On the Numerical Stability of the Diffusion Coefficient in Microscopic Simulations

TL;DR

This paper investigates the numerical stability of calculating the Galactic Cosmic Rays diffusion coefficient via microscopic simulations, highlighting the impact of numerical errors, especially velocity errors.

Contribution

It identifies the numerical limits and error sensitivities in microscopic simulations of cosmic ray diffusion coefficients, providing insights into computational accuracy.

Findings

Velocity errors significantly affect the diffusion coefficient calculations.

Modern computations are impacted by numerical errors, limiting accuracy.

Numerical limits for microscopic simulations are characterized.

Abstract

Nowadays, the calculation of the Galactic Cosmic Rays diffusion coefficient with direct microscopic numerical simulations is a widespread approach. In this work, we investigated the numerical limits for such calculations and demonstrated that modern computations are affected by the influence of numerical errors. We found that velocity errors have a greater impact on the result than spatial ones.