Electronics for Langmuir Probe Measuring Plasma Density in the Ionosphere of Mars : MOM - 2

Electronics and Comminication Engineering

Langmuir probes have been installed on satellites and sounding rockets to observe the general characteristics of thermal plasma in the ionosphere for more than five decades. Because of its simplicity and convenience, the Langmuir probe is one of the most frequently installed scientific instruments on spacecraft. A conducting sensor called probe is fixed to the medium under monitoring to collect the current using the probe is measured to examine various plasma parameters in the MARS ionosphere. As the current is proportional to the ambient plasma density; typically a sweep bias voltage is supplied to the sensor and the current-voltage characteristics are used to study plasma parameters. The automatic gain switching system is used to gain the current in desired voltage range. It works on basic principle of the Langmuir Probe. In this paper, we describe the design, implementation and laboratory test results. The Langmuir Probe experiment consists of gold coated cylindrical sensor as the input stage of the system. The sweep voltage is applied to the sensor for generating current. By keeping the sensor in plasma, it collects the current and its current-voltage characteristics analysis suggests the plasma parameters like electron density, ion density, electron temperature etc. The low pass filter are used to remove unwanted frequency of signal later. This paper describes the primary scientific objectives of the Langmuir Probe experiment and the technical capabilities of the instrument.

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