Accession Number : ADA193200

Title :   The Low-Latitude Auroral Boundary: Steady-State and Time-Dependent Representations.

Descriptive Note : Technical rept.,

Corporate Author : AEROSPACE CORP EL SEGUNDO CA SPACE SCIENCES LAB

Personal Author(s) : Gorney, D J ; Evans, D S

PDF Url : ADA193200

Report Date : 25 Mar 1988

Pagination or Media Count : 32

Abstract : Recently, extensive data sets have been acquired from charged-particle detectors on low-altitude satellites pertinent to the study of the low-latitude boundary of the aurora, including both case studies and statistical treatments. The low latitude auroral boundary can be thought of as the low-altitude manifestation of convection boundaries for magnetospheric particles of moderate energy, although the detailed shape of the boundary might be modified locally by spatial variations or temporal modulation of precipitation rates. Several attempts have been made to compare observed equatorial and low-altitude boundaries with theoretical representations, with varying degrees of success. Here, the results of statistical analysis and case studies of the auroral boundary using precipitating particle data acquired by the NOAA spacecraft are presented. The ability of standard convection models to account for the observed boundary characteristics is discussed, with emphasis on the roles of convection strength and time dependence. It is demonstrated that, within reasonable parameter limits, steady-state convection patterns for moderate energy electrons generally fail to account for certain observed characteristics of boundary shapes. Keywords: Aurora, Magnetospheric particles, Magnetospheric activity.

Descriptors :   *AURORAE, ARTIFICIAL SATELLITES, BOUNDARIES, CASE STUDIES, CHARGED PARTICLES, DATA BASES, DETECTORS, ELECTRONS, ENERGY, LIMITATIONS, LOW ALTITUDE, MAGNETOSPHERE, MODELS, PARAMETERS, PARTICLES, PATTERNS, PRECIPITATION, RATES, SHAPE, SPACECRAFT, SPATIAL DISTRIBUTION, STATISTICAL ANALYSIS, STEADY STATE, STRENGTH(GENERAL), TIME DEPENDENCE, ARCTIC REGIONS, CONVECTION(ATMOSPHERIC)

Subject Categories : Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE