Submitting Campus

Daytona Beach

Department

Physical Sciences

Document Type

Article

Publication/Presentation Date

2005

Abstract/Description

An investigation into the dynamics and layer structure of the postsunset ionosphere prior to the onset of equatorial spread F (ESF) took place during the NASA EQUIS II campaign on Kwajalein Atoll on August 7 and 15, 2004. On both nights, an instrumented rocket measured plasma number density and vector electric fields to an apogee of about 450 km. Two chemical release rockets were launched both nights to measure lower thermospheric wind profiles. The Altair UHF/VHF radar was used to monitor coherent and incoherent scatter. In both experiments, strong plasma shear flow was detected. Periodic, patchy bottom-type scattering layers were observed in the westward-drifting plasma below the shear nodes. The large-scale plasma depletions that formed later during ESF reproduced the periodic structure of the original, precursor layers. The layers were therefore predictive of the ESF that followed. We surmise that collisional shear instabilities may have given rise to large-scale plasma waves that were highlighted by the bottom- type layer structure and that preconditioned the postsunset ionosphere for ESF.

Publication Title

Geophysical Research Letters

DOI

https://doi.org/10.1029/2005GL024743

Publisher

American Geophysical Union

Grant or Award Name

NASA grants NAG5-5380, NAG5-5373, and NAG5-5379

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