The physics of collisionless absorption and particle acceleration by superintense laser beams

摘要

The status of present understanding of collisionless absorption of intense laser pulses out of linear resonance is discussed in Sec. 1. In Sec. 2 skin layer absorption is modelled in a test particle picture and it is shown that the energy gained by a single particle depends strongly on the injection phase relative to the laser field and that electron reflection is not localized at the target boundary. To provide for adequate absorption an energetic component must be present. The main achievement of this paper is contained in Sec. 3. We show that most of collective (collisionless) absorption is by anharmonic resonance of electron bunches in their own space charge field. In Sec. 4 basic considerations on electron acceleration by laser beams in vacuum are outlined and a summary of the main achievements by wake field acceleration in tenuous plasmas is presented.