Scaling the Yield of Laser-Driven Electron-Positron Jets to Laboratory Astrophysical Applications

TL;DR

This paper demonstrates that laser-driven electron-positron jets can be scaled up significantly in yield, enabling laboratory studies of relativistic astrophysical phenomena like collisionless shocks.

Contribution

It reports the first experimental demonstration of large-scale relativistic electron-positron jets with a quadratic energy dependence, and predicts their use in astrophysical research.

Findings

Achieved up to 30 times larger positron yields than previous experiments.

Found a quadratic dependence of positron yield on laser energy.

Predicted the use of these jets to study relativistic shocks in the laboratory.

Abstract

We report new experimental results obtained on three different laser facilities that show directed laser-driven relativistic electron-positron jets with up to 30 times larger yields than previously obtained and a quadratic (~ E^2) dependence of the positron yield on the laser energy. This favorable scaling stems from a combination of higher energy electrons due to increased laser intensity and the recirculation of MeV electrons in the mm-thick target. Based on this scaling, first principles simulations predict the possibility of using such electron-positron jets, produced at upcoming high-energy laser facilities, to probe the physics of relativistic collisionless shocks in the laboratory.