High-Temperature Plasmas Produced by Laser Beam Irradiation of Single Solid Particles

The focused 20-MW giant pulse beam of a Q-spoiled ruby laser has been used to form a high-temperature, high-density plasma from a single 10- to 20-μ-diam solid particle of lithium hydride suspended by a set of ac electric fields in a vacuum environment. Charge collection measurements show that total ionization of the 1015 atoms in the lithium hydride particle is achieved in the plasma produced. Time-of-flight studies of the expanding plasma yield plasma energies of more than 100 eV. Measurements have been carried out which show that the mass and energy density of the expanding plasma are isotropically distributed in space. The results obtained are in good agreement with a simple model of the plasma formation and expansion. Further studies of these laser-irradiated, single particle plasmas are in progress and include measurements of the lifetime of the plasma in magnetic confinement fields.