Thermionic phenomena of the Earth's core and its effect on the geomagnetic field

Abstract

In this model, we will show that the high-density quasi-plasma forms at the outer surface of the outer core and accounts for the geomagnetic field. The level of thermo-ionization at the outer surface of Earth's outer core is investigated. The density and the frequency of the plasma formed by the thermion are obtained. The high-density plasma formed by ionization can block the electromagnetic field and prevent it from penetrating the outer core. Thermion has been well researched by physicists. In general, most of metals have large thermionic emissions when their temperatures are above 1500K. The Emission Current Density of iron at this temperature is ~10⁻¹ A/m² and rise sharply with temperature increases. The earth's outer core is liquid and consists primarily of iron with temperatures in excess of 4000K. The core mantle boundary temperature might reach 4800K or even higher and the emission current density for iron at this temperature is over 10⁸A /m². Equilibrium between electron emission from the outer core and electron attracted to the outer core is reached when the surface positive charge density is around 10⁻³ to 10⁻⁵ C/m² at the surface of the outer core. The electrons within the mantle may form high-density plasma around the outer surface of the outer core, diffuse into the mantle and the crust or return to the core. The relative motion between the electrons and cations produces magnetic field. The magnitude of this magnetic field is direct ratio of their relative velocity. If the geomagnetic field is mainly produced by this way, the relative circular velocity between the ions and the electrons should be ~0.1 (rad/s).