Multi-photon enhancement of the Schwinger pair production mechanism under strong FEL radiation

G Mouloudakis,P Lambropoulos

doi:10.1016/j.physletb.2020.135987

Abstract

In this work we study the production of electron-positron pairs from vacuum in presence of a field resulting from the collision of two counter-propagating FEL beams that undergo Gaussian amplitude fluctuations. Our work aims to the extension of previous works based on the standing wave hypothesis, by including the inherent stochastic amplitude fluctuations of the individual FEL beams. As shown, depending on the order of the process, a large non-linear enhancement in the number of created pairs can be expected over a big intensity window in the multi-photon regime. Vacuum pair creation in view of future plans on the production of ultra-strong and high energy radiation in FEL facilities is also discussed.

Highlights

The spontaneous production of electron-positron pairs in vacuum in the presence of ultrastrong electromagnetic radiation, is one of the most intriguing non-linear phenomena predicted by Quantum Electrodynamics (QED) theory, which still has not been confirmed experimentally
The article is organized as follows: In Sec. 2 we provide a brief discussion about the conservation laws of Schwinger pair creation and examine the problem of pair creation under the standing wave hypothesis in the presence of field amplitude fluctuations
Given that the parameter γ is expressed in terms of the intensity as γ and that the minimum number of photons participating in the process is

Summary

Introduction

The spontaneous production of electron-positron pairs in vacuum in the presence of ultrastrong electromagnetic radiation, is one of the most intriguing non-linear phenomena predicted by Quantum Electrodynamics (QED) theory, which still has not been confirmed experimentally. It is known that the rate of an N-photon process, far from resonance with real intermediate states, depends on the Nth order intensity correlation function [61,62,63,64]. The situation becomes much more complex when for a smooth pulse the rate is a complicated function of the intensity, as that entails the dependence of the rate on a complicated function of a stochastic variable In that case, it is far from evident whether averaging over the fluctuations will lead to enhancement of the rate.

Conservation laws and the standing wave hypothesis

N0 Ic ωτ 2π

Results and Discussion