ULF/ELF/VLF Electromagnetic Fields Generated in a Sea of Finite Depth by Elevated Dipole Sources

摘要

Results are presented of a study of the amplitudes of the quasi-static electromagnetic fields produced in, on, and above the surface of a sea of finite depth by vertically-directed harmonic electric and magnetic dipoles (VED's and VMD's, respectively) and horizontally-directed harmonic electric and magnetic dipoles (HED's and HMD's, respectively). In a previous report and publication we presented numerical data for the fields produced on and above the surface of the sea by the dipole sources when submerged in the sea. We now present data for the fields produced in the sea by the same dipole sources when they are either on or elevated above the surface. The primary purpose of these computations is to determine the conditions under which an electrically-conducting sea bed can produce significant changes in the fields generated by the dipoles, as compared with the fields produced in, on, and above an infinitely deep sea, for frequencies in the ULF, ELF, and VLF bands (frequencies less than 30 kHz). The present work shows that the fields produced in the sea by elevated dipoles are comparatively little affected by the presence of the sea floor.