# Monte Carlo simulation method for incoherent Thomson scattering spectra from arbitrary electron distribution functions

## TL;DR

This paper introduces a Monte Carlo simulation approach for calculating incoherent Thomson scattering spectra in high-temperature plasmas, capable of handling arbitrary electron distributions efficiently.

## Contribution

The paper presents a novel Monte Carlo method that models photon-electron interactions for arbitrary electron distributions, reducing computational costs with macro-particles.

## Key findings

- Simulated spectra agree well with analytical results for Maxwellian and kappa distributions.
- The method efficiently reproduces incoherent Thomson scattering spectra for various electron distributions.
- Validation shows the approach is reliable and computationally feasible.

## Abstract

We developed a Monte Carlo simulation method to calculate incoherent Thomson scattering spectra in high temperature plasmas. The basic idea is to treat the entire scattering process as the superposition of individual photon-electron interactions. We introduce macro-particles, referred from particle-in-cell simulations, to reduce the computational cost, and obtain scattered spectra within a reasonable computational time. Since the velocity of the interacting electron is randomly sampled from an electron distribution function, the method can be applied to arbitrary electron distribution functions provided an appropriate sampling scheme is available. We present simulation results for relativistic Maxwellian and kappa distribution functions, and compare them with both analytical and numerical spectra for validation. The simulated spectra show good agreement with both analytical and numerical results, demonstrating that the Monte Carlo simulation method can reliably reproduce incoherent Thomson scattering spectra.