EFFECTS OF IONS ON PROPAGATION OF ELF AND VLF WAVES IN LOWER IONOSPHERE

The differential equations governing the propagation of electromagnetic waves in the presence of electrons, positive ions, and negative ions are formulated. These equations are integrated numerically to examine the effects of heavy ions on the propagation of waves of frequency 10 Hz to 30 kHz incident at angles of 30° and 80° on the lower ionosphere. It is found that for an ionospheric model representative of quiet conditions, ions have very little influence on reflection coefficients. Significant effects are, however, found for a model representing a disturbed ionosphere, especially at the higher frequencies. An examination of the standing wave-field patterns set up in the ionosphere helps in the interpretation of these effects. © 1969.