Man-Made Heating and Ionization of the Upper Atmosphere

Absorption of radio signals by cyclotron resonance is shown to be possible within a very narrow layer of the atmosphere (20 km thick just below 100 km). For a plane-polarized signal only 25% of the power can be absorbed. Better results are obtained (50%) with a circularly polarized radio wave. The absorbable power is limited by the effects obtained so that an electron density of 3000 cm−3 and an electron temperature of 1600°K cannot be exceeded. The reason for this is the weakness of the earth's magnetic field.