(n) A region of this earth's environment in which ionization due to incoming solar radiation impacts the transmission of radio waves. It expands from a height of 70 kilometers (43 miles) to 400 kilometers (250 miles) over the surface.
(n) The an element of the Earth's environment beginning at an altitude of approximately 50 kilometers (31 kilometers) and extending outward 500 kilometers (310 kilometers) or higher.
(n) The comparable area of the environment of another world.
Ionosphere in Astronomy Dictionary
the region of Earth's upper atmosphere containing half the normal commission of free electrons and ions produced by photoionization of this constituents associated with atmosphere by solar power ultraviolet radiation. The ionosphere dramatically affects radiowave propagation of frequencies lower than about 30 MHz. In Earth's atmosphere, the ionosphere starts at an altitude around 25 miles and stretches outward about 250. by Pearlie ParnellReport definition