Self-field-limiting current density in field-photoemission of intense short relativistic electron beams

Electrons of an intense short pulse produced by laser irradiation are submitted, just after their photoemission, to a very strong RF field. The acceleration is so strong that relativistic acceleration and retardation effects have to be taken into account. The self-field-limiting current density is theoretically discussed, as a function of beam parameters and RF field intensity. The relativistic Child-Langmuir current density, i.e. the corresponding steady state space-charge limit is compared to the self-field-limiting current density. (G.P.) 2 refs.; 4 figs