Nondipole effects in laser-assisted electron scattering

Abstract

Laser-assisted electron scattering is often described using the electric dipole approximation for the interaction between the electron and the assisting electromagnetic field. Within the dipole approximation, theory predicts a vanishing scattering cross section for processes involving exchange of photons in critical geometries, where the electron momentum transfer vector is perpendicular to the linear polarisation of the external field. In a nonrelativistic spin-free treatment, we consider modifications of the scattering cross section by nondipole contributions to the first order in 1/c in the interaction between the laser field and the electron using the nondipole strong-field-approximation Hamiltonian [Jensen et al. Phys. Rev. A. 101, 043408 (2020)]. The approach allows for an analytical solution for the wave function of a free electron in the laser field with a nondipole contribution.This wave function leads to an analytical formula for the laser-assisted scattering cross section including nondipole effects. The nondipole corrections depend on the propagation direction of the field relative to the electron momentum transfer vector. The approach gives a finite cross section in scattering geometries, where the dipole approach predicts a vanishing cross section. The theory is illustrated by application to scattering geometries similar to those considered in experiments where large deviations between experimental data and predictions based on the dipole approximation have been reported. In these scattering geometries, the nondipole strong-field-approximation approach suggests an increase in the cross section by orders of magnitude compared to results obtained within the dipole approximation.

Study of thermodynamics of a thermal electron in scattering

“…Jensen and Madsen, Jensen et al. designed Hamiltonian to study the differential cross section (DCS) for Laser-assisted non-thermal electron scattering in nonrelativistic spin-free case but not for thermal electron and thermodynamics properties for their work [ 7 , 8 ]. This is the research gap and in present work authors design Hamiltonian for thermal electron scattering laser field to study the thermodynamics properties of thermal electron.…”

Nondipole photoelectron momentum shifts in strong-field ionization with mid-infrared laser pulses of long duration

“…Our approach was discussed in detail elsewhere [18], and recently applied to the related process of laserassisted electron scattering [22], so the presentation here is brief. For linearly polarized light of low frequency and high intensity, it is accurate to consider the approximate nondipole strong-field-approximation Hamiltonian for an electron in an electromagnetic field [18].…”

Quantum dynamics of positron-hydrogen scattering and three-body bound state formation with an assisting laser field: predictions of a reduced-dimensionality model

“…Another aspect that motivates the present work stems from the currently growing interest in laser-assisted ion-, electron-, and positron-atom scattering [44][45][46][47][48][49][50]. With the fast development of laser technologies, intense laser fields have become a powerful tool to control and manipulate scattering processes.…”