Time-of-Flight Studies of Propagating Electron Plasma Waves in Tonks-Dattner Resonances

We describe here a series of time-of-flight experiments designed to investigate propagating electron plasma waves in a dc mercury-vapor discharge based upon the development of a phase-coherent nanosecond sine-wave burst. Signals of appreciable amplitude are observed to propagate with a finite velocity on the order of the electron thermal velocity and can be damped by increasing the electron neutral collision frequency. Multiple reflections of the signal are also detected.