Magnetospheric Structure and Dynamics: A Multisatellite Approach
Abstract
This report reviews progress during the first year of a contract to study magnetospheric structure and dynamics. Four areas of scientific investigation are highlighted. Pressure gradients form in the geotail because ions drift preferentially toward the dusk flank. These pressure gradients drive field aligned currents that close in the ionosphere and which provide a natural explanation of the Harang discontinuity when the full electrodynamics are modelled. Observations made during a passage by DE 2 through the dayside cusp at a time when the IMF was directed northwards are consistent with magnetic merging occurring on field line that map to the poleward cusp boundary. We infer that tail lobe field lines were merging with magnetosheath field lines at the magnetopause tailward of the external cusp. During the March 1989 magnetic storm, the DMSP F9 spacecraft observed extensive substantial decreases in equatorial ion density in the post-dusk sector. Modelling calculations show that the depletions were caused by unusually large upward flows moving the equatorial F region peak above 850 km. Calculations of ion cyclotron wave group velocities show that they are sensitive to both the hot and cold plasma populations. Calculated group delays agree with our earlier observations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 20, 1991
- Accession Number
- ADA237674
Entities
People
- W. J. Hughes
Organizations
- Boston University