Proton beams with controlled divergence and concentrated energy in TNSA regime by USUI laser pulse interaction with a tailored hole-target

TL;DR

This paper demonstrates that using a tailored hole-target in TNSA with USUI laser pulses can produce proton beams with controlled divergence and concentrated energy, improving beam quality for applications.

Contribution

The study introduces a novel target design that reshapes electric fields to control proton beam divergence and energy density in TNSA, supported by detailed PIC simulations.

Findings

Tailored hole-targets effectively suppress proton beam divergence.

Electric field reshaping leads to focused, high-energy proton beams.

Dependence of beam properties on hole depth is quantitatively analyzed.

Abstract

An improved acceleration scheme to produce protons with controlled divergence and concentrated energy density is studied using ultrashort ultraintense (USUI) laser pulse interaction with a tailored hole-target in target normal sheath acceleration (TNSA) regime. Two-dimension-in-space and three-dimension-in-velocity (2D3V) particle-in-cell (PIC) simulations show that the tailored hole-target helps to reshape the sheath electric field and generate a transverse quasistatic electric field of $TV/m$ along the inner wall of the hole. The transverse electric field suppresses the transverse expansion of the proton beam effectively, as it tends to force the produced protons to focus inwards to the central axis, resulting in controlled divergence and concentrated energy density compared with that of a single plain target. The dependence of proton beam divergence and energy feature on depth of the hole is investigated in detail. A rough estimation of the hole depth ranges depending on $a_{0}$ of the incident laser is also given.