Lunar Surface Electromagnetic Sounding: A Theoretical Analysis

A theoretical analysis of the radiated fields and their polarization parameters has been made for a horizontal magnetic dipole situated on the surface of a layered half-space. With a view to using the system mounted on a lunar surface vehicle, two transmitter-receiver separations of 3 and 10 m, respectively, have been considered. A number of planar models of the lunar interior have been envisioned with various thicknesses of a debris top layer and with a second layer consisting of dry rock, 1 percent water-bearing wet rock and permafrost, respectively. A study of the results shows that resolution of layers can be achieved to depths of 20 m for these separations. The presence or absence of water in the lunar subsurface, for the materials that might exist in the moon, is clearly indicated by the characteristic signatures obtained over the frequency range of 103 to 107 Hz. The amplitude and phase of the vertical component of the magnetic field and the tilt angle, and the ellipticity of the magnetic polarization ellipse seem to be the most diagnostic parameters.