Average Low-Latitude Meridional Electric Fields from DE 2 during Solar Maximum
Abstract
Electric field data from the double probe vector electric field instrument (VEFI) on the DE 2 spacecraft have been analyzed to determine the average meridional electric field (zonal ion flow) patterns in the region between + or - 30 deg magnetic latitude during solar maximum conditions. Over 300 passes were used to compile the data set. Data were projected to a constant 300-km altitude and to the equatorial plane assuming that the electric field along the magnetic field was zero. The average data set displayed a rapid increase of the downward meridional electric field with local time near 1800 MLT with the higher latitudes seeing the change first. A secondary nighttime maximum of this electric field component was observed past midnight with the crossover to upward electric fields (westward ion flow) occurring between 0400 and 0500 MLT. A sharp return to near zero was observed between 1200 and 1300. Typical average amplitudes range between 3 and 6 mV/m. No consistent variations with magnetic activity were observed. Although the daily variation in the zonal ion flow is dominated by the diurnal term, a net superrotation is evident in the harmonic analysis. The superrotation is strongest near the equator and decreases with latitude, because of the disturbance dynamo. The higher order harmonics up through the quatrediurnal term are also of significant magnitude in the anslysis of the shape of the daily variation. Close similarity is seen to the zonal neutral winds indicating that they form the principal driving force. The magnitudes of the electric field derived ion drift are somewhat higher than the average F region neutral wind values. Reprints.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 07, 1988
- Accession Number
- ADA200338
Entities
People
- F.a. Herrero
- M.c. Liebrecht
- N.c. Maynard
- T.l. Aggson
Organizations
- Air Force Research Laboratory