Probe-triggered audiofrequency plasma oscillations

Coherent sinusoidal oscillations have been observed in a magnetized dc gas discharge in neon. The oscillations have frequencies from 70 Hz to 7 kHz and are triggered by a small dc bias on a wire probe immersed in the discharge. The oscillation period is proportional to the cube of the applied magnetic field and inversely proportional to the cube root of the discharge current.