Effect of day-night inhomogeneity on elf fields

The extra-low-frequency fields in the earth-ionosphere resonator are computed in the presence of the day-night ionospheric inhomogeneity. It is shown that the presence of the inhomogeneity leads to significant changes in the field in the neighborhood of the node line of the first mode of elf oscillations, to curving of the level line of the field, and to reversion of the node line of the first mode into a single node