Accuracy of the averaged description of the motion of charged particles in high-frequency fields

Abstract

The accuracy of the averaged ponderomotive description of the motion of charged particles in smoothly inhomogeneous high-frequency electromagnetic fields in the nonrelativistic approximation is considered. Average equations are derived within the Hamilton perturbation theory using the technique of canonical transformations. Corrections to the ponderomotive potential, including inertial ones, i.e., those depending on the drift momentum, are found. It is shown that the change in the particle energy after the interaction with the field is exponentially small in the adiabaticity parameter gv/ωL.