Evolution of Temperature in the Ultracold Strongly-Correlated Plasmas

Abstract

We present a theoretical interpretation of the recently revealed features of temperature evolution in the ultracold plasma clouds released from a magneto-optical trap, namely: (a) its independence at the sufficiently large times on the initial plasma parameters and (b) the asymptotics close to t^{-1} instead of t^{-2}, expected for a rarefied ideal gas. It is shown that both these properties can be well explained by the model of virialization of the charged particle velocities in the regime of strong electron-ion correlations, while heating due to inelastic processes (e.g. three-body recombination) should be of secondary importance. These conclusions are confirmed also by the results of ab initio computer simulations.