Excitation of acoustic instabilities in discharge lamps with pulsed supply voltage

Abstract

A problem associated with high frequency operation of high pressure discharge lamps is the occurrence of acoustic resonances of the gas volume inside the lamp in certain frequency regions. These resonances usually cause arc instabilities which make convenient lamp operation impossible. In this paper an investigation is made of the occurrence of acoustic resonances and arc instabilities as a function of the modulation depth of the lamp power. A critical value of this modulation depth, below which no arc instabilities occur in the power frequency range from 0 to 50 kHz, has been determined for different commercial lamp types.