Research Of Sensor And Front-end Signal Magnify Circuit For Electric Field Detection Of MIT Magnetosphere Spacecraft

This paper introduces a kind of front-end circuit design using suspension potential method tomeasure the electric field of thin plasma. The design will be applied in the magnetosphere star of theMagnetosphere-Ionosphere-Thermal coupling satellite constellation exploration program (MIT),carried out by Chinese Academy of Center for Space Science and Applied Research. Because of thecharacteristic of the magnetosphere, thin layers of plasma, the plasma impedance is high, and theelectric potential of is of large dynamic range (±100v), in the current drive mode. To solve theproblem of large voltage driven by the weak current, this paper, through studying the characteristics ofmagnetosphere plasma and space electric field detection method, proposes a novel solution, thesuspension potential method, and designs the sensor and its built-in low noise amplifier circuit, highisolation suspended power and the precise drive current (including stretch current) circuit. The circuitsystem strictly controls the circuit noise, and secondary photoemission escape from the surface of thesensor and the stretch. The experiments show that the circuit can work stably in large range of voltage(±100v), has wide frequency range (150KHz), and has low electric field noise (6.7uV/m), which inline with the MIT project requirements. Experiment shows that the circuit’s technical indicators areclose to similar foreign satellites.