The Auroral Energy Deposition Over the Polar Ionosphere during Substorms
Abstract
The global Joule heating distributions are estimated through the magnetogram inversion method. This study employs instantaneous ionospheric conductance distributions deduced from the DMSP-F6 bremsstrahlung Xray image data. Also estimated from the Xray data are instantaneous global particle heating distributions. The two heating distributions thus obtained allow us to investigate various aspects of heat energy processes over the polar ionosphere on an instantaneous basis. A special emphasis is placed on their spatial and temporal behaviors. Several important results of this study are summarized as follows: (1) Regions of significant Joule heating are closely associated with the auroral electrojets prominently in the dawn and dusk sectors. (2) The major Joule heating usually occurs poleward of the major particle heating region, particularly in the morning sector. On the other hand, the two heating patterns are complementary in the longitudinal direction. (3) There is a higher correlation between the global Joule heating rate (U Sub J) and AE(12) than between the global particle heating rate (U Sub A) and AE(12). (4) The particle heating rate tends to be more prominent during the maximum phase of substorms and afterward than during the pre-expansion phase. (5) The U Sub J/U Sub A ratio varies by more than a factor of 10, suggesting the wide variability in the relative importance of the two heating rates. On the average, however, U Sub J is larger than U Sub A by a factor of 6.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 15, 1989
- Accession Number
- ADA210522
Entities
People
- B.-h. Ahn
- D. J. Gorney
- H. W. Kroehl
- J. R. Kan
- S.-i. Akasofu
- Y. Kamide
Organizations
- The Aerospace Corporation