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Auroral zone electric fields from DE 1 and 2 at magnetic conjunctionsNearly simultaneous measurements of auroral zone electric fields are obtained by the Dynamics Explorer spacecraft at altitudes below 900 km and above 4,500 km during magnetic conjunctions. The measured electric fields are usually perpendicular to the magnetic field lines. The north-south meridional electric fields are projected to a common altitude by a mapping function which accounts for the convergence of the magnetic field lines. When plotted as a function of invariant latitude, graphs of the projected electric fields measured by both DE-1 and DE-2 show that the large-scale electric field is the same at both altitudes, as expected. Superimposed on the large-scale fields, however, are small-scale features with wavelengths less than 100 km which are larger in magnitude at the higher altitude. Fourier transforms of the electric fields show that the magnitudes depend on wavelength. Outside of the auroral zone the electric field spectrums are nearly identical. But within the auroral zone the high and low altitude electric fields have a ratio which increases with the reciprocal of the wavelength. The small-scale electric field variations are associated with field-aligned currents. These currents are measured with both a plasma instrument and magnetometer on DE-1.
Document ID
19850062284
Document Type
Reprint (Version printed in journal)
Authors
Weimer, D. R. (Iowa Univ. Iowa City, IA, United States)
Goertz, C. K. (Iowa Univ. Iowa City, IA, United States)
Gurnett, D. A. (Iowa, University Iowa City, United States)
Maynard, N. C. (USAF, Geophysics Laboratory, Bedford MA, United States)
Burch, J. L. (Southwest Research Institute San Antonio, TX, United States)
Date Acquired
August 12, 2013
Publication Date
August 1, 1985
Publication Information
Publication: Journal of Geophysical Research
Volume: 90
ISSN: 0148-0227
Subject Category
GEOPHYSICS
Funding Number(s)
CONTRACT_GRANT: NGL-16-001-043
CONTRACT_GRANT: NGL-16-001-002
CONTRACT_GRANT: NAS5-26363
CONTRACT_GRANT: NAS5-25693
CONTRACT_GRANT: NAS5-25694
CONTRACT_GRANT: N00014-76-C-0016
CONTRACT_GRANT: NAG5-310
Distribution Limits
Public
Copyright
Other