On the upper limit of laser intensity attainable in non-ideal vacuum

TL;DR

This paper explores how residual electrons in non-ideal vacuum conditions limit the maximum laser intensity achievable, revealing a threshold around 10^26W/cm^2 due to quantum-electrodynamics cascades and energy depletion.

Contribution

It provides a detailed analysis of intensity suppression in realistic vacuum conditions, establishing an upper limit for laser intensity based on residual electron density.

Findings

Intensity suppression begins at 10^25W/cm^2

Upper threshold at 10^26W/cm^2 for residual electron density > 10^9cm^-3

Residual electrons trigger QED cascades that deplete laser energy

Abstract

The upper limit of the laser field strength in perfect vacuum is usually considered as the Schwinger field, corresponding to ~10^29W/cm^2. We investigate such limitations under realistic non-ideal vacuum conditions and find out that intensity suppression appears starting from 10^25W/cm^2, showing an upper threshold at 1026W/cm^2 level if the residual electron density in chamber surpasses 109cm^-^3. This is because the presence of residual electrons triggers the avalanche of quantum-electrodynamics cascade that creates copious electron and positron pairs. The leptons are further trapped within the driving laser field due to radiation-reaction, which significantly depletes the laser energy. The relationship between the attainable intensity and the vacuity is given according to particle-in-cell simulations and theoretical analysis. These results answer a critical problem on the achievable light intensity based on present vacuum conditions and provide a guideline for future 100's-Petawatt class laser development.