Tue28Apr20204:00 pmZoom Meeting See Below.
Colloquium: Acoustic Plasma Trapping and Plasma Thermoacoustics
Department of Physics and Astronomy
University of California — Los Angeles
Acoustic Plasma Trapping and Plasma Thermoacoustics
An oven's worth of microwaves can be used to both make a few thousand Kelvin plasma and cause that plasma to generate sound. Such a system can be used as a tweeter, but the luminous plasma subjected to its own sound field raises more interesting opportunities in both nonlinear acoustics and thermoacoustics. For example, how can the sound field established by modulating the microwave power lighting up a ping-pong ball sized bulb containing 30 mg of sulfur trap the resulting 3000+ K plasma in the center of a spherical cavity? Continuous wave (CW) microwaves may also be used to generate sound via the Sondhauss effect in a Helmholtz resonator. I will end by presenting an unconventional, 3D thermoacoustic gain mechanism based on the variation in the plasma’s conductivity due to the sound’s adiabatic compression. If realized, 3D plasma thermoacoustics may help addressing questions about Cepheid variable stars.
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