Design Optimization of Zhangheng-1 Space Electric Field Detector

Zhangheng-1 space electric field detector with double spherical probes, as the main payload of China's 1 stSeismo-Electromagnetic Satellite (CSES), was designed and tested via ground simulation.The influence of the negative bias-current on the field detection accuracy, in different orbit plasma environments and with different sheath thicknesses, was mathematically formulated with the potential coupling model, theoretically analyzed and experimentally evaluated.The results show that the bias-current significantly increases the detection precision because of a decrease of the impedance of the probe's plasma sheath to below1×10⁵Ω.The dependence of the measured coupling potential difference between the double probes on the spherical radius was also investigated.We found that a radius greater than 3×10^-2 m resulted in the deviation coefficient α ≤ 10^-6 in the measurement.In addition, the structure, circuitry, working mode and frequency range of the novel detector was tentatively discussed.