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- Title
Radar Investigation of Postsunset Equatorial Ionospheric Instability Over Kwajalein During Project WINDY.
- Authors
Hysell, D. L.; Rao, S.; Groves, K. M.; Larsen, M. F.
- Abstract
Advanced Research Projects Agency Long‐Range Tracking and Instrumentation Radar (ALTAIR) data acquired during the NASA Waves and INstabilities from a Neutral DYnamo (WINDY) sounding rocket campaign on Kwajalein Atoll in late August and September 2017 are analyzed to study the development of postsunset F‐region ionospheric plasma density irregularities associated with equatorial spread F (ESF) conditions. Unstable conditions existed on nine of ten observing nights during the campaign. The first indication of instability onset each night was a patchy layer of coherent scatter in the bottomside/valley region. Patchy bottom‐type layers are telltales of plasma convective instability driven by vertical current in the F region associated with bottomside shear flow. The resulting flow evolves rapidly into fully developed instability through a bootstrapping process. Sometimes, the resulting topside depletions exhibited large‐scale structuring with a spatial scale too large to be associated with the preferred scale for plasma instability. We examine incoherent scatter observations of the background ionospheric morphology prior to the appearance of bottom‐type layers and find that a small degree of large‐scale bottomside structuring is sometimes present. Numerical simulations suggest that this structuring can act as a seed and provide the initial conditions necessary to account for the clustering of the topside plumes that emerge later. Key Points: Ionospheric interchange instability in the equatorial F region was observed with the ALTAIR radar throughout the NASA WINDY sounding rocket campaignThe radar dataset allows us to distinguish between the "seeding" and "bootstrapping" mechanisms contributing to instabilityVery little ionospheric preconditioning was observed from night to night; what was observed may explain depletion clustering, however
- Subjects
KWAJALEIN Atoll (Marshall Islands); PLASMA instabilities; IONOSPHERIC research; PLASMA density; RADAR research; UNITED States. Advanced Research Projects Agency; SHEAR flow; STATISTICAL bootstrapping
- Publication
Journal of Geophysical Research. Space Physics, 2020, Vol 125, Issue 6, p1
- ISSN
2169-9380
- Publication type
Article
- DOI
10.1029/2020JA027997