Nonlinear Ionization Dynamics of Hot Dense Plasma Observed in a Laser-Plasma Amplifier

TL;DR

This paper reports the first experimental observation of nonlinear ionization dynamics in a hot dense plasma used in a laser-plasma amplifier, revealing overionization effects that impact the development of plasma-based XUV and X-ray sources.

Contribution

It provides the first direct experimental imaging of ion abundance reshaping in a laser plasma amplifier, validated by ab initio simulations, advancing understanding of light-plasma interactions in extreme conditions.

Findings

Overionization of krypton observed due to nonlinear laser-plasma interactions

Excellent agreement between experimental data and Maxwell-Bloch simulations

Implications for scaling plasma-based XUV and X-ray light sources

Abstract

From fusion dynamics in stars, to terrestrial lightning events, to new prospects of energy production or novel light sources, hot dense plasmas are of importance for an array of physical phenomena. Due to a plethora of correlations in highly excited matter, direct probing of isolated dynamics remains challenging. Here, the 32.8-nm emission of a high-harmonic seeded laser-plasma amplifier (LPA), using eight-fold ionized Krypton as gain medium, is ptychographically imaged in longitudinal direction in the extreme ultraviolet (XUV). In excellent agreement with ab initio spatio-temporal Maxwell-Bloch simulations, an overionization of krypton due to nonlinear laser-plasma interactions is observed. This constitutes the first experimental observation of the laser ion abundance reshaping a laser plasma amplifier. The findings have direct implications for upscaling plasma-based XUV and X-ray sources and allow modeling light-plasma interactions in extreme conditions, similar to those of the early times of the universe, with direct experimental verification.