There is a simple formula for computing the electric field of a time-harmonic dipole in a wholepace published in the Ward and Hohmann EM Theory chapter in the SEG EM Methods volume 1. Here I supply the Matlab code to compute the field strength and generate an .avi movie file of the field vectors in the time domain.

Below is an example screen shot of the movie. The computation was done for a seawater wholespace of 0.3 Ohm-m and a 0.25 Hz dipole transmitter oriented along the x axis (North). The view is from above and the electric field was computed at the same height as the transmitter. Colors show the strength of the polarization ellipse maximum and the arrows indicate the instantaneous direction of the electric field. The white scale bar shows a full wavelenth of the EM field (wavelength = 2*pi * skin_depth, and skin depth is approximately 0.5 *sqrt (rho*period) kilometers). The pie chart shows the phase cycle of the transmitter.

***Download the Matlab code here***

***View the Quicktime Movie here***