Radiation friction vs ponderomotive effect
  The concept of ponderomotive potential is upgraded to a regime in which radiation friction becomes dominant. The radiation friction manifests itself in novel features of long-term capturing of the particles released at the focus and impenetrability of the focus from the exterior. We apply time scales separation to the Landau-Lifshitz equation splitting the particle motion into quivering and slow drift of a guiding center. The drift equation is deduced by averaging over fast motion. 
A.M. Fedotov, N.V. Elkina, E.G. Gelfer, N.B. Narozhny and H. Ruhl
physics.plasm-ph physics.comp-ph physics.optics