Abstract

The development of high-power femtosecond lasers has made possible experiments on laserplasma interactions in the relativistic regime. Experiments at this intensity level are of great interest because of a number of applications such as fast ignition of laser fusion targets, particle acceleration, hard x-ray and high order harmonic generation (HOHG), etc. During the laser-solid interaction at such an intensity the target is highly ionized by the leading edge of the pump pulse, and a reflecting layer of supercritical plasma is formed. Neglecting the details of the electron density distribution, the motion of the electrons in the field of the incident electromagnetic wave can be considered as an “oscillating mirror”. At high intensities this mirror can be distorted by plasma instabilities and surface deformations induced by ponderomotive forces. Unfortunately, different processes contributing to the mirror distortions are generally difficult to identify. These instabilities and deformations strongly depend on the plasma scale length, the parameter which is difficult to control in experiments.

© 2002 Optical Society of America