Recombination fluorescence in ultracold plasmas

The expansion dynamics of ultracold neutral plasmas are determined by electron physics. Three-body recombination and electron-Rydberg scattering heat the plasma electrons at early times and drive the expansion. The details of these processes are well understood in weakly-coupled plasmas. However, these processes may proceed differently in strongly-coupled neutral systems. We present a study of recombination fluorescence in ultracold plasmas. At low densities, we find good agreement between theory and experiment. At higher densities, theory and experiment diverge.