In this paper we present the analytical description of two processes
dealing with the skin-layer ponderomotive acceleration method of fast ion
generation by a short laser pulse: ion density rippling in the underdense
plasma region and generation of ion beams by trapped electromagnetic field
in plasma. Some numerical examples of hydrodynamic simulation illustrating
these processes are shown. The effect of using the laser pulse consisting
of different frequency components on the ion density rippling and on
phenomena connected with trapped electromagnetic field is analyzed.