Development of the floating Langmuir probe for cubesats

  • 翊臻 王

Student thesis: Master's Thesis


In recent years, the small-scale variation of the ionosphere and the re-entry process greatly draw scientists attentions. The plasma density of ionosphere in the region below 300 km varies dramatically, and electrons interact with ions frequently, the conventional Langmuir probe is not applicability of the research in this region due to its low temporal resolution. In this work, an innovated approach of the electron temperature (Te) and density (ne) measurements by an electrically floated circuit based on the principles of the double and triple Langmuir probes, named as the floating Langmuir probe (fLP), is presented. Hence, the goal of this work is to advance the a new measurement instrument based on the conventional Langmuir probe and make it suitable for cubesats to measure the plasma in the ionosphere and the atmospheric re-entry process. Comparing with the conventional Langmuir probe, fLP is designed as an electrically floating system, therefore it can measure the plasma on-board a cubesat stably with a high temporal resolution to measure the highly variating plasma during the atmospheric re-entry process. In this work, the design concept, performance analysis by simulation, hardware development and in-lab experiments of the fLP are presented. The electron temperature and density measured by the fLP at a well-floated system is verified by a well-grounded conventional Langmuir probe in the Space Plasma Operation Chamber owned by NCKU. It is demonstrated that the fLP neither influenced nor was influenced by the satellite potential variations. This instrument is capable of not only ionospheric plasma exploration, but also for the high-temperature and high-density plasma investigations around the spacecraft during its re-entry processes.
Date of Award2019
Original languageEnglish
SupervisorBing-Chih Chen (Supervisor)


  • floating Langmuir probe
  • cubesat
  • ionosphere
  • re-entry

Cite this

Development of the floating Langmuir probe for cubesats
王, 翊. (Author). 2019

Student thesis: Master's Thesis