How is the Ionosphere Formed?
At the outer reaches of the Earth’s environment, solar radiation strikes the atmosphere with a power density of 1370 Watts per meter2 or 0.137 Watts per cm2, a value known as the “solar constant.” This intense level of radiation is spread over a broad spectrum ranging from radio frequencies through infrared (IR) radiation and visible light to X-rays. Solar radiation at ultraviolet (UV) and shorter wavelengths is considered to be “ionizing” since photons of energy at these frequencies are capable of dislodging an electron from a neutral gas atom or molecule during a collision. The conceptual drawing below is a simplified explanation of this process. Ionization Process Incoming solar radiation is incident on a gas atom (or molecule). In the process, part of this radiation is absorbed by the atom and a free electron and a positively charged ion are produced.
