Working Draft Framework, Version 2, June 4, 1996
Definition Source: Satellite Environment Handbook
1.2.5.2.1 D Region: The lowest layer of the ionosphere extending from approximately 60-85 km and dominated by NO+ ions generated by apsorption of Lyman-Alpha radiation. The D Region disappears at night. (Definition Source: Satellite Environment Handbook)
1.2.5.2.2 E Region: The layer of the ionosphere extending from approximately 85-140 km and dominated by O2+ and NO+ ions generated by the absorption of soft X-rays. (Definition Source: Satellite Environment Handbook)
1.2.5.2.3 F1 Region: The layer of the ionosphere extending from approximately 140-200 km and dominated by O2+ and NO+ ions at the lower boundry and transitioning to O+ at the upper boundry. Absorption by radiation between 200-900 angstroms generate the F1 layer. The F1 layer disappears completely at night.. (Definition Source: Satellite Environment Handbook)
1.2.5.2.4 F2 Region: The layer of the ionosphere extending from approximately 200-1000 km and dominated by O+ and some N+ ions. Ion density peaks between 200-400 km and then slowly tapers off. Unlike the F1 layer, the F2 layer does not disappear at night.. (Definition Source: Satellite Environment Handbook)