Temperature and mean axial momentum vs. laser intensity of electrons released from O${}_2$ by an 800 nm ultrashort pulsed laser

Abstract

A semi-empirical model is presented for the thermalized temperature $T$ and mean momentum in the direction of laser propagation <$p_{fz}$> of electrons released from O${}_2$ after the passage of a focused 800 nm ultrashort pulsed laser pulse vs. peak laser intensity $I_0$ to provide initial conditions for plasma electrodynamic simulations. For this, theoretical kinetic energy spectra based on the most probable ionization path of a nonadiabatic Strong Field Approximation (SFA) are fit to experimental spectra by two adjustable parameters assumed to represent the effects of electron recombination with or rescatter off of its parent ion during the optical cycle subsequent to ionization. These are effects not treated by the original SFA. The classical kinematics of elastic rescatter and the Lorentz force, then, are used to estimate <$p_{fz}$>.

15 pages, 11 figures/subfigures. Journal submission pending