ULF/ELF electromagnetic fields produced in a conducting medium of infinite extent by a linear current source of finite length

A linear current source of finite length embedded in a conducting medium of infinite extent is considered. Assuming a sea-water medium, the components of the electric and magnetic fields are numerically evaluated for two frequencies in the ULF/ELF range (frequencies less than 3 kHz). Comparison is made between the electric field vectors produced at the two different frequencies, and curves are plotted for one of the frequencies showing the variation with distance of the amplitudes of the electric and magnetic field components. A parametric approach is outlined that generalizes the field data presented in the figures and which enables the data to be extended to conducting media other than sea water and to other frequencies in the ULF/ELF range. Some practical applications of the data are discussed.