Applied Physics Seminar

Abstract:

With the discovery of exo-planets, astrophysicists have realized that planetary diversity is not has abundant as previously thought. While the classification covers Jovian worlds all the way down to mini-terran bodies, planetary characteristics in each category can be very subtle. In fact, astrophysicists need to go beyond observations to understand the formation and subsequent evolution of these planets. They need a precise knowledge of material properties deep inside the planet, from the mantle to its core.

Observable bodies usually have gargantuan sizes and their gravity compresses materials well above one megabar. In this regime, the ions are strongly coupled (100 times solid density), freeing electrons from their orbitals. The electrons, now close enough to be fully quantum degenerate, have acquired large temperatures (~10,000K) during the compression process. While this matter, labeled as warm dense, is key to capturing planetary evolution, its macroscopic properties, like heat conduction or viscosity, are virtually unknown.
In this talk, we show how pulsed-power generators might bring new opportunities in reaching regimes relevant to the study of planetary interiors. In comparison to high power lasers, pulsed-power generators can produce samples with larger sizes and on longer compression times. In these regimes, the quantum properties of matter are transferred to macroscopic scales via collisional processes. The resulting material can be probed using high brilliance x-ray light sources. The measured bulk properties can be benchmarked against new quantum mechanical models, going beyond density functional theory and molecular dynamics. Only then will these models capture more accurately the macroscopic quantum properties of matter under extreme pressure.

More about the Speaker:

Starting his career in magnetic confinement fusion at UCLA, Prof. Gourdain moved to Cornell University after his Ph.D. to study matter under extreme conditions on the Cornell Beam Research Accelerator. Prof. Gourdain is now an Assistant Professor of Physics and Astronomy at the University of Rochester. At UCLA, Prof. Gourdain built and operated the Electric Tokamak. There he studied the stabilization of runaway confinement using fast ion pumping from ion cyclotron resonance. He studied the impact of Hall effect on high energy density plasma jets at Cornell University.