Investigations on the fundamental longitudinal acoustic resonance of high pressure discharge lamps

Abstract
Cylindrical high pressure mercury discharge lamps were operated on a sinusoidal supply voltage at frequencies in the vicinity of their fundamental longitudinal acoustic resonance band. The sound spectrum emitted from the lamp allows the detection of pressure waves in the lamp gas volume. With this method it is shown that there are acoustic resonances which are not combined with visual arc instabilities. In this case the influence of the acoustic resonance on arc and wall temperature profiles was measured. The experimental results can be explained by an additional axial heat flow caused by the acoustic pressure waves.