| The space plasma environment research facility simulates the real cosmic environment.The nearearth space plasma environment simulator in this system studies the evolution laws of the basic physical processes of space plasma,thus contributing to a deeper understanding of the space plasma environment.In this process,it is an important study to discover the laws of plasma action through magnetic field.In this research,firstly the environmental characteristics of the area in the device is analyzed where the magnetic field is needed for diagnosis,and use them as the basis for designing and making the magnetic probe.The design difficulties of the magnetic probe are analyzed,and the relationship between the mutual constraints of high signal-to-noise ratio,high frequency response,and high spatial resolution is discussed,and the design parameters of the magnetic probe are determined.The spool material,wire material and other component materials of the magnetic probe are selected according to the environmental characteristics.Finally,the developed magnetic probe is calibrated for effective area and frequency response.Since the magnetic probe senses a differential signal,an integrator is designed to integrate and amplify the reduced magnetic field information.A passive integrator circuit is used to integrate the signal,which results in a very small signal,so a two-stage operational amplifier circuit is subsequently used to amplify the signal.Then,a buffer is used for impedance matching,and finally,a coaxial cable is used to connect the integrator to the acquisition system for acquisition,network transmission and storage management to ensure linear transmission of the signal.According to the simulation model of the built circuit,the validity of the integrator is verified and the influence law of the integrator is analyzed.The effect of the temperature drift of the resistor and resistance on the integrator circuit is analyzed,and the error of the output signal is 0.28%.The effect of the op-amp voltage noise on the output signal at the minimum amplitude of the signal induced by the magnetic probe is analyzed,and the error is 11%.In order to take into account the effect of the op-amp voltage noise and the incomplete fixed deviation of the integrator circuit,the time constant RC is matched,and it is determined that the peak-to-peak deviation of the magnetic induction intensity at the time constant of 4 The deviation of the magnetic induction intensity peak-to-peak is determined to be minimal at a time constant of 4.Based on the previous verification of the effectiveness of the integrator,it is found that the op-amp noise voltage and the incomplete fixed deviation caused by the integration have a great influence on the integrator output results under different values of the time constant RC.The genetic algorithm is finally chosen to construct the fitness function and find the optimal one to balance the conflicting relationship between the op-amp noise voltage and the reduction of the incomplete fixed deviation.The above completes the optimization of the integrator parameters,and in the actual fabrication of the integrator,adjustable resistors are taken to cope with the variation of the actual sensed signal.Finally,the actual integrator is connected to the magnetic probe,acquisition system,and the noise test of the integrator is performed. |
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