抄録
Electron motions in laser fields are analyzed in cases when the laser field is non-relativistic and when it is relativistic. The typical eight-figure motion of an electron is obtained in weak laser field plane-polarized, while no such figure motion in circular-polarized case. Starting from the Lagrangian for an electron in a plane-polarized electromagnetic wave, constants of motions and the electron orbits are analytically obtained. It is demonstrated that the electron drifts with a constant velocity in the direction of wave propagation, and that the eight-figure motion is seen in the frame moving with the drift motion. In the case of the circular-polarize wave, the electron orbit is a spiral having the drift velocity same as does the plane-polarization.
