We know that as lightning heats up the air it creates a pressure pulse which we all recognize as thunder. If we modulate the frequency of the lightning to an audible range the result is a plasma that "sings" at the frequencies we supply it with....a Plasma Speaker!
We study several plasma speakers of different sizes, from a small one that goes with us to outreach events, to a 3ft tall speaker which creates up to 1 ft. plasma arcs.
Research led by high school and undergraduate interns has shed light into the physics of the speaker, including its acoustic properties, as well as the spectral properties of the plasma. Some of the findings include the verification of the speakers acoustic isotropy and the favorable comparison of the plasma speaker's fidelity as compared to a standard mechanical loudspeaker.