TRANSMISSION THROUGH HIGHLY OVERDENSE PLASMA SLABS WITH A SUBPICOSECOND RELATIVISTIC LASER-PULSE

Transmission of a subpicosecond relativistic laser pulse is observed t hrough solid foils and preformed overcritical plasmas. Transmission ra tes near 10% for densities above 10 x n(c) are measured. A strong thre shold in intensity is found in order to observe this effect, The exper imental results as well as preliminary particle-in-cell simulations su ggest that for thin solid foils the observed transmission is explicabl e by rapid heating and expansion to transmissive conditions during the pulse. Self-induced transparency and hole boring processes apply to t hicker preformed plasmas. These results have important implications in fast ignition for inertial confinement fusion.