Gamma-ray generation in ultrahigh-intensity laser-foil interactions

TL;DR

This paper investigates gamma-ray generation via ultrarelativistic electrons in laser-foil interactions using 3D simulations, identifying optimal parameters for efficient high-energy photon production and comparing results to existing gamma-ray sources.

Contribution

It provides a detailed analysis of gamma-ray emission properties and identifies laser and plasma conditions that optimize gamma-ray yield in ultrahigh-intensity laser-foil interactions.

Findings

Efficient gamma-ray production occurs near parameters for relativistic foil motion.

Oblique laser incidence yields about 10^8 photons at 1 MeV energy.

Gamma-ray flux exceeds modern Compton gamma-ray sources.

Abstract

Incoherent photon emission by ultrarelativistic electrons in the normal incidence of a laser pulse on a foil is investigated by means of three-dimensional numerical simulations in the range of intensities $2 \times 10^{21} \text{--} 2 \times 10^{25} \text{W} \, \text{cm}^{-2}$ and electron densities $2 \times 10^{22} \text{--} 1 \times 10^{24} \text{cm}^{-3}$. We focus on properties of the resulting synchrotron radiation, such as its overall energy, directivity of the radiation pattern and slope of the energy spectrum. Regimes of laser-foil interactions are studied in the framework of a simple analytical model. The laser-plasma parameters for efficient gamma-ray generation are found and revealed to be close to the parameters for relativistic foil motion. It is shown that in the case of oblique incidence of a $3 \text{PW}$, $10 \text{fs}$ laser pulse on a thin foil about $10^{8} \text{photons}/0.1\% \text{bandwidth}$ are produced at the energy level of $1 \text{MeV}$ that significantly exceeds performance of the modern Compton gamma-ray sources. Various applications of the gamma-ray bunches are discussed.