正弦洋流感应电场数值模拟及分析

Numerical Simulation of Electric Fields Induced by Ocean Current with Infinite Sinusoidal Velocity

海流运动因切割地磁场会生成微弱的电流,从而在海洋及其周围空间中激发感生电场。本文基于海流感应电磁场微分方程及其边界条件,推导了水平地层正弦洋流感应电场表达式。建立海水层、海底沉积层以及地壳绝缘层构成的地电模型,模拟计算正弦洋流感应电场及感应电流密度,分析海水层和海底沉积层中感应电流分布特征,并讨论了影响洋流感应电场的因素。模拟结果表明,对于宽海流,基于地磁场垂直分量的洋流感应水平,电场在垂直剖面上近似均匀分布。由于海底导电沉积层的存在会发生电流“泄漏”,电流穿过海底界面与海水中的电流形成闭合回路。洋流感应电流在海底沉积层中的流通能力取决于其纵向电导。

Sea water moving through the Earth’s magnetic field induces electric currents and causes electromagnetic fields in the ocean and its surroundings.In this paper,the induced scalar potential and electric fields generated by ocean current with infinite sinusoidal velocity that in a three-layer geoelectric model is derived from the differential equation of the induced EM fields and its boundary conditions.We established a geoelectric model composed of seawater,seafloor sediment and insulating crust to simulate the induces electric field and the corresponding current density and analyze the distribution characteristics of induced electric field.The result showed that the horizontal electric field induced by the wide ocean current based on the vertical component of the geomagnetic field was approximately evenly distributed in the vertical section.Due to the conductivity of sediment on the seafloor,the leakage current will return and form a closed loop with the current in the seawater through the seafloor interface.The ability of induced current to flow through the sediment depends on the longitudinal conductance of the sediment.