Weakly attenuated 100 Hz waves. Moderately attenuated 100 Hz waves. This amplitude is the sum of both incident and reflected waves. We find that the waves do deposit energy into the ionosphere, but only at very low altitudes, where the density is low. Any analysis of the importance of Joule dissipation in the ionosphere of Venus must include electron heat conduction.
Heat conduction is much more effective in balancing the energy input from Joule dissipation.
Collisional Joule dissipation of lightning generated VLF signals could heat the bottomside ionosphere. However, the heating rate is small, and can be balanced through heat conduction. Joule dissipation does not preclude a lightning source for the VLF bursts in the nightside ionosphere of Venus. Collisional Joule dissipation does not preclude a lightning source for these waves. Addendum Through conversations with Walt Hoegy, Tom Cravens, and Jane Fox at the Fall AGU Meeting, it has become clear that the neutral atmosphere can cool electrons very efficiently.