Steepened structures in equatorial spread F: 1. New observations
- Cornell Univ., Ithaca, NY (United States); and others
Sounding rocket data from the 1990 CRRES/EQUIS equatorial spread F campaign on Kwajalein Atoll are presented. Two Terrier Malamute sounding rockets were launched into active spread F conditions on July 30 and August 2, respectively, and achieved apogee slightly below 500 km, just above the F peak. Plasma frequency probes aboard both rockets showed that the unstable nighttime F region is characterized by propagating steepened structures. Power density spectra for the structures typically exhibit two regions that obey k{sup {minus}n} scaling, where n is approximately equal to 2 at wavelengths greater than 80-100 m and approximately equal to 5 at shorter wavelengths. These spectral indices are quite variable, and the long-wavelength spectral index in particular seems to decrease with increasing amplitude of density fluctuations. The rocket payloads also measured vector electric fields in the plane perpendicular to B over wavelengths ranging from over 60 km to less than 6 m. Both vector components of the perpendicular electric field are proportional to {delta}n/n at wavelengths longer than 300 m but assume a Boltzmann relationship (with {vert_bar}{delta}E{vert_bar}{sup 2} {approximately} k{sup 2}{vert_bar}{delta}n/n{vert_bar}{sup 2}) at smaller scales. The perturbed zonal electric field, {delta}E{sub x}, dominates the vertical field, {delta}E{sub z}, at long wavelengths, but the situation is reversed at smaller scales. 25 refs., 7 figs.
- OSTI ID:
- 255693
- Journal Information:
- Journal of Geophysical Research, Vol. 99, Issue A5; Other Information: PBD: 1 May 1994
- Country of Publication:
- United States
- Language:
- English
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