Published online by Cambridge University Press: 09 March 2009
High-intensity laser beams propagating in a plasma become focused because the index of refraction depends on the relativistic mass of the electron and therefore is a function of the electric field strength through the electron velocity. Around the focus the laser field has such a high density of energy that electrons and ions are emitted owing to the nonlinear force arising from this field. The equations of motion for the electrons and the ions and the Maxwellian equations for the laser and plasma fields are solved under certain approximations. We calculate the maximal energy and the angular distribution of the emitted ions and compare the results with experimental data.