Collected current by a double Langmuir probe setup with plasma flow

Chun-Sung Jao^1*, Wojciech J. Miloch², Yohei Miyake³

¹Department of Physics, National Cheng Kung University, Tainan, Taiwan
²Department of Physics, University of Oslo, Oslo, Norway
³Graduate School of System Informatics, Kobe University, Kobe, Japan

* Presenter:Chun-Sung Jao, email:csjao899@gmail.com

The multi-needle Langmuir probe (m-NLP) is an instrument composed of two or more fixed-bias cylindrical probes designed to enhance data resolution, particularly for in-situ measurements during space missions. However, like many other spacecraft instruments, these probes can interact with the surrounding plasma, which may lead to errors in plasma measurements. In this context, we investigate how a double Langmuir probe setup interacts with plasma flow. Specifically, we examine how the electric bias and the distance between the probes affect the current collected by each probe. Results from Particle-in-Cell (PIC) simulations indicate that when a front probe and a rear probe are aligned with the plasma flow, the collected current of the rear probe can be influenced. Moreover, if the distance between the two probes is small, the entire system may experience significant effects. Additionally, we also employ test particle simulations to further illustrate how the double Langmuir probe system interacts with the surrounding plasma.

Keywords: Plasma-object interaction, Multi-needle Langmuir probe (m-NLP), Particle-in-Cell (PIC) simulation, Test particle simulation