Abstract :
The role of collisional absorption is shown to be important at the beginning of the interaction between a laser pulse and matter, i.e., a plasma, while later on collective absorption phenomena take place. The scope of this paper is to present first results about the long predicted AC-run-away effect, defined as a sudden transition from a collisional absorption regime to a collective one, in ideal circumstances: for an ultrashort laser pulse, i.e., subpicosecond pulses, and with a sharp plasma boundary, i.e., without a laser prepulse. For this purpose, we use a kinetic model based on the ballistic theory. The model is of relevance to laser-matter interaction including laser nuclear fusion or laser particle acceleration.
Keywords :
high-speed optical techniques; plasma boundary layers; plasma collision processes; plasma kinetic theory; plasma light propagation; AC-run-away effect; ballistic theory; collective absorption; collisional absorption; femtosecond laser-matter interaction; kinetic model; laser nuclear fusion; laser particle acceleration; plasma boundary; subpicosecond pulses; ultrashort laser pulse; Absorption; Fusion reactors; Kinetic theory; Laser fusion; Laser modes; Laser theory; Laser transitions; Linear particle accelerator; Optical pulses; Plasma accelerators; AC-run-away; ballistic collision model; electron collisions; laser-matter interaction;