The Accurate Particle Tracer Code

TL;DR

The paper introduces the Accurate Particle Tracer (APT) code, a versatile, high-precision simulation platform employing advanced geometric algorithms for large-scale particle dynamics across various scientific fields.

Contribution

It presents a modular, stable, and accurate particle simulation code with new geometric numerical methods and successful deployment on a supercomputer for complex physical problems.

Findings

Demonstrated long-term numerical stability and accuracy of APT

Studied physical problems like runaway electrons and energetic particles

Distributed APT-SW on Sunway TaihuLight supercomputer

Abstract

The Accurate Particle Tracer (APT) code is designed for large-scale particle simulations on dynamical systems. Based on a large variety of advanced geometric algorithms, APT possesses long-term numerical accuracy and stability, which are critical for solving multi-scale and non-linear problems. Under the well-designed integrated and modularized framework, APT serves as a universal platform for researchers from different fields, such as plasma physics, accelerator physics, space science, fusion energy research, computational mathematics, software engineering, and high-performance computation. The APT code consists of seven main modules, including the I/O module, the initialization module, the particle pusher module, the parallelization module, the field configuration module, the external force-field module, and the extendible module. The I/O module, supported by Lua and Hdf5 projects, provides a user-friendly interface for both numerical simulation and data analysis. A series of new geometric numerical methods and key physical problems, such as runaway electrons in tokamaks and energetic particles in Van Allen belt, have been studied using APT. As an important realization, the APT-SW version has been successfully distributed on the world's fastest computer, the Sunway TaihuLight supercomputer, by supporting master-slave architecture of Sunway many-core processors.