Design Of The Magnetospheric Three Dimensional Electric Field Instrument And The Ultra-Low Frequency Wave Particle Interaction Analyzer

Space electromagnetic environment is the important parameters of the background environment in space,and electromagnetic disturbances also in close contact with a variety of space weather events.It is an urgent need for plasma dynamics research,meteorological research and earthquake prediction to develop the electric field measurement method;it means to detect the changing characteristics of space electric field and electromagnetic wave and accurately measure space electric field.The main purpose of this dissertation is to study the core technology of the three-dimensional electric field measurement in the magnetosphere,which provides a solid foundation for the future development of the electric field instrument onboard the satellite.Moreover,the design of Ultra-Low Frequency Wave Particle Interaction Analyzer(ULF-WPIA)has also been proposed originally.This dissertation including the following work:1.In order to measure the electric field accurately(both AC and DC electric field),the electric field instrument signal system has been designed and fabricated,including preamplifier,signal process filter,differential amplifier,and these designs have been simulated in computer and PCB have been fabricated and tested.2.The boom electronic system has been designed and fabricated,including a circuit for applying a bias current(BIAS)to the probe in order to reduce the coupling resistance,and the Usher and Guard voltage bias circuits to reduce photocurrent interference.A demonstration of the Sensor Diagnostic Test(SDT)has been performed to determine the best work point by using the FPGA as controller.3.The power system of the electric field instrument has been designed and fabricated,including the digital power and analog power supply.The simulation test and PCB test have been finished.To obtain a more stable power supply also need to further optimize the design.4.The coupling resistance and the coupling voltage between the spherical probe and the plasma has been calculated quantitatively both in ionosphere and magnetosphere plasma environment;the significance of improving the measurement accuracy of the electric field and reducing the measurement error by biasing the spherical probe with current has been calculated quantitatively.The influence of the density gradient and temperature gradient on the electric field measurement has been quantitatively calculated;the input impedance of the preamplifier,together with the coupling impedance between the probe and the surrounding plasma,which can influence the measurement,has also been calculated quantitatively.The results show that the measurement errors caused by the excess of the plasma debye length and the wake effect,can be relieved by increasing the boom length.The measurement accuracy can be greatly improved by biasing the spherical probe with current,and the error caused by density gradient and temperature gradient can be relieved,too.By choosing the preamplifier that has the larger impedance or reducing the coupling impedance between the probe and the plasma can effectively improve measurement accuracy.5.The principle module of the ULF-WPIA has been designed,and each function module of the instrument has been modeled and tested.According to the test result,the error analysis has also been carried out.This dissertation has the following innovations:1.In order to study the process of the chorus wave,the EMIC wave,the ULF wave,the lower frequency waves and DC electric field interact with the charged particles,a measurement method with double rotation plane which can accurately measure the ultra-low frequency and quasi-DC part of the three-dimensional electric field has been proposed,and the corresponding model prototype has been made.The measurement method overcomes the shortcomings of the current space electric field instrument which can not accurately measure the ultra-low frequency and the quasi-DC electric field,it accurately measures the ultra-low frequency and quasi-DC part of the electric field.2.Under the premise of measuring the ultra-low frequency and quasi-DC electric field accurately,the design of the ULF-WPIA has been proposed originally,it can measure the interaction process between particles and the ULF waves or EMIC waves,and present the quantitative energies transfered between waves and particles.3.The quantitative analysis method and specific steps of calculating the coupling impedance between the probe and the plasma of the spherical electric field instrument and the application of the bias current in improving the measurement accuracy have laid a theoretical foundation for the future engineering design and data calibration analysis.Finally,the author summarizes the work of this dissertation,and points out the future direction of the design,and gives some follow-up research programs,including how to fabricate the whole system in engineering and how to improve the ULF-WPIA.