Study On Atmospheric Electric Field Measurement Based On Pockels Effect

As a lightning monitoring equipment, atmospheric electric field mill can real-time monitoring the electric field. Common atmospheric electric field measurement device often have some shortcomings, like bulky、electromagnetic interference、narrowly measurement bandwidth and so on. Therefore, it is necessary to invent a new type sensor of atmospheric electric field with the characteristics as small size, anti-interference ability, wide measurement band, etc.This paper advanced a new way to measure atmospheric electric field which is based on the research of Pockels effect, designed a pulse electric field sensor which was based on Pockels effect of BGO crystal. In order to reduce the sensor cost, the author proposed that using BSO crystal as a sensor instead of the BGO crystal material, given the production method; than, designed a high speed data acquisition system for lightning transient electric field measurement. Specific studies are as follows:Firstly, this paper designed a pulse electric field sensor which was based on Pockels effect of BGO crystal. Given schematic view of the sensor and the system block diagram, the choice of optics has been described. Analyzed the choice problem of crystal and light source, and others which appeared during the course of design this sensor, According to the analog simulation, this method of measuring atmospheric electric field is workable, in this way it afford a basis for further design of this atmospheric electric field sensor and improving it’s performance.Secondly, For the purpose of solving the impact problem of rotation effect on electro-optical effect for lightning electric field sensor design using BSO crystal, studied the theory of light propagation equations. Based on the study of effect on the state of polarization of light by BSO crystal’s electro-optic effect and rotation effect, we derived the optical transmission equation of BSO crystal in the external electric field, and the intensity of the transmitted light. Studied the effect of rotation effect on electro-optical effect of BSO crystal, Proposed method to eliminate the rotation effect by theoretical analysis. and proved the feasibility of BSO crystal as lightning electric field sensor material by the analog simulation.Finally, this paper using the A/D conversion chip AD9057and the lightning electric field sensor which based on Pockels effect designed a high speed data acquisition system for lightning transient electric field measurement, given the hardware circuit and software program flow diagram of this high speed acquisition system。Based on the design of hardware and software for the lightning field high speed acquisition system, the problem of speed matching between high speed A/D converting speed and low speed intelligent management when received the data from sensor have being solved,and achieved0-10MHz bandwidth lightning transient electric field signal acquisition, it has important actual value.