Single and Multiple Electron Dynamics in the Strong Field Limit

High precision photoelectron energy and angular distributions in helium and neon atoms for a broad intensity range reflect the change in the continuum dynamics that occurs as the ionization process evolves into the pure tunneling regime. Elastic rescattering of the laser-driven free electron from its parent ion core leaves a distinct signature on the spectra, providing a direct quantitative test of the various theories of strong field multiphoton ionization. We show that it takes a relatively complete semi-classical rescattering model to accurately reproduce the observed photoelectron distributions. However, the calculated inelastic rescattering rate fails to reproduce the measured nonsequential double ionization yields.