The importance of temperature-dependent collision frequency in PIC simulation on nanometric density evolution of highly-collisional strongly-coupled dense plasmas

TL;DR

This paper demonstrates that a 1D3V PIC simulation incorporating temperature-dependent collision frequency can accurately model nanometric density evolution in highly-collisional, strongly-coupled dense plasmas near the Fermi temperature, aligning well with experimental data.

Contribution

The study introduces a PIC simulation with realistic collision frequency at the Fermi temperature, enhancing modeling accuracy for dense plasmas at nanoscales.

Findings

PIC simulation matches experimental results up to 2 ps.

Simulation accurately captures nanoscale plasma dynamics.

Temperature-dependent collision frequency improves simulation reliability.

Abstract

Particle-in-Cell (PIC) method is a powerful plasma simulation tool for investigating high-intensity femtosecond laser-matter interaction. However, its simulation capability at high-density plasmas around the Fermi temperature is considered to be inadequate due, among others, to the necessity of implementing atomic-scale collisions. Here, we performed a one-dimensional with three-velocity space (1D3V) PIC simulation that features the realistic collision frequency around the Fermi temperature and atomic-scale cell size. The results are compared with state-of-the-art experimental results as well as with hydrodynamic simulation. We found that the PIC simulation is capable of simulating the nanoscale dynamics of solid-density plasmas around the Fermi temperature up to $\sim$2~ps driven by a laser pulse at the moderate intensity of $10^{14-15}$~$\mathrm{W/cm^{2}}$, by comparing with the state-of-the-art experimental results. The reliability of the simulation can be further improved in the future by implementing multi-dimensional kinetics and radiation transport.