Recombination properties of Rydberg nonequilibrium plasma created by dye laser

Abstract

Ultracold Rydberg plasma formed by a dye laser has been studied theoretically. Recombination properties in the presence of three-body collisions in hydrogen-like plasma have been investigated. We have shown that the existing calculation models for three-body recombination (Thomson model, diffusion approximation, and modified diffusion approximation) work only in the high-electron-temperature region—more than or equal to 1 eV. When the electron temperature is substantially less 1 eV, we have found the strong dependence of process probability on the energy of free particle. As a result, there is a drastic slowdown recombination in the region, where the three-body recombination dominates. Another reason for this slowdown of the recombination deals with the increment nonideality parameter. Effect of slowdown of recombination with free-body collisions can be reduced to the situation when the thermal equilibrium is set earlier than the ionization equilibrium, and, hence, the formation of metastable structure is possible in the plasma. Also this effect can cause the inverse population on Rydberg levels.