Electron emission from the focus of the Gaussian pulse

Abstract

For a symmetric trajectory of an electron in the field of a Gaussian pulse, the parameters of radiation from a section in the vicinity of the focus are studied. It is shown that the modulus of velocity and modulus of acceleration are quasi-periodic, their maxima are separated in time. The radiation of an electron in the form of plane waves in the far zone is analyzed, and the intensity distribution over the solid angle is obtained. The radiation directivity diagrams are constructed, and the time profile of the radiation power is obtained. The difference from the dipole approximation is discussed. We consider the radiation of an electron that appears in the vicinity of the focus as a result of ionization.

Counterpropagating radiation emitted by an electron in the field of a Gaussian laser pulse

“…Similarly [10,13], the vector potential of the electromagnetic field for a beam propagating along the z axis and linearly polarized along the y axis is given by the expression…”

“…where τ is the pulse width at half intensity maximum and z d is the initial distance from the time envelope maximum to the focal plane. In this work, in comparison with [10,13], a transition to a short pulse was made: the duration was reduced by a factor of 10 (τ = 15.925 →= 1.5), which corresponds to a duration of 3.5 fs. It was shown in [13] that the modules of velocity and acceleration are quasi-periodic; therefore, such a transition facilitates the numerical solution of the problem of relativistic motion.…”

“…In this work, in comparison with [10,13], a transition to a short pulse was made: the duration was reduced by a factor of 10 (τ = 15.925 →= 1.5), which corresponds to a duration of 3.5 fs. It was shown in [13] that the modules of velocity and acceleration are quasi-periodic; therefore, such a transition facilitates the numerical solution of the problem of relativistic motion. Figure 1 shows a symmetrical trajectory for kρ 0 = 26.7, τ c/λ = 1.5, γ = 5 (the size of the waist, the length of the time envelope in the oscillation periods and the peak intensity γ with respect to the relativistic one): the electron initially rests on the axis in front of the focus and after interaction stops on the axis behind the focus at the same distance.…”

“…The radiation pattern for point 3 (electron at rest) is symmetrical 'forward-backward' [13] and not symmetrical for point 2 (electron in motion) figure 3(b)…”

“…The polarization properties of electron radiation in the field of a Gaussian pulse are considered in [12]. A technique was proposed for constructing radiation diagrams of an electron [13], which also makes it possible to determine the radiation power integrated over the directions. The aim of this work is to study the radiation of an electron moving towards a laser pulse of linear polarization, depending on its initial energy.…”