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

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 Tc and electron temperature T0 on the discharge axis is determined by radial optical thickness τR of the plasma column: Tc ≈ T0 at τR ≈ 1, Tc< T0 at τR< 1, and Tc >T0 at τR > 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.