Increased Hot-Electron Production at Quarter-Critical Density in Long-Scale-Length Laser-Plasma Interactions

Abstract
Hot-electron fractions measured in Nd-laser-plasma interactions at 1014 W/cm2 increase from <0.02% to 0.3% as the plasma scale length at quarter-critical density (nc4) is systematically increased from 140 to 320 μm. Correlated x-ray and 3ω2 emissions indicate that the hot electrons are produced by an nc4 instability.