Influence of beam waist radius on radiation characteristics of high energy electron and laser pulse collision

With the help of MATLAB numerical simulation, the motion trajectory as well as temporal and spatial radiation characteristics of high-energy electrons colliding with circularly polarized tightly focused lasers with different beam waist radii are investigated in the framework of electrodynamic and nonlinear Thomson scattering. The results reveal that the maximum amplitude of electron motion is negatively correlated with the waist radius. The spatial radiation power increases initially, followed by a decrease with the growth of the waist radius. Moreover, when the waist radius is greater than or equal to 4 times the laser wavelength (lambda(0)), the waist radius has little effect on the electron motion trajectory and spatial radiation characteristics. The time spectrum and frequency spectrum of the laser beam with a waist radius of 4 lambda(0) are analyzed. It is found that the head-on collision of a single counter-current electron with a circularly polarized laser pulse in the direction of maximum energy radiation (phi = 2 degrees, theta = 146.5 degrees) can produce an ultra-intense pulse with attosecond duration. Moreover, we have found an optimal viewing angle range to facilitate the operation of researchers in actual experiments.