Relativistic Laser Channeling into High-Density Plasmas

We experimentally studied relativistic laser propagation in preplasmas at the highest powers ever attempted-0.2 to 0.4 petawatt. We demonstrated a single conical-shaped plasma channel formation extending several hundred microns in length from the under dense to over dense plasmas, indicating whole-beam self-focused laser channeling into the high-density plasma. The channel cone was reproduced by a three dimensional particle-in-cell simulation. The confirmation of the relativistic laser channeling into high-density plasmas holds the promise of fast igniting a highly compressed fuel plasma core.