Energy distributions of electrons emitted by a biased laser-produced plasma at 1013 W cm−2

In this paper, we present the electron bunches extracted from a dense plasma produced by the interaction of a ns laser at an intensity of 1013 W cm−2 with a solid target, when this plasma expands in an electric field. The plasma expansion dynamics measured in the previous works [M. Comet et al., J. Appl. Phys. 119, 013301 (2016)] is used to determine the electron charge density profile at different instants after the laser shot. When applying the electric field, a few 1013 electrons are extracted with continuous energy distributions. Particle-In-Cell simulations are run to understand the extraction process and reproduce the measured energy distributions, with the electron charge density profiles used as inputs. These simulations show that the electron extraction proceeds from the plasma front edge throughout the plasma expansion.