IONIZATION OF HE BY ULTRASTRONG SINGLE-CYCLE PULSES

Recently, the progress of experimental techniques has allowed the real ization of less-than-a-cycle pulses. Though these pulses are as yet to o weak to ionize atoms from the ground state, the rapid progress in ex perimental methods warrants the investigation of possibilities opened up by these new achievements. In this paper we use the quasiclassical Fermi molecular-dynamics method to study the dynamics of ionization an d the electron correlations of initially ground-state He atoms in sing le-cycle infrared pulses. An interpretation is also made in terms of a quasistatic ionization model.