镜像法求浅海中静态电偶极子在空气中的电磁场

The electromagnetic field in air produced by a static electric dipole located in shallow sea analyzed by mirror image theory

为对水中目标电磁特性进行数学建模及深度换算,以及对水中目标实施空中探测、定位,将镜像法应用于存在两个分界面的含导电媒质的分层媒质中,在唯一性原理的基础上,推导了空气-海水-海床三层模型下,位于海水中的任意静态电偶极子在源所在媒质区域以外的空间中—空气中的电场、磁场分布的解析表达式,并以单位偶极矩的水平电偶极子为例进行了仿真计算和特征分析.所得解析表达式为后续相关研究提供理论基础,仿真结果和文献对比,表明浅海环境下海水中的静态电偶极子在空气中也可以产生明显的电场、磁场,而且具有明显分布特征,是值得关注的目标信号.

The mirror image theory is used to a layered medium with two interfaces and a conductive medium in order to model and extrapolate the electromagnetic field of the object which is located in seawater, as well as detect and locate the object. As a result,the analytical expressions of the static electric and magnetic field in air produced by a random static electric dipole source located in seawater are derived by using the mirror image theory in the case of shallow sea model, i. e. the air-seawater-seabed three-layer model, based on the uniqueness theorem. Then a horizontal electric dipole which has unit electric moment is taken for example and some calculation is made to simulate the distribution of the electromagnetic field, and the characteristics of the distribution are analyzed. The obtained analytical expressions provide theory basis for the future research and the simulated results show that the static electric dipole which is located in shallow seawater can produce an obvious static electric field and magnetic field in air which have obvious characteristics compared with the results in previous work and should be a kind of important objective signal.