Possible Source of The Earth’s Geomagnetic Field

The earth’s geomagnetic field provides a safe environment for the earth’s biology against solar wind. However, revealing source of geomagnetic field is very challenging and it has puzzled people for several hundred years. Here, based on the previously proposed Yuheng Zhang effect, I show a simple theory to account for generation of geomagnetic field. This theory only has two requisites, one is metallic core, the other is self-rotation of the earth. Based on this theory, several interesting points are concluded: 1) negative charges accumulate at a metallic thin layer (MTL) at core-mantle boundaries (CMB) and positive charges distribute within the earth’s core; 2) rotation of the separated charges would yield geomagnetic field and gives field strength for the Earth, Ganymede and Mercury, which are in agreement with measurement values; 3) misalignment of MTL rotation axis with the earth’s rotation axis causes geomagnetic declination and a quadrupole field; 4) for a planet, a solid metallic core will generate a geomagnetic field without magnetic declination and geomagnetic reversal, and geomagnetic declination suggests a liquid metallic core; 5) dynamic evolution processes of MTL dominate long-term geomagnetic variations and reversals, e.g., a slower MTL rotation causing a geomagnetic reversal and recovery of MTL rotation eliminating geomagnetic reversal; 6) at center of the earth’s inner core, the geomagnetic field would show a reversal at a critical radius, and geomagnetic fields point from the earth’s south pole to north pole; 7) the earth’s geomagnetic pole and some quadrupoles would exhibit the same angular velocity of westward drift; 8) even if geomagnetic dipole vanished, quadrupole fields would continue to sustain and protect biology from harmful ultraviolet radiation and the solar wind; 9) absence of internal magnetic field for the Venus, Moon and Mars implies non-existence of metallic core in these planets and moons. In all, this theory provide people a new sight to understand the source of the earth’s geomagnetic field.