Influence of acceleration on relativistic nonlinear Thomson scattering in tightly focused linearly polarized laser pulses

The influence of acceleration of electrons on relativistic nonlinear Thomson scattering in tightly focused linearly polarized laser pulses is investigated for the first time. In the framework of classical electrodynamics, it is deduced and found that the more severe the change in the electron transverse acceleration, the stronger the asymmetry of the radiation angle distribution, and the greater the transverse acceleration, the greater the radiation energy. Tightly focused, ultrashort,and high-intensity lasers lead to violent electron acceleration processes, resulting in a bifurcated radiation structure with asymmetry and higher energy. Additionally, a change in the initial phase of the laser brings about periodic change of the acceleration, which in turn makes the radiation change periodically with the initial phase. In other cases, the radiation is in a symmetrical double-peak structure. These phenomena will help us to modulate radiation with more energy collimation.

Collision off-axis position dependence of relativistic nonlinear Thomson inverse scattering of an excited electron in a tightly focused circular polarized laser pulse

This paper presents a novel view of the impact of electron collision off-axis positions on the dynamic properties and relativistic nonlinear Thomson inverse scattering of excited electrons within tightly focused, circularly polarized laser pulses of varying intensities. We examine the effects of the transverse ponderomotive force, specifically how the deviation angle and speed of electron motion are affected by the initial off-axis position of the electron and the peak amplitude of the laser pulse. When the laser pulse intensity is low, an increase in the electron's initial off-axis distance results in reduced spatial radiation power, improved collimation, super-continuum phenomena generation, red-shifting of the spectrum's harmonic peak, and significant symmetry in the radiation radial direction. However, in contradiction to conventional understandings,when the laser pulse intensity is relatively high, the properties of the relativistic nonlinear Thomson inverse scattering of the electron deviate from the central axis, changing direction in opposition to the aforementioned effects. After reaching a peak, these properties then shift again, aligning with the previous direction. The complex interplay of these effects suggests a greater nuance and intricacy in the relationship between laser pulse intensity, electron position, and scattering properties than previously thought.

Laser parameters affecting the asymmetric radiation of the electron in tightly focused intense laser pulses

The nonlinear radiation of the electron is a distinctive feature of the action of tightly focused linearly polarized lasers.In this paper,from the perspective of radiation symmetry,the effect of laser parameters on the electron radiation power in the time domain is studied systematically.An asymmetric bimodal structure is found in the time domain in the direction of the maximum radiation.For this special structure,an explanation is given based on the electron dynamics perspective.The structure is compared with the symmetric bimodal structure in the classical theory.The increase in laser intensity,while significantly increasing the radiated power of the electron,exacerbates the asymmetry of the electron radiation.The variation in the initial phase of the laser leads to a periodic variation in the electron motion,which results in a periodic extension of the electron spatial radiation with a period ofπ.Moreover,the existence of jump points with a phase difference ofπin the range of 0-2πis found.The increase in pulse width reduces the radiated power,extends the radiation range,and alleviates the radiation asymmetry.The results in this paper contribute to the study of electron radiation characteristics in intense laser fields.