HIGH-PRESSURE SODIUM LAMP.

Abstract

The discharge in a high-pressure sodium lamp can be described on the basis of a model consisting of the continuity equations for the particle densities, the energy-balance equation, and the equation of state for the gas. Because of the high pressure it is sufficient for most calculations to assume that the gas temperature and electron temperature are identical. Most problems are encountered in calculating the radiative energy transport. The buffer gas - mercury and xenon - added to the discharge to control the thermal and electrical properties of the plasma is shown to have some influence on the spectral distribution of the emitted radiation. The insight into the operation of a high-pressure sodium lamp, obtained from experiment and theory, can be very useful in designing high-pressure sodium lamps for which the lamp voltage, the wall temperature and the power dissipation have been specified.