Peak amplitude dependence of radiation properties of nonlinear Thomson scattering under an applied magnetic field

The present study systematically investigates the peak amplitude dependence of nonlinear Thomson scattering radiation under an applied magnetic field through theoretical modelling and numerical simulations. A framework is established for the analysis of electron dynamics, spatial patterns and spectral distribution in combined fields of tightly focused circularly polarised Hermite-Gaussian lasers ( a 0 = 1–20) and magnetic fields ( B 0 = 0.5 kT). The findings of the study indicate a non-monotonic relationship, whereby optimal performance is observed at a 0 = 10, accompanied by exceptional collimation (angular divergence <2.5°) and peak intensity (approximately 10 7 ).This represents a 1,000-fold enhancement over low-amplitude regimes ( a 0 < 3). Spectral analysis reveals supercontinuum harmonics extending to ω/ω 0 > 4,000, with maximum power concentrated at polar angles θ m ≈ 2.5°. These findings advance magneto-optical control of relativistic scattering and provide guidelines for the optimisation of compact X-ray sources.