磁层电场仪前端信号处理电路研究  

Research of the Front-end Signal Processing Circuit for the Magnetospheric Electric Field Instrument

作　　者：胡云[1] 周斌[2] 赵华[1] 

机构地区：[1]南京航空航天大学航天学院,南京210016 [2]中国科学院空间科学与应用研究中心,北京100190

出　　处：《空间科学学报》2015年第1期104-109,共6页Chinese Journal of Space Science

基　　金：中国科学院空间科学战略性先导科技专项项目资助(XDA04060203)

摘　　要：针对磁层稀薄等离子体环境中的电场测量,设计了一种电场仪前端信号处理电路方案.双探针电场仪通过向等离子体输出驱动电流,测量两探针间的电位差,从而测量空间电场的探测仪器.在磁层稀薄等离子体环境下,等离子体阻抗较高,电场仪探针将工作在较高的工作电压上.若探针电压接近或超过电路耐压值,则可能会影响探测结果,甚至损坏电场仪.本文结合低偏置电流的电压跟随方案和反馈悬浮电源控制方案,解决了稀薄等离子体环境中电场测量的弱电流采样和高动态电位处理问题,并采用低噪声元件和特殊电路设计,控制电路噪声.测试结果显示,本方案可使探针适应±100V的悬浮电位,实现150kHz带宽的电场信号测量,且噪声小于14nV·mHz^(1/2),满足目前空间电场仪测量精度需求.A kind of front-end signal processing circuit of the electric field instrument,which would be used in the Earth's magnetosphere measurement,is investigated and presented in this work.The double-probe electric field instrument outputs drive current to the ambient plasma environment,and measures the potential difference between the two probes to detect the electric field.Plasma impedance of the magnetosphere is high,so the probe of the electric field instrument will operate in a high voltage to match the electric current requirement.When the operating voltage is close to or surpasses the circuit threshold voltage,the measuring results would be affected,and the instrument will be possibly damaged.This paper adopts voltage scheme with low bias current and feedback floating power supply control scheme,to solve the weak current sampling problem and high dynamic potential handling problem in measuring the electric field of a thin plasma.Test results show that the circuit can make the probe adapt to the floating ground in the dynamic voltage range of ±100 V.and measure the electric field from DC to 150 kHz.with a low noise level below 14nV·mHz^(-1/2),which meets the needs of electric field measurements in niagnetosphere.

关 键 词：磁层 电场探测 低噪声 悬浮电源 

分 类 号：P354[天文地球—空间物理学]