Accession Number:
ADA275442
Title:
Space-Time Structure of the Morning Aurora Inferred from Coincident DMSP-F6, -F8, and Sondrestrom Incoherent Scatter Radar Observations
Descriptive Note:
Corporate Author:
AEROSPACE CORP EL SEGUNDO CA TECHNOLOGY OPERATIONS
Personal Author(s):
Report Date:
1993-10-01
Pagination or Media Count:
16.0
Abstract:
On rare occasions, observations from the DMSP-F6 and -F8 spacecraft and the Sondrestrom incoherent scatter radar coincide in space. Such coincidence offers a unique opportunity to study temporal vs spatial variations on a small scale. We discuss data from one of those occasions, with observations made in the dawn sector in the presence of moderate auroral precipitation during a magnetically quiet period. The DMSP satellites measured vertical electron and ion flux and cross-track plasma drift while the radar measured the ionospheric electron density distribution and line-of-sight plasma velocities. We combine these data sets to construct a two-dimensional map of a possible auroral pattern above Sondrestrom. It is characterized by the following properties. No difference is seen between the gross precipitation patterns measured along the DMSP-F6 and -F8 trajectories separated by 32 km in magnetic east-west direction and some 4 s in travel time in magnetic north-south direction, except that they are not exactly aligned with the L shells. However, F6 and F8 observed minor differences in the small-scale structures. More significant differences are found between small-scale features in the DMSP precipitation measurements and in radar observations of the Enregion plasma density distribution. These measurements are separated by 74 km, equivalent to 2.4 deg, in magnetic longitude, and 0-40 s in time along the spacecraft trajectories varying with magnetic latitude. Large-scale magnetospheric-ionospheric surfaces such as plasma flow reversal, poleward boundary of the keV ion and electron precipitation, and poleward boundary of E-region ionization, coincide. Aurora, DMSP, Particle precipitation.
Descriptors:
- *ATMOSPHERIC SCATTERING
- *METEOROLOGICAL RADAR
- *AURORAE
- VELOCITY
- LINE OF SIGHT
- IONS
- DENSITY
- MEASUREMENT
- MAGNETIC FIELDS
- SPACECRAFT
- MAPS
- IONIZATION
- ARTIFICIAL SATELLITES
- PARTICLES
- DRIFT
- PRECIPITATION
- ELECTRONS
- VARIATIONS
- METEOROLOGICAL SATELLITES
- LONGITUDE
- LATITUDE
- TRAVEL TIME
- E REGION
- SPACECRAFT TRAJECTORIES
- POLAR CAP
- TRAJECTORIES
- INCOHERENT SCATTERING
- TWO DIMENSIONAL
- PLASMAS(PHYSICS)
- ELECTRON DENSITY
- OBSERVATION
- BOUNDARY LAYER
- ELECTRIC FIELDS
- RADAR
Subject Categories:
- Atmospheric Physics
- Active and Passive Radar Detection and Equipment