Scattering of relativistic electrons by a focused laser pulse

The problem of the motion of a classical relativistic electron in a focused high-intensity laser pulse is solved. A new three-dimensional model of the electromagnetic field, which is an exact solution of Maxwell's equations, is proposed to describe a stationary laser beam. An extension of the model is proposed. This extension describes a laser pulse of finite duration and is an approximate solution of Maxwell's equations. The equations for the av erage motion of an electron in the field of a laser pulse, described by our model, are derived assuming weak spatial and temporal nonuniformities of t he field. It is shown that, to a first approximation in the parameters of t he nonuniformities, the average (ponderomotive) force acting on a particle is described by the gradient of the ponderomotive potential, but it loses i ts potential character even in second order. It is found that the three-dim ensional ponderomotive potential is asymmetric. The trajectories of relativ istic electrons moving in a laser field are obtained and the cross sections for scattering of electrons by a stationary laser beam are calculated. It is shown that reflection of electrons from the laser pulse and the surfing effect are present in the model studied. It is found that for certain impac t parameters of the incident electrons the asymmetic ponderomotive potentia l can manifest itself effectively as an attractive potential. It is also sh own that even in the case of a symmetric potential the scattering cross sec tion contains singularities, known as rainbow scattering. The results are a pplicable for fields characterized by large (compared to 1) values of the d imensionless parameter eta(2) = e(2)[E-2]/m(2)omega(2) and arbitrary electr on energies. (C) 2000 MAIK "Nauka/Interperiodica".