A STATISTICAL INTERPRETATION FOR ABOVE THRESHOLD IONIZATION USING A SEMICLASSICAL LASER PULSE MODEL

Abstract

A semiclassical model for highly intense laser pulses is introduced. Such pulses are often used to study Above Threshold Ionization which is a non-perturbative mult/photon process. Pertubation theory as well as other approximate techniques had failed to provide agreement with experiment and had constantly pointed to the Importance of the modeling of the laser pulse Itself. The model presented here photon which has a finite makes us dimension. of a Th sem\classical pulse under consideration can be divided into elementary cells each having the same transverse slze of the photon, each cell is associated with a characteristic interaction length, that shows a unique dependence on the intensity. The relation between the characteristic length and the intensity Is derived from comparisons with experiments. It is shown that the characteristic length varles as the intensity to the power 0.75, independent of the experimental setup or the gas under consideration. Along the Interaction length, it is shown than an atom absorbos a number