F region

Appleton - layer, also known as F- layer, a part of the earth's ionosphere. It is the highest of the layers of the ionosphere where shortwave radio signals are reflected and therefore plays the most important role in the spread of the sky wave radio signals. The Appleton layer was named after the British physicist Edward Victor Appleton.

The F layer is divided into layers F1 and F2. The lower F1 layer ranges from 150 to 220 km altitude and is only available during the day. It consists of a mixture of positively charged O2 and NO ions and atomic oxygen O . The F2 layer spreads over the F1 layer, which primarily consists of positively charged , atomic oxygen O. The F2 layer is located at a height 220-800 km.

The F1 layer has at lunchtime at minimum solar activity approximately 5 × 105 free electrons per cm3 on. Increased solar activity in the charge carrier density can reach values ​​of up to 2 x 106 per cm3. At night, the electron density of the F1 - layer falls to values ​​below 104 electrons per cm3.

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