Quantitatively consistent computation of coherent and incoherent radiation in particle-in-cell codes - a general form factor formalism for macro-particles

TL;DR

This paper introduces a general form factor formalism for particle-in-cell codes that accurately computes coherent and incoherent radiation from macro-particles, enabling large-scale simulations with billions of particles.

Contribution

It presents a novel formalism and an efficient implementation for self-consistent radiation calculations in PIC simulations, improving accuracy and scalability.

Findings

Demonstrated impact on radiation spectra in LWFA simulation

Enables simulations with billions of macro-particles

Provides a memory-efficient implementation

Abstract

Quantitative predictions from synthetic radiation diagnostics often have to consider all accelerated particles. For particle-in-cell (PIC) codes, this not only means including all macro-particles but also taking into account the discrete electron distribution associated with them. This paper presents a general form factor formalism that allows to determine the radiation from this discrete electron distribution in order to compute the coherent and incoherent radiation self-consistently. Furthermore, we discuss a memory-efficient implementation that allows PIC simulations with billions of macro-particles. The impact on the radiation spectra is demonstrated on a large scale LWFA simulation.