Asymmetric High-Energy Ion Emission from Argon Clusters in Intense Laser Fields

Clusters of $2\times {10}^3$ to $4\times {10}^4$ Ar atoms are Coulomb exploded in intense (up to $8\times {10}^{15}\mathrm{W}{\mathrm{cm}}^{-2\mathrm{}}$) laser fields. The dependence of multiply charged argon ion energies on the polarization state of light is probed. A directional asymmetry in the ion-explosion energies is observed for the highest charge states. The ion-energy distribution consists of a low-energy isotropic component, and a high-energy anisotropic one. The results are discussed in terms of an asymmetric Coulomb-explosion scenario.