基于磁光调制的方位测量系统的关键技术是磁光调制技术,交变电流驱动的含磁光材料螺线管内轴向磁场的精确表达至关重要,但是目前关于磁光材料参数特性对磁场的影响研究甚少。以磁光材料TGG晶体为例,研究了TGG介电常数变化对螺线管内部轴向交变磁场的影响。首先,当螺线管内部磁光材料的介电常数不变时,利用麦克斯韦方程建立正弦波调制下螺线管内部轴向交变磁场模型;然后根据TGG的材料构成,通过分子模拟软件VASP获得TGG的介电常数随调制信号频率变化的函数;最后将此变化函数引入到已经建立的交变磁场模型中,获得TGG介电常数变化对正弦波调制下螺线管内部轴向交变磁场的影响。结果表明:随着调制信号频率的增加,TGG晶体的介电常数减小,造成螺线管内部轴向磁场幅值衰减变缓、磁场相移衰减中的急速衰减阶段提前,且衰减速率更快。该研究思路与方法为进一步研究磁光材料对螺线管内部磁场、方位失调角测量精度的影响提供了参考。

The key technique of azimuth measurement system based on magneto-optical modulation is magneto-optical modulation technique, in which the accurate expression of the internal axial magnetic field of solenoid modulated by alternating current is important, however there is little study on effect of magnetic material's parameter characteristic in magnetic field. Take the magneto-optical material TGG crystal as an example, we study the influence of TGG dielectric constant change on the axial alternating magnetic field of the solenoid. Firstly, we assume that the dielectric constant of magneto-optical material in solenoid is a constant, the model of internal axial magnetic field of solenoid modulated by sine wave signal is established with the Maxwell's equations. Secondly, according to the molecular formula of TGG, the variation function of TGG dielectric constant with modulation signal frequency is acquired by VASP software. At last, the variation function is introduced into the established magnetic field model, and the effect of TGG dielectric constant on the internal axial magnetic field of solenoid modulated by sine wave signal is got. The results shows that when the modulation signal frequency rises, the TGG dielectric constant reduces, which slows the amplitude attenuation trend of internal axial magnetic field of solenoid, and advances the rapid attenuation stage in the magnetic field phase shift attenuation process, and speeds up the attenuation velocity of the rapid attenuation stage. The research method provides a reference for studying the effect of magneto-optical material on internal axial magnetic field of solenoid, and measurement precision of azimuth misalignment angle.