Ponderomotive acceleration of electrons at the focus of high intensity lasers

Ponderomotive-force driven acceleration of an electron at the focus of a high-intensity short-pulse laser is considered using a model that accounts for its averaged drift motion but neglects its fast-varying quiver motion. It is shown that at relativistic laser intensities the ponderomotive acceleration mechanism can be significant even for an electron initially at rest. The latter can easily be driven out of the interaction region by the radial component of the ponderomotive force. For intensities above 10(19) W mu m(2)/cm(2), energy gains in the range of MeV can be realized.