Statistical and functional representations of the pattern of auroral energy flux, number flux, and conductivity

Technical Report · Sun Nov 01 04:00:00 EST 1987

OSTI ID:6907765

Hardy, D A; Gussenhoven, M S; Raistrick, R

Global patterns of the integral energy flux and average energy of precipitating auroral electrons are used to determine the global pattern of the electron-produced, height-integrated Hall and Pedersen conductivities. The conductivities were determined in spatial bins in magnetic local time (MLT)-corrected geomagnetic latitude (CGL) coordinates for all MLTs and for CGLs greater than 50 deg and for seven levels of activity as measured by Kp. On the nightside the two conductivities increase with increasing Kp. The largest conductivities are found near midnight, where the peak value of the Pedersen (Hall) conductivity varies from 3.09 (4.05) mhos to 12.5 (25.9) mhos as Kp varies from 0 > or = 6-. At noon and on much of morning side of the oval the Pedersen and Hall conductivities increase for Kp up to 2 and then decrease for higher Kp. The highest ratios of the Hall to Pedersen conductivity are on the morning side of the oval and at noon. The peak conductivities on the dayside are significant compared to the conductivities produced by solar radiation at all seasons of the year. The global maps of the integral energy flux, integral number flux, and height-integrated Hall and Pedersen conductivities at each level of Kp were fit using both spherical harmonic and Epstein functions. The Epstein functions were found to reproduce better the original maps. At Kp = 2 the distribution of differences between the Epstein function fit and the original data is roughly symmetric about zero with a full width at half maximum of 16 (20)% for the Pedersen (Hall) conductivity and 32(40)% for the integral energy (number) flux. The distribution of difference broadens with increasing and decreasing activity.

• Research Organization: Air Force Geophysics Lab., Hanscom AFB, MA (USA)
• OSTI ID: 6907765
• Report Number(s): AD-A-193886/9/XAB; AFGL-TR-88-0074
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
CHARGED-PARTICLE PRECIPITATION
COORDINATES
CORRECTIONS
ELECTRON PRECIPITATION
ENERGY DENSITY
FUNCTIONS
GEOMAGNETIC COORDINATES
HALL EFFECT
HARMONICS
MAGNETIC FIELDS
MAPS
MATHEMATICS
OSCILLATIONS
RADIATIONS
SOLAR RADIATION
STATISTICS
STELLAR RADIATION