The "ionosphere" is the electrically charged region of the upper atmosphere above about 85 km altitude that is produced by the ionizing action of solar ultraviolet and X rays of wavelength shorter than about 100 angstroms. The ionosphere is important for communications in that it reflects radio and radar wavelengths longer than a few meters wavelength, and scatters and refracts shorter wavelengths. Much interference in both long and short wavelength radio communication, and for ground to satellite communcation, is produced by waves and irregularities in the ionosphere. This award is directed to studies of the ionosphere, and especially of the mechanisms giving rise to ionospheric irregularities, both at equatorial regions and at high latitudes.
