Then how would you explain Venus' lack of a strong magnetic field?
In the model, which apparently physics rebel RightWhale is the only one to have thought of, there must be an atmosphere, but it must also be rotating to produce the characteristic magnetic field. It might be that the atmosphere must also contain components that respond to nuclear magnetic resonance fields. Water vapor is one such component. One may experiment with various materials in the kitchen by putting various materials in the microwave oven. Those that are warmed by the microwaves may have the ability to generate magnetic fields in an atmosphere. In some cases the spousal unit may discourage such basic experimental science. Venus' atmosphere does not appear to be rotating vigorously.