The Ionosphere

So, what’s up there?

But what is the ionosphere? What is up there and how does it reflect, refract, or scatter radio waves? Are ions the big thing, or is there something more subtle going on? And why does the ionosphere behave as it does, sometimes supporting propagation for days or only supporting an opening for minutes? Here’s the answer.

Ionosphere structure

The Sun causes the gases of the ionosphere to ionise. The degree of ionisation and the resulting electric charge density differ with height. Molecules higher up and closer to the Sun get cooked more, and hence produce more ions. In the end, it’s all about charge density. Here’s a description of the ionosphere that will aid understanding.