Measurement of Electron Distribution Function in Space Plasma Operation Chamber

• Main Authors: Wen-HaoChen, 陳文晧
• Other Authors: Chio-Zong Cheng
• Format: Others
• Language: en_US
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/04544251403441517815

碩士 === 國立成功大學 === 太空與電漿科學研究所 === 102 === Langmuir probe is a commonly used instrument for measuring the electron density and temperature in the ionosphere. The measurement of electron distribution function (EDF) is also an important application of the Langmuir probe measurement. The typical EDF dynamic range of the Langmuir probe measurement is about 2~3 orders of magnitude, which is too small to measure EDF in wide energy range due to the small signal-to-noise (S/N) ratio. In addition, the Langmuir probe measurement on small satellites suffers the effect of finite satellite/probe surface area ratio, which causes inaccurate measurement results. Hence, the goal of this thesis is to develop a new system to measure EDF with large dynamic range and large S/N ratio, and the new device can theoretically avoid the effects of finite satellite/probe surface area ratio on the EDF measurement on small satellites. We will describe the Langmuir probe system design and electronic circuits, the development of a new device for measuring EDF using the channel electron multiplier, and experimental results obtained in Space Plasma Operation Chamber of the Plasma and Space Science Center at National Cheng Kung University. We also investigate the effect of finite satellite/probe surface area ratio on the Langmuir probe measurement, which needs to be considered when the Langmuir probe is deployed onboard small satellites.