Hot Electron Generation Using High Intensity Laser Pulses on Machined Conical Targets*

The relative number of the fast electrons has been experimentally measured for a high intensity (4x10$^{20 }$W/cm$^{2})$ laser pulse interaction with in situ machined conical aluminum targets. It is shown that the number of electrons and the plasma x-ray signal strongly depends on the cone depth. The cone was laser machined immediately before the 30 TW pulse arrival possibly allowing for a faster, cheaper alternative to traditional conical targets. Particle-in-cell simulations performed for the experimental conditions will be presented. Laser machined conical targets provide a higher laser conversion efficiency into hot electrons.