Accession Number : ADA130889

Title :   High-Latitude F-Region Irregularities: Intensity and Scale Size Distributions.

Descriptive Note : Memorandum rept.,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON DC

Personal Author(s) : Rodriguez,P ; Szuszczewicz,E P

PDF Url : ADA130889

Report Date : 21 Jul 1983

Pagination or Media Count : 55

Abstract : A broad range of lower F-region irregularity scale sizes (150 km L 75m) at high northern latitudes during the spring and summer of 1978 has been studied. The morphology and intensity distribution of the iregularities shows that particle precipitation in the auroral oval and polar cusp are the primary agents in driving density fluctuations. The most intense density fluctuations observed under moderately active geomagnetic conditions occur in the polar cusp, where small scale irregularities are particularly prominent. Absolute density enhancements approaching 10 to the 6th power 3/cm have been observed in the polar cusp. Auroral oval irregularities have absolute density enhancements generally less than the polar cusp enhancements, with maximum values of about 8 x 0,00001 3/cm. Large density enhancements within the polar cap have been detected principally toward the duskward side. These polar cap enhancements are similar to auroral oval enhancements, thus suggesting that polar cap precipitation is the source of the density fluctuations. A region of density depletion with respect to the background photoionization is found toward the dawnward side of the polar cap. Such relative depletions may arise from the joint action of lower F-region recombination rates and enhanced cross-field diffusion. In general, the overall two-cell convection pattern at high latitudes has a minimal effect in the redistribution of precipitation-induced irregularities.

Descriptors :   *F region, *High latitudes, *Geomagnetism, Intensity, Scale, Sizes(Dimensions), Morphology, Polar cap, Particle size, Electron density, Aurorae, Density, Variations

Subject Categories : Atmospheric Physics
      Geomagnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE