A simple model is proposed to study the field generated
by a 3D plasma layer. The model neglects electron–electron
interactions in the same way as occurs in the well known
moving mirror models. However, the present model considers
the radiation emitted by the moving electrons in a more
precise way than in the mirror models, and allows the study
of underdense or near critical plasmas. Results, including
the transverse intensity profile of the driving field,
are presented that show the possibility of generating trains
of attosecond pulses.