Prompt electrons driving ion acceleration and formation of a two temperatures plasma in nanosecond laser-ablation domain

TL;DR

This study investigates plasma formation during nanosecond laser ablation at high intensity, revealing prompt electron emission, complex plasma fragmentation, and a dual-temperature plasma, supported by experimental data and 1D PIC simulations.

Contribution

It demonstrates the crucial role of prompt electrons in plasma dynamics and introduces a comprehensive explanation for observed phenomena at this laser intensity regime.

Findings

Prompt electrons are emitted during laser ablation at 10^12 W/cm^2.

A double electron temperature persists in the plasma for extended periods.

Experimental results align with 1D PIC simulations when prompt electron emission is included.

Abstract

We present the results of an experiment on plasma generation via laser ablation at 10^12 W/cm^2 of power intensity and in a nanosecond domain. Prompt electrons emission and complex plasma plume fragmentation were simultaneously observed for the first time in this laser intensity regime, along with a double electron temperature inside the plasma bulk surviving for a long time to the plume expansion. 1D PIC simulations are in agreement with experimental data as long as the emission of initial prompt electrons is considered. This assumption results to be the key to explain all the other experimental evidences.