The Planck’s character and temperature of visible radiation of a pulse-periodic discharge in cesium vapor

Abstract

The radiation spectrum of pulse-periodic discharge in cesium vapor has been simulated in the framework of a two-temperature multifluid radiative gasdynamic model. It is established that, at a broad range of vapor pressures, the discharge spectrum exhibits a Planck character in a significant part of the visible spectral interval, which accounts for the high quality of color rendering in the discharge radiation. The relation between color temperature T_c and electron temperature T₀ on the discharge axis is determined by radial optical thickness τ_R of the plasma column: T_c ≈ T₀ at τ_R ≈ 1, T_c< T₀ at τ_R< 1, and T_c >T₀ at τ_R > 1. As the vapor pressure increases from 83 to 1087 Torr, color rendering index Ra of the discharge radiation changes from 95 to 98 and the color temperature grows from 3600 to 5200 K.