A Positron Plasma in the Laboratory.

We have developed a method to accumulate and store fast positrons from a sup (22) Na radioactive source in an electrostatic trap using a tungsten moderator and inelastic collisions with nitrogen molecules. The resulting positron gas is found to cool to room temperature, and to fulfill the criteria for a single- component, positron plasma. The cooling and confinement processes are discussed as well as the potential applications of this many-positron system.