High-quality proton bunch from laser interaction with a gas-filled cone target

TL;DR

This study demonstrates that a gas-filled cone target irradiated by an intense circularly polarized laser can produce high-energy, quasi-monoenergetic proton beams with significantly higher energies than traditional planar targets, using particle-in-cell simulations.

Contribution

It introduces a gas-filled cone target design that enhances proton acceleration efficiency and energy compared to simple planar targets, based on detailed simulation analysis.

Findings

Proton energy reached 181 MeV with GCT, nearly three times higher than planar targets.

Nonlinear focusing in gas-plasma enhances laser intensity and electron acceleration.

Stronger sheath fields from GCT improve proton beam quality and energy.

Abstract

Generation of high-energy proton bunch from interaction of an intense short circularly polarized(CP) laser pulse with a gas-filled cone target(GCT) is investigated using two-dimensional particle-in-cell simulation. The GCT target consists of a hollow cone filled with near-critical gas-plasma and a thin foil attached to the tip of the cone. It is observed that as the laser pulse propagates in the gas-plasma, the nonlinear focusing will result in an enhancement of the laser pulse intensity. It is shown that a large number of energetic electrons are generated from the gas-plasma and accelerated by the self-focused laser pulse. The energetic electrons then transports through the foil, forming a backside sheath field which is stronger than that produced by a simple planar target. A quasi-monoenergetic proton beam with maximum energy of 181 MeV is produced from this GCT target irradiated by a CP laser pulse at an intensity of $2.6\times10^{20}W/cm^2$, which is nearly three times higher compared to simple planar target(67MeV).