Radiation From Particles Moving in Small-Scale Magnetic Fields Created in Solid-Density Laser-Plasma Laboratory Experiments

TL;DR

This paper explores how radiation emitted by particles in small-scale magnetic fields generated in laser-plasma experiments can serve as a diagnostic tool to understand electromagnetic turbulence.

Contribution

It demonstrates the feasibility of using radiation diagnostics to probe small-scale magnetic fields in laser-produced plasmas, linking radiation spectra to turbulence properties.

Findings

Radiation spectra differ from synchrotron and cyclotron emissions.

Feasibility of using radiation diagnostics for magnetic field analysis.

Potential to infer turbulence characteristics from emitted radiation.

Abstract

Plasmas created by high-intensity lasers are often subject to the formation of kinetic-streaming instabilities, such as the Weibel instability, which lead to the spontaneous generation of high-amplitude, tangled magnetic fields. These fields typically exist on small spatial scales, i.e. "sub-Larmor scales". Radiation from charged particles moving through small-scale electromagnetic (EM) turbulence has spectral characteristics distinct from both synchrotron and cyclotron radiation, and it carries valuable information on the statistical properties of the EM field structure and evolution. Consequently, this radiation from laser-produced plasmas may offer insight into the underlying electromagnetic turbulence. Here we investigate the prospects for, and demonstrate the feasibility of, such direct radiative diagnostics for mildly relativistic, solid-density laser plasmas produced in lab experiments.