# Collisionless shock acceleration of quasi-monoenergetic ions in ultra-relativistic regime

## TL;DR

This paper explores how ultra-relativistic laser-plasma interactions can accelerate ions via collisionless shocks, considering radiation reaction and pair production effects, and finds optimized target conditions for better ion acceleration.

## Contribution

It introduces the effects of radiation reaction and pair production into collisionless shock acceleration simulations, revealing their impact on ion energy and acceleration dynamics.

## Key findings

- Radiation reaction and pair production slow shock velocity and reduce ion energy.
- Tailored density profiles improve ion acceleration energy.
- Slab targets produce lower energy spread.

## Abstract

Collisionless shock acceleration of carbon ions (C$^{6+}$) is investigated in the ultra-relativistic regime of laser-plasma interaction by accounting for the radiation reaction force and the pair production in particle-in-cell simulations. Both radiation reaction force and pair plasma formation tend to slow down the shock velocity, reducing the energy of the accelerated ions, albeit extending the time scales of the acceleration process. Slab plasma target achieves lower energy spread while target with a tailored density profile yields higher ion acceleration energies.