Subpicosecond dynamics of pre-plasma on a solid, formed by a ultra-high contrast, relativistic intensity pulse

TL;DR

This study employs spectral interferometry to measure subpicosecond pre-plasma dynamics on solid targets created by ultra-high contrast, relativistic intensity laser pulses, providing insights crucial for laser energy coupling in fusion and ion acceleration.

Contribution

It introduces a precise spectral interferometry method to measure ultra-fast pre-plasma scale lengths and early expansion dynamics with subpicosecond resolution.

Findings

Pre-plasma scale lengths range from 3 to 15 nm.

Pre-plasma expands within less than 12 ps.

Measurement technique enhances understanding of laser-plasma interactions.

Abstract

Using spectral interferometry technique, we measured subpicosecond time-resolved pre-plasma scale lengths and early expansion ($<$ 12 ps) of the plasma produced by a high intensity (2$\times$10$^{18}$ W/cm$^{2}$) pulse with ultra-high contrast (10$^{-9}$). We measured pre-plasma scale lengths in the range of 3-15 nm. This measurement plays a crucial role in understanding the mechanism of laser coupling its energy to hot electrons and hence important for laser-driven ion acceleration and fast ignition approach to fusion.