Research On Plasmas Produced By Ultrashort Laser Pulses

Ultrashort ultraintense laser plasma is a new emerging frontier of physics in recent years. It has extensive prospects in laser evaporation deposition, laser propulsion, new type particle accelerator, intense ultrafast X-ray source, fast ignition with inertial confinement fusion ( IFC ) etc. Therefore, it is necessary to research the plasma produced by intense laser irradiation on a solid target.In this thesis, we set forth the properties, generation and interaction of laser plasmas. A simplified model which considers the partially ionized plasma as hydrogen-like ions is presented. Classical electrodynamics theory is employed to study the action of ponderomotive force on bound electron and the effect of ponderomotive force on the generation of laser plasmas. A relation between generation of laser plasma and laser wave train length is obtained. Specifically we analyse the relation between pulse width and plasma generation under the action of a Q-switched or a mode-locked laser output.