Research And Implementation Of Plasma Electron Density Detection System Based On Multiple Langmuir Probe

Langmuir probe technology is widely used in the diagnosis of space ionospheric plasma parameters.Compared with the detection method of space ionosphere using radio waves,the in-situ measurement of Langmuir probe technology can be obtained more accurately and directly Space ionospheric plasma parameters.In recent years,as the aerospace market continues to increase,the development of microsatellite technology has attracted more and more attention from professionals around the world.Microsatellites have small size,light weight,good performance,short development cycle,low cost,and flexible launch methods.Characteristics,has been widely used in communications,remote sensing,reconnaissance and other fields.In the space environment where micro-satellites operate,there are irregular plasma structures of various scales.These structures have a severe impact on the satellite's own operational safety and satellite communications.Therefore,it is very important to monitor and warn the space environment of satellite operations.At present,most plasma detectors generally have the problem of low spatial resolution for obtaining ionospheric plasma parameters.In China,satellite ionospheric plasma detection loads are still dominated by conventional detection loads,which have not yet been miniaturized and are not suitable for use as micro-satellite loads.Therefore,the development of a miniature,low power consumption,high spatial resolution ionospheric plasma diagnostic system is of great significance for the study of space plasmaThis paper designs and implements a Doran Muir probe plasma diagnosis system based on STM32 microprocessor,which is mainly composed of hardware circuit and software program.In view of the shortcomings of traditional diagnostic methods,a measurement scheme that can achieve high spatial resolution by combining two probes is proposed.In order to ensure the redundancy of the diagnostic system and the continuity of diagnostic data,four sampling channels are set in the hardware circuit,which are respectively a scanning bias probe diagnostic channel and three fixed bias probe diagnostic channels.The scanning channel can realize the continuity of the volt-ampere characteristic curve within the 0-10V scanning bias voltage,and the electron temperature in the plasma can be obtained through the continuity curve;three fixed bias probe diagnostic channels combined with optimized theoretical formulas to achieve high spatial resolution Electronic density diagnosis function.The hardware circuit of the probe diagnosis system is composed of a data acquisition control module,a power supply circuit,a micro-current detection circuit and a filter circuit.The data acquisition control module is realized by the STM32F373 chip,which mainly completes high-speed data acquisition,scanning bias signal output and data interaction.The integration of multiple functional modules reduces the size and weight of the system;the micro-current detection uses a feedback current measurement circuit to The current voltage signal,combined with the on-chip 16-bit ADC,provides a guarantee for the detection accuracy of small currents;the filter circuit uses a programmable eight-order low-pass filter combined with passive filtering to improve the system's filtering effect on interference signals.The software program includes two parts:the hardware driver and the host computer management program.The hardware driver mainly implements functions such as bias voltage scanning,multi-channel acquisition,and data transmission.The data transmission module guarantees the reliability and accuracy of data transmission,and formulates the corresponding data transmission protocol;in the host computer management program,it designs and implements the functions of the host computer software to control the hardware system,collect data storage,and display real-time images.In order to ensure the smoothness of the displayed curve,the SG filter algorithm is added to the host computer softwareAt present,the system has conducted diagnostic tests in the plasma vacuum chamber.Compared with traditional diagnostic systems,the system can obtain plasma parameters faster.The plasma parameters obtained by the system diagnosis are reasonable and used in the detection of the plasma vacuum chamber.