Accession Number : AD0767303

Title :   Ionospheric Research Using Satellites - The Equatorial Faraday Evening Minimum.

Descriptive Note : Interim scientific rept. 1 Jan-31 Dec 72,

Corporate Author : GHANA UNIV LEGON DEPT OF PHYSICS

Personal Author(s) : Koster,John R.

Report Date : 01 FEB 1973

Pagination or Media Count : 63

Abstract : A deep daily minimum in total electron content occurs a few hours after local sunset at Legon on most days during eight months of the year. This minimum can be explained in terms of an elliptical motion of ionization in the vertical E-W plane over the equator. It is suggested that the motion is caused by an electrostatic field, mapped into the F region along field lines from the dynamo region. The field is thought to be due to an accumulation of negative charge in a band just east of the sunset line in the E region. The mechanism described by Carlson and Walker (1972) is suggested as the cause for the field. The electrostatic field and its accompanying elliptical circulation moves westward with the speed of the sunset line (490 m/s). A computer model based on this mechanism produces results comparable with those obtained experimentally. The production of irregularities giving rise to spread F and scintillation is closely associated with this elliptical circulation. (Author)

Descriptors :   (*IONOSPHERIC DISTURBANCES, IONIZATION), (*IONOSPHERIC PROPAGATION, SCINTILLATION), RADIO TRANSMISSION, ELECTROSTATIC FIELDS, ELECTRON DENSITY, MATHEMATICAL MODELS

Subject Categories : Atmospheric Physics
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE