# First principle simulation of ultra-cold ion crystals in a Penning trap with Doppler cooling and a rotating wall potential

## TL;DR

This paper presents a classical simulation of ultra-cold ion crystals in a Penning trap, modeling Doppler cooling and rotating wall effects, and compares results with eigenmode analysis to validate the approach.

## Contribution

It introduces a detailed numerical simulation method for large ion crystals, incorporating Doppler cooling and trap dynamics, advancing understanding of their behavior.

## Key findings

- Simulation results agree with eigenmode analysis in frequency and mode structure.
- Doppler cooling limits axial temperature to expected values.
- The approach provides insights into large ion crystal dynamics for quantum applications.

## Abstract

A direct numerical simulation of many interacting ions in a Penning trap with a rotating wall is presented. The ion dynamics is modelled classically. Both axial and planar Doppler laser cooling are modeled using stochastic momentum impulses based on two-level atomic scattering rates. The plasmas being modeled are ultra-cold two-dimensional crystals made up of 100's of ions. We compare Doppler cooled results directly to a previous linear eigenmodes analysis. Agreement in both frequency and mode structure are obtained. Additionally, when Doppler laser cooling is applied, the laser cooled steady state plasma axial temperature agrees with the Doppler cooling limit. Numerical simulations using the approach described and benchmarked here will provide insights into the dynamics of large trapped-ion crystals, improving their performance as a platform for quantum simulation and sensing.