The eleven year solar cyc
The eleven year solar cycle of the sun affects the frequency of waves that can be reflected off this layer of the atmosphere. This layer contains the F1 and F2 layers, which combine into the Appleton layer at night, due to the lack of sunlight acting on the entities that compose this layer. The E layer of this layer of the atmosphere can cause hops in radio signals, and solar radiation produces free electrons which make up this layer. For 10 points, name this layer of the atmosphere that is part of the thermosphere, named after the charged particles that compose it.
The eleven year solar cycle of the sun affects the frequency of waves that can be reflected off this layer of the atmosphere.
Ionosphere [prompt on Thermosphere]