and equitable energy systems is needed in the United States. For example, in [1], we show that with an increasing interconnected system that encompasses variable energy sources and complex markets, the emissions embedded in electricity generation and consumption are becoming more difficult to estimate. Using flow tracing and consumption-based accounting, we have characterized the health damages from exposure to PM2.5 from electricity imports and find that that 8% of our estimated premature deaths from electricity consumption in the United States are due to electricity imports; In [2] we assess the consequences of vehicle electrification across the country as a function of where vehicles are charged, and which types of plants are meeting that electricity demand, and in [3] we present a data-driven, realistic model of charging demand that captures the diverse charging behaviors of future adopters in the US Western Interconnection. We find that peak net electricity demand increases by up to 25% with forecast adoption and by 50% in a stress test with full electrification; In ongoing work, we develop tools and analysis that identify the most cost-effective strategies for retirement and replacements of existing electricity generation capacity, which can help guide state and federal decision-makers deep decarbonization plans.
Host: Uwe Bergmann
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