Mr. Chen Cui is currently a Ph.D. candidate in the Department of Astronautical Engineering at the University of Southern California. He also received his Master’s degree in High-performance Computing at the University of Southern California. Before joining the University of Southern California, he earned his Bachelor at Beihang University in 2017. Chen Cui’s research is multidisciplinary, sitting at the intersection of plasma dynamics, aerospace engineering, and high-performance computing. Specifically, his research focuses on the first principle modeling of space plasma flow with applications to electric propulsion thrusters, solar wind turbulence and instability. The goal of his research is to build bridges between microscopic physics and macroscopic dynamics for space plasma flow. Chen Cui is the primary developer of the large-scale parallelized kinetic modeling framework, Vlasolver.

Predictive Modeling of Space Plasma Flows: Building Bridges between Microscopic Physics and Macroscopic Dynamics

In recent years, there have been several missions proposed, aiming to land on the moon, and explore Mars and deep space. Compared to the missions on LEO and GEO orbit, these missions typically have a longer duration and longer distance. The long durations of these missions require a better understanding of spacecraft interactions with the space environment (primarily, solar wind) and the long distance makes electric propulsion thrusters a good candidate for the propulsion system.

Understanding the plasma flows in electric propulsion thrusters and the plasma flows in solar wind can help to ensure the success of these missions. The space plasma flows are rarefied and collisionless and thus typically deviate from the equilibrium state. The non-equilibrium nature of space plasma flows requires kinetic models to study the essential physical processes. However, the large computational cost of kinetic models hinders the use of kinetic models in engineering. On the other hand, fluid models which are frequently used in engineering can not capture the necessary physics processes in space plasma flows and may cause large errors. In order to help engineers and scientists with mission design, an accurate, fast predictive modeling method of space plasma flows needs to be developed. One way to establish such a model is to use hybrid models with properly designed electron fluid closures. However, how to construct the electron fluid closure remains a poorly understood problem.

In this talk, Mr. Cui will discuss the relations between electron microscopic kinetics and macroscopic plasma flow dynamics and discuss the influence of these relations on building a proper electron fluid model. Three example problems, 1D and 2D plasma expansion and the interplay between the whistler turbulence and instability in the solar wind, will be discussed to show the importance and effects of microscopic kinetics on macroscopic dynamics. He will also introduce and talk about the novel grid-based noise-free kinetic method, the grid-based Vlasov method, used in this work.