Particle dynamics and deviation effects in the field of a strong electromagnetic wave

TL;DR

This paper investigates the motion and deviation of particles, including charged and spinning particles, in the field of a strong electromagnetic wave within general relativity, analyzing different radiation flux profiles and their observable effects.

Contribution

It provides a detailed analysis of test particle dynamics, including deviation and spin effects, in strong electromagnetic wave backgrounds with exact solutions in general relativity.

Findings

Test particle trajectories differ significantly between constant and oscillating radiation flux profiles.

Charged particles experience inverse Compton scattering effects in the gravitational-electromagnetic field.

Spin vectors can change orientation, leading to observable spin-flip phenomena.

Abstract

Some strong field effects on test particle motion associated with the propagation of a plane electromagnetic wave in the exact theory of general relativity are investigated. Two different profiles of the associated radiation flux are considered in comparison, corresponding to either constant or oscillating electric and magnetic fields with respect to a natural family of observers. These are the most common situations to be experimentally explored, and have a well known counterpart in the flat spacetime limit. The resulting line elements are determined by a single metric function, which turns out to be expressed in terms of standard trigonometric functions in the case of a constant radiation flux, and in terms of special functions in the case of oscillating flux, leading to different features of test particle motion. The world line deviation between both uncharged and charged particles on different spacetime trajectories due to the combined effect of gravitational and electromagnetic forces is studied. The interaction of charged particles with the background radiation field is also discussed through a general relativistic description of the inverse Compton effect. Motion as well as deviation effects on particles endowed with spin are studied too. Special situations may occur in which the direction of the spin vector change during the interaction, leading to obsevables effects like spin-flip.