浅海中运动时谐垂直电偶极子产生的电磁场

EM fields produced by a moving,vertically-directed,time-harmonic dipole in a three-layer medium

为了对浅海中的运动舰船所产生的轴频电磁场进行建模,对三层介质中匀速运动的时谐垂直电偶极子在固定场点产生的电磁场这一问题进行了求解.首先求解在三层介质中静止的时谐电偶极子在固定场点产生的电磁场,通过狭义相对论的洛仑兹变换,得出最终的表达式.以浅海环境下低速运动的极低频时谐垂直电偶极子为例,对其在海水中的固定场点产生的电磁场进行了数值计算,通过对比计算,分析得出低速运动的偶极子与静止的偶极子所产生的电磁场相等,以及海水越浅则海底对电磁场的贡献越大等结论.最后通过实验测得的某船模的轴频电场数据,验证了表达式的实用价值.

In order to model the shaft-rate EM fields of a moving ship in shallow waters,EM fields were derived by using a fixed field point produced by a moving,vertically-directed,time-harmonic dipole which was located in a three-layer medium.First of all,EM fields at a fixed field point produced by a fixed dipole were derived,and then,based on the basic principle of the special theories of relativity and Lorentz transformation,the final expressions were derived.For example,in considering an extremely low frequency dipole moving slowly in the shallow ocean,the numerical calculations of its EM fields in the medium were carried out.Some valuable conclusions were reached through contrasting the calculation results,including findings on how the EM fields produced by the slowly moving dipole were equal to those produced by the static dipole,and how the shallower seabed produced a greater effect on the EM fields.In the end,the practical value was proven through the experimental data of some ship models.