Appleton layer, F layer, F region(noun)
the highest region of the ionosphere (from 90 to 600 miles up) which contains the highest concentration of free electrons and is most useful for long-range radio transmission
The F region of the ionosphere is home to the F layer of ionization, also called the Appleton layer, after the English physicist Edward Appleton. As with other ionospheric sectors, 'layer' implies a concentration of plasma, while 'region' is the area that contains the said layer. The F region contains ionized gases at a height of around 150–800 km above sea level, placing it in the Earth’s thermosphere, a hot region in the upper atmosphere, and also in the heterosphere, where chemical composition varies with height. Generally speaking, the F region has the highest concentration of free electrons and ions anywhere in the atmosphere. It may be thought of as comprising two layers, the F1-and F2-layers. The F-region is located directly above the E region and below the protonosphere. It acts as a dependable reflector of radio signals as it is not affected by atmospheric conditions, although its ionic composition varies with the sunspot cycle. It reflects normal-incident frequencies at or below the critical frequency and partially absorbs waves of higher frequency. The F region is the region of the ionosphere which is very important for HF radio wave propagation. This F region is very anomalous in nature.
The numerical value of f region in Chaldean Numerology is: 4
The numerical value of f region in Pythagorean Numerology is: 2
Sample Sentences & Example Usage
Every nation in every region now has a decision to make. Either you are with us, or you are with the terrorists.
Mathematics takes us into the region of absolute necessity, to which not only the actual word, but every possible word, must conform.
America lives in the heart of every man everywhere who wishes to find a region where he will be free to work out his destiny as he chooses.
Japan would like to work with the countries of the Mekong region to create a framework to support efforts by the Mekong countries in a detailed manner, on a region-by-region basis or on a theme-by-theme basis.
Freedom of navigation in this region, through the South China Sea, is crucial for any further development in the region and it's difficult to imagine that without this freedom, there will be stability and peace in this region.
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