Electron Temperature of Ultracold Plasmas
  We study the evolution of ultracold plasmas by measuring the electron temperature. Shortly after plasma formation, competition between heating and cooling mechanisms drives the electron temperature to a value within a narrow range regardless of the initial energy imparted to the electrons. In agreement with theory predictions, plasmas exhibit values of the Coulomb coupling parameter $\Gamma$ less than 1. 
J. L. Roberts, C. F. Fertig, M. L. Lim and S. L. Rolston