# Structure-preserving geometric particle-in-cell algorithm suppresses finite-grid instability -- Comment on "Finite grid instability and spectral fidelity of the electrostatic Particle-In-Cell algorithm'' by Huang et al

## TL;DR

This paper demonstrates that the Structure-preserving geometric particle-in-cell (SPG-PIC) algorithm effectively suppresses finite-grid instability, improving spectral fidelity in plasma simulations, as confirmed by numerical experiments.

## Contribution

It provides the first numerical validation that the SPG-PIC algorithm can suppress finite-grid instability, enhancing the stability of PIC simulations.

## Key findings

- SPG-PIC suppresses finite-grid instability
- SPG-PIC maintains spectral fidelity
- Numerical experiments confirm stability improvements

## Abstract

A recent paper by Huang et al. [Computer Physics Communications 207, 123 (2016)] thoroughly analyzed the Finite Grid Instability(FGI) and spectral fidelity of standard Particle-In-Cell (PIC) methods. Numerical experiments were carried out to demonstrate the FGIs for two PIC methods, the energy-conserving algorithm and the momentum-conserving algorithm. The paper also suggested that similar numerical experiments should be performed to test the newly developed Structure-Preserving Geometric (SPG)-PIC algorithm. In this comment, we supply the results of the suggested numerical experiments, which show that the SPG-PIC algorithm is able to suppress the FGI.