One of the most fundamental problems of physics related to our planet concerns the nature of the mechanism that generates the geomagnetic field and the energy source for powering it. J. Marvin Herndon has already demonstrated the feasibility of a nuclear fission georeactor at the center of the Earth as the energy source for the geomagnetic field. Now, he suggests that the mechanism for generating the geomagnetic field and the energy source for powering it are one and the same, a nuclear georeactor at the center of the Earth.

Chandrasekhar, pictured at left, explained thermal convection this way: “The simplest example of thermally induced convection arises when a horizontal layer of fluid is heated from below and an adverse temperature gradient is maintained. The adjective ‘adverse’ is used to qualify the prevailing temperature gradient, since, on account of thermal expansion, the fluid at the bottom becomes lighter than the fluid at the top; and this is a top-heavy arrangement which is potentially unstable. Under these circumstances the fluid will try to redistribute itself to redress this weakness in its arrangement. This is how thermal convection originates: It represents the efforts of the fluid to restore to itself some degree of stability.”

The Earth's fluid iron-alloy core has high thermal conductivity and it is surrounded by an extremely thick blanket of mantle rock which has quite low thermal conductivity, a very good thermal insulator. To maintain the "adverse temperature gradient", the top being cooler than the bottom, as required for convection, would require an efficient means for continuously removing heat from the top of the core. Moreover, the fluid iron-alloy core is unfavorable for the presence of electric charge separations or transient magnetic fields which are needed to "seed" the dynamo magnetic field amplifier. There is another possibility, one that that no one before had considered.

A dynamo mechanism operating in the georeactor sub-shell, as suggested by Herndon, pictured at right, would obviate those problems. It would have an intense source of heat at the bottom of the fluid sub-shell and a massive thermally conducting heat sink at its top. There would be ample sources of electrical "seed" charges from radioactive decay and from the effects of ionizing radiation. The dynamo mechanism operating in the georeactor sub-shell would be smaller, more compact, would produce its own nuclear heat, and would have a micro-gravity environment in which to operate.

See, J. Marvin Herndon (2007) Nuclear Georeactor Generation of the Earth's Geomagnetic Field. Current Science 93, 1485-1487. (click here for pdf)