Related Experiment Video
Updated: Jan 5, 2026

Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry
Published on: August 1, 2017
Acoustic self-oscillation in a spherical microwave plasma
Seth Pree1, Seth Putterman1, John P Koulakis1
1Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, California 90095, USA.
Abstract:
We present a method of sound amplification and self-oscillation in high pressure partially ionized gas. Continuous microwaves incident on partially ionized gas may sustain and amplify an acoustic field if increased ionization during the sound field's adiabatic compression enhances rf power absorption. Amplifying sound in this way enables the generation of high amplitude sound in a cavity containing partially ionized gas without mechanical driving or precise knowledge of its resonance frequency. This method of amplification may open opportunities within thermoacoustics such as using three-dimensional geometries and volumetric gain mechanisms.
Related Concept Videos
Standing Waves in a Cavity
Oscillations In An LC Circuit
Atomic Nuclei: Nuclear Relaxation Processes
Oscillations about an Equilibrium Position
Electromagnetic Waves
Damped Oscillations
Although friction and other non-conservative...

