5.5-7.5 MeV Proton generation by a moderate intensity ultra-short laser interaction with H2O nano-wire targets

TL;DR

This study demonstrates the first generation of 5.5-7.5 MeV protons using a moderate intensity ultra-short laser interacting with water nano-wire targets, achieving high-energy proton acceleration through localized plasma effects.

Contribution

It introduces a novel method of proton acceleration utilizing water nano-wire targets and moderate laser intensities, highlighting the role of nano-wire tip enhancement in plasma dynamics.

Findings

Protons up to 7.5 MeV were generated.

Nano-wire tips enhance local laser intensity and plasma fields.

High-energy protons are produced via localized electrostatic fields.

Abstract

We report on the first generation of 5.5-7.5 MeV protons by a moderate intensity short-pulse laser (4.5 \times 1017 W/cm^2, 50 fsec) interacting with H2O nano-wires (snow) deposited on a Sapphire substrate. In this setup, the laser intensity is locally enhanced by the tip of the snow nano-wire, leading to high spatial gradients. Accordingly, the plasma near the tip is subject to enhanced ponderomotive potential, and confined charge separation is obtained. Electrostatic fields of extremely high intensities are produced over the short scale length, and protons are accelerated to MeV-level energies.