Modeling of a Focused Laser Field and Acceleration of Electrons in the Presence of a Static Magnetic Field Collinear to the Magnetic Field of the Laser Light

Acceleration of electrons by an intense focused laser field combined with a static magnetic field is considered. A geometry is chosen in which the static magnetic field is parallel to the alternating magnetic field in the laser wave. In contrast with earlier proposed models, the focused laser field is described by a superposition of plane waves. This approach is both realistic and sufficiently rigorous. It is shown that the electron energy can increase several times after a single passage through the focus. The conditions of applicability of this result are obtained. One of these conditions, unknown earlier, predicts that insufficiently short focusing is not favorable for efficient acceleration. Optimal parameters of the laser focus are found.