title: Variational analysis of self-focusing of intense ultrashort pulses in gases.
abstract: By using perturbation theory we derive an expression for the electrical field of a Gaussian laser beam propagating in a gas medium. This expression is used as a trial solution in a variational method to get quasi-analytical solutions for the width, intensity, and self-focusing distance. The approximation gives a better agreement with results of numerical simulations for a broad range of values of the input power than previous analytical results available in the literature. The results apply in the case of ultrashort pulses too.
authors.affiliation: Max-Planck-Institut für Physik Komplexer Systeme, Nöthnitzer Strasse 38, D-01187 Dresden, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Arévalo
authors.forename: A
authors.initials: A
authors.lastname: Becker