The Diamagnetic Layer of the Earth's Atmosphere and Its Relation to The Diurnal Variation of Terrestrial Magnetism
Abstract
Anisotropic conductivity of upper atmosphere due to presence of earth's magnetic field.-An investigation of the motion of ions and electrons in the region of long free paths shows that the electrical conductivity in the direction of the earth's magnetic field is that predicted by simple theory. The conductivity in a direction at right angles to the magnetic field and in the direction of the applied electric field is zero while the pseudo conductivity at right angles to both is finite and the mechanism such that ions of both kinds are swept in the same direction. As a consequence of this situation it appears that large circulating currents in the upper atmosphere of the type assumed in present theories of the diurnal terrestrial magnetic variations are hardly possible. Theory of the diurnal magnetic variation based on diamagnetic effect of ions in upper atmosphere.-A theory of the diurnal magnetic variation is worked out which explains quantitatively the major phenomena in terms of the diamagnetic effect produced by ions spiralling about the earth's magnetic field. The diamagnetic intensity of magnetization of the upper atmosphere in the region of long free paths is found to depend upon the total number of ions of all kinds per cubic centimeter; their mean kinetic energy and the impressed magnetic field. The maximum calculated diurnal magnetic variation as a function of latitude was found to agree in form with observation. The average maximum number of ions of all kinds per cm3 in the upper atmosphere was then computed from observed magnetic data and found to be approximately 5×1010, a number not inconsistent with the ionic density inferred from data derived from radio phenomena.
- Publication:
-
Physical Review
- Pub Date:
- July 1928
- DOI:
- 10.1103/PhysRev.32.133
- Bibcode:
- 1928PhRv...32..133G