Symmetric and asymmetric shocked gas jets for laser-plasma experiments

TL;DR

This paper investigates the creation and characterization of symmetric and asymmetric shocked gas jets using CFD simulations and experiments, aiming to optimize density gradients for laser-plasma acceleration.

Contribution

It introduces a novel asymmetric shocked gas jet design and validates it through combined CFD simulations and experimental measurements.

Findings

Good agreement between CFD simulations and experiments.

Asymmetric jet provides tailored density profiles for laser-plasma applications.

Parametric study identifies key parameters influencing shock formation.

Abstract

Shocks in supersonic flows offer both a high-density and sharp density gradients that can be used, for instance,for gradient injection in laser-plasma accelerators. We report on a parametric study of oblique shocks created by inserting a straight axisymmetric section at the end of a supersonic "de Laval" nozzle. The impact of different parameters such as throat diameter and straight section length is studied through computational fluid dynamics (CFD) simulations. Experimental characterizations of a shocked nozzle are compared to CFD simulations and found to be in good agreement. We then introduce a newly designed asymmetric shocked gas jet, where the straight section is only present on one lateral side of the nozzle, thus providing a gas profile that can be used for density transition injection. In this case, full-3D fluid simulations and experimental measurements are compared and show excellent agreement.