Energy and Time-resolved Measurements of High Energy Electrons Emitted from a Laser-Plasma Interaction

Irradiating materials with high energy, short pulse lasers create rapidly evolving plasma states. Deconvolving the physical mechanisms responsible for the plasma evolution necessitates time-resolved diagnostic measurements. In the high energy density regime, electrons dominate energy transport within the plasma, making them an obvious candidate for study. We recently demonstrated a novel technique for observing time-resolved energy spectra of hot electrons escaping from the target. Exploiting this technique, we measured high energy ($\sim $MeV) electrons accelerated from a solid foil ($\sim $10 micron) irradiated by a high intensity ($>$10$^{19}$ W/cm$^{2})$, short pulse ($\sim $100fs) laser. Preliminary analysis shows hot electron lifetimes on the order of 10 ps. Future experiments will combine the above technique with a time-resolved measurement of K-alpha emission, which gives insight into the refluxing electrons.