Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： Effects of the nonuniform feedback magnetic field on the fluxgate sensor is studied, and several typical types of the sensor are analyzed and compared mutually. It is required that the drive cores of fluxgate sensor should work in a uniform magnetic field in principle. When the magnetic field is nonuniform, error signal will be caused. Resultingly, the nonuniformity of the feedback magnetic field will lead to the change of fluxgate sensor's linear coefficient. Typical types of fluxgate sensors which work for space magnetic exploration include discrete form, Helmholtz form and Compacted Spherical Configuration (CSC) form, etc. The nonuniformity of the three feedback coils are analyzed as well as the performance of the fluxgate sensor when the feedback magnetic field is nonuniform. Compared to the simulation results, uniformity and stability of CSC sensor are much better than that of the discrete sensor, and CSC sensor is more conducive to the space magnetic field detection.
Peer Review Status:
Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： 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 150kHz, with a low noise level below 14nV?mHz~(-1/2), which meets the needs of electric field measurements in magnetosphere.
Peer Review Status:Awaiting Review
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