Planetary space simulations based on the particle description for electrons and ions.

Introduction

The question about how solar storms impact a planet has both fundamental scientific importance and great social impacts for protecting our infrastructure from the most powerful solar storms. At present, models rely on a fluid description of the electrons due to algorithmic and computational challenges.

Project Goal

Our goal is to develop a model of the space environment around a planet based on a particle description of both ions and electrons. We plan to use the particle in cell (PIC) model where both ions and electrons retain their nature as particles. This PIC model will allow us to investigate the critical role of energetic electrons participating in the energy and matter transfer from the solar wind to the planet's inner space.

Methodology

What makes this goal now possible is the Energy Conserving semi-implicit method (ECsim), developed by the PI. The ECsim conserves energy exactly, a critical element in the investigation of energy flow from the solar wind.

In addition, the energy conservation leads to enhanced numerical stability, which in turn greatly augments ECsim’s capability to simulate very large systems such as planet atmospheres while treating electrons as particles rather than fluid.

Innovations

We will start from this new development and introduce two critical innovations:

1. Adaptive Spatial and Temporal Resolution: We will implement adaptive spatial and temporal resolution for finer resolution closer to the planet and in selected areas of interest.
2. CPU-GPU Algorithms: We will implement CPU-GPU algorithms for the new heterogeneous supercomputers developed by EuroHPC.

Expected Outcomes

These innovations will increase the capability of ECsim by more than an order of magnitude, making it possible to model a region as big as the Earth's space environment with the computers available within the next 3-5 years.

If successful, we will have the first PIC model to describe a planetary space environment where the correct particle nature of the electrons is considered with all its implications for energy and matter transport.