低频谐变电偶极源激发的地下电磁场的闭式解

研究偶极子源产生的电磁场在地下或水下无线电通信和地球物理勘探领域有着重要的应用价值。偶极子和介质的作用往往导致Sommerfeld型积分的解。为了深入揭示电磁波在地下的分布与传播规律,本文针对有耗媒质中为获得大探测深度和长距离通信使用的低频发射天线,在准静态近似条件下导出了水平电偶极子产生的下电磁场Sommerfeld型积分解的闭式表达式。这些公式适用于任意场区和除奇异点以外的任何场点,与数值积分相比,可显著提高计算速度。利用闭合表达式,本文还提出了一种新的场区划分方法。

The closed form expressions of the electromagnetic field in the earth by a low-frequency harmonic electric dipole

The investigation on electromagnetic fields by various dipole sources is of practical value in underground or submarine radio communication and geophysical exploration.The action of a dipole on a media results in the solution of Sommerfeld type integrals.In order to understand the laws of distribution and propagation of electromagnetic fields in the earth,we derive the closed form expressions of Sommerfeld type integrals subject to quasi static approximation for a low frequency transmitting antenna used in a losy medium for large prospecting depth and long range communication.These expressions are valid for any field zone and point except singularities and compared with the numerical integral they increase the speed of calculation.This paper also presents a new method of dividing field zones by using the closed form expressions.