JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25ECWU04

Subject Category: Cooperative Graduate School System

PDF (to be added)

• Responsible Representative: Yasuhiro Mizobuchi, Project Manager, Aviation Technology Directorate, Aircraft Digital Transformation Technology Demonstration (XANADU) Project Team
• Contact Information: Kiyoshi Kinefuchi, Department of Aerospace Engineering, Graduate School of Engineering, Nagoya University(kiyoshi.kinefuchi@mae.nagoya-u.ac.jp)
• Members: Satoshi Inoue, Masaki Yamaguchi

Abstract

The objective of this study is to understand plasma physics phenomena in electric propulsion systems such as hollow cathode and MPD thruster. In order to investigate the distribution of plasma physics inside and outside the electric propulsion, which is difficult to measure in experiments, plasma flow inside and outside the machine is analyzed by numerical simulation.

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

By using JSS3, relatively costly calculations can be performed under various conditions when analyzing the flow field in an electric propulsion by the Hybrid-PIC or DSMC methods, because the calculations can be performed at high speed.

Achievements of the Year

Hybrid-PIC simulation of a hollow cathode

A hollow cathode enters a discharge mode characterized by unstable oscillations, known as the plume mode, when the propellant gas flow rate is reduced. Since such unstable discharges in the hollow cathode can induce instability in the entire thruster system, the boundary between the stable spot mode and the unstable plume mode represents the throttling limit of the hollow cathode. In this fiscal year, numerical simulations of the plasma inside the hollow cathode were conducted under both high-flow and low-flow operating conditions, with the aim of improving the understanding of the internal phenomena and reproducing the results obtained in the previous year. The simulation results confirmed that discharge oscillations become more pronounced as the flow rate decreases, thereby successfully reproducing the findings of the previous year.

Hybrid-PIC simulation of an MPD Thruster

In numerical analysis of MPD thrusters, ions and neutral particles have traditionally been treated as a continuum. However, this method fails to accurately capture the flow in the plume region where density decreases, as the plasma becomes too sparse for the continuum approximation to hold. Therefore, the Hybrid-PIC method was adopted, treating electrons as a fluid and ions and neutral particles as particles. This year, we refined physical models such as the sheath at the wall and electron-ion collisions, and performed analysis of an Applied-Field MPD thruster. Fig 1 shows the ion number density and ion streamlines. We compared and evaluated these analysis results with experimental results obtained from probe measurements, thereby establishing guidelines for future computations.

Fig.1: Ion streamlines and ion density

Publications

N/A

Usage of JSS

Computational Information

• Process Parallelization Methods: MPI
• Thread Parallelization Methods: N/A
• Number of Processes: 12 - 30
• Elapsed Time per Case: 24 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 0.05

Details

Please refer to System Configuration of JSS3 for the system configuration and major specifications of JSS3.

*1: Fraction of Usage in Total Resources: Weighted average of three resource types (Computing, File System, and Archiver).

*2: Fraction of Usage：Percentage of usage relative to each resource used in one year.

ISV Software Licenses Used

*2: Fraction of Usage：Percentage of usage relative to each resource used in one year.

JAXA Supercomputer System Annual Report February 2025-January 2026