Observations of the Generation of Eastward Equatorial Electric Fields near Dawn

DSpace/Manakin Repository

Observations of the Generation of Eastward Equatorial Electric Fields near Dawn

Show full item record

Title: Observations of the Generation of Eastward Equatorial Electric Fields near Dawn
Author(s):
Kelley, M. C.;
Rodrigues, Fabiano S. (UT Dallas);
Pfaff, R. F.;
Klenzing, J.
Sponsors: William B. Hanson Center for Space Sciences
Item Type: Article
Keywords: Show Keywords
Abstract: We report and discuss interesting observations of the variability of electric fields and ionospheric densities near sunrise in the equatorial ionosphere made by instruments onboard the Communications/Navigation Outage Forecasting System (C/NOFS) satellite over six consecutive orbits. Electric field measurements were made by the Vector Electric Field Instrument (VEFI), and ionospheric plasma densities were measured by Planar Langmuir Probe (PLP). The data were obtained on 17 June 2008, a period of solar minimum conditions. Deep depletions in the equatorial plasma density were observed just before sunrise on three orbits, for which one of these depletions was accompanied by a very large eastward electric field associated with the density depletion, as previously described by de La Beaujardiere et al. (2009), Su et al. (2009) and Burke et al. (2009). The origin of this large eastward field (positive upward/meridional drift), which occurred when that component of the field is usually small and westward, is thought to be due to a large-scale Rayleigh-Taylor process. On three subsequent orbits, however, a distinctly different, second type of relationship between the electric field and plasma density near dawn was observed. Enhancements of the eastward electric field were also detected, one of them peaking around 3 mV m⁻¹, but they were found to the east (later local time) of pre-dawn density perturbations. These observations represent sunrise enhancements of vertical drifts accompanied by eastward drifts such as those observed by the San Marco satellite (Aggson et al., 1995). Like the San Marco measurements, the enhancements occurred during winter solstice and low solar flux conditions in the Pacific longitude sector. While the evening equatorial ionosphere is believed to present the most dramatic examples of variability, our observations exemplify that the dawn sector can be highly variable as well.
Publisher: Copernicus Gesellschaft Mbh
ISSN: 0992-7689
Persistent Link: http://hdl.handle.net/10735.1/4249
http://dx.doi.org/10.5194/angeo-32-1169-2014
Terms of Use: CC-BY 3.0 (Attribution)
Sponsors: US National Science Foundation (no. ATM-0551107; AGS-1261107)

Files in this item

Files Size Format View
CSS-SR-FSRodrigues-271569.65.pdf 1.548Mb PDF View/Open Article

This item appears in the following Collection(s)


Show full item record

CC-BY 3.0 (Attribution) Except where otherwise noted, this item's license is described as CC-BY 3.0 (Attribution)