Geospace Plasma Dynamics: Final Report (2002-2007)
Abstract
Radar measurements of backscatter from plumes extending above the bottom side spread-F layer correlated well with observations of equatorial plasma bubbles in quiet conditions with lower correlation between scintillation and observations of plasma bubbles. DMSP satellites and the ROCSAT-1 satellite showed significantly fewer occurrences of plasma bubbles than expected near the west coast of South America and an east-west chain of GPS receivers confirms a steep longitudinal gradient in EPB occurrence rate. A statistical database of equatorial plasma bubbles bas been compiled. Observations of transient sheets of field-aligned currents observed by DMSP during the main phase magnetic superstorm showed that under some highly stressed conditions contributions from low energy electrons and precipitating ions contribute significantly to Pedersen conductances. We developed a new fluid theory for the auroral return-current region in the guiding-center and gyrotropic approximation and used in calculations of the turbulent beating rate for magnetospheric ions in downward Birkeland Current regions. We compared different theoretical descriptions of linear equatorial plasma instabilities, and showed that the ballooning mode description gives a physically more accurate and complete description and thus should be adopted for calculating linear growth rates. Our study of the unstable Rayleigh-Taylor plasma modes in the equatorial ionosphere has shown that the magnetic field fluctuations are associated with the shear Alfven waves, and that the electrostatic assumption is usually justified. Assimilating the vertical drift of the plasma after sunset can improve forecasts of equatorial radio scintillation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 14, 2007
- Accession Number
- ADA473140
Entities
People
- Bamandas Basu
- John R. Jasperse
Organizations
- Air Force Research Laboratory