Thomson backscattering in combined fields with a general elliptical polarization

Thomson backscattering in combined fields with a general elliptical polarization of laser field and an applied constant magnetic field is studied. The monotonous and non-monotonous dependence of emission spectra on the ellipticity and the initial phase of laser field are found. We have also revealed the scaling law of the radiation spectra about the initial axial momentum in the general elliptic polarized case that is similar to the circularly polarized one. However, the scaling law about the laser intensity exists conditionally and the scale invariance about the magnetic resonance parameter exists, too. Another interesting feature is the feasibility to obtain the THz radiation by this scheme.