Interaction of a hydrogen atom with an intense pulse of vacuum ultraviolet radiation

J. Phys. B 33, 1271 (2000)

Mariusz Gajda, Jacek Krzywinski, Lukasz Plucinski and Bernard Piraux

The free electron laser (FEL) which is currently under construction at the DESY laboratory should deliver a photon beam in the vacuum ultraviolet (VUV) range. Coherent radiation of the FEL will soon allow for testing of the matter-electromagnetic field interaction under very exotic conditions. In this paper we study the ionization of a hydrogen atom by the intense (about 1016 W cm-2 ) beam of photons with energies of 17 eV. We compare exact numerical results with predictions of the perturbation theory showing the limits of its applicability and discussing requirements for the FEL pulse parameters which are necessary for observation of non-perturbative phenomena.