Some consequences of solar wind induction in the moon

Experiment shows the Moon to be asymmetrically excited by the solar wind in the classical spherical transverse electric mode. Both the magnetic dipole and quadrupole are noted, corresponding to Mie scattering, with the fields confined to the lunar interior. Leakage out of the antisolar cavity is evanescent below about 50 Hz. The low bulk conductivity of the interior (from inversion of magnetic signals) is two orders lower than for Earth at equivalent depth. This is consistent with a hot interior only if the rock conductivity function has anomalously low activation energy, suggesting low Fe3+ content. Extrapolation of the induction and the complementary transverse magnetic mode to the early solar system shows a consistent pattern of heating of the lunar core, surface, and asteroidal parent bodies independently of accretion or radionuclides. Thus fast highland and core formation can take place provided the induction is intensified by rapid solar spin and a pre-main sequence T Tauri-like plasma flow. (author)