Scale invariance and scaling law of Thomson backscatter spectra by   electron moving in laser-magnetic resonance regime
  The Thomson scattering spectra by an electron moving in the laser-magnetic resonance acceleration regime are computed numerically and analytically. The dependence of fundamental frequency on the laser intensity and magnetic resonance parameter is examined carefully. By calculating the emission of a single electron in a circularly polarized plane-wave laser field and constant external magnetic field, the scale invariance of the radiation spectra is evident in terms of harmonic orders. The scaling law of backscattered spectra are exhibited remarkably for the laser intensity as well for the initial axial momentum of the electron when the cyclotron frequency of the electron approaches the laser frequency. The results indicate that the magnetic resonance parameter plays an important role on the strength of emission. And the rich features of scattering spectra found may be applicable to the radiation source tunability. 
Yi-Jia Fu, Chong Lv, Feng Wan, Hai-Bo Sang and Bai-Song Xie
physics.plasm-ph physics.optics