Harmonics spontaneous emission due to electron motion in laser standing wave

The dynamics and harmonics emission spectra due to electron motion in laser standing wave have been investigated considering a single electron model. The motion status of electron and harmonics radiation spectra are numerically analyzed. The electron with incident position at node and incident direction vertical to magnetic field oscillates rapidly under Lorentz force. The spectrum of radiation is redshifted for backward radiation and blueshifted for forward radiation, and thus spectral broadening is noticed. These effects are much more pronounced at higher laser intensity or initial electron energy, and even give rise to higher-order harmonics that eventually lead to a continuous spectrum. However, when the electron being incident at antinode and parallelly to electric field, it only move