Ion expansion characteristics from a KrF-laser-produced plasma

Two groups of ions are observed in an aluminum plasma produced by focusing a Raman-compressed KrF-laser beam (268 nm) on thick planar targets in the intensity range 5×${10}^{11}$–${10}^{13}$ W/${\mathrm{cm}}^2$. The angular distribution, velocity distribution, energy partition between the two groups, and scaling of the ion velocities with laser intensity are presented. The role of lateral energy transport in generating the two groups of ions is discussed.