Equatorial Spread F: 'In Situ' Measurements of Electron Density Temperature and Density Fluctuation Power Spectra.
NAVAL RESEARCH LAB WASHINGTON DC
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The NRL pulsed plasma probe experiment was successfully flown on each of the two PLUMEX rockets during July 1979. The experiment provided direct measurements of absolute density Ne, temperature Te and density fluctuation power spectra with a maximum Nyquist frequency of 1 KHz 1 meter resolution at a 1 kmsec rocket velocity. In the first operation, a number of major depletions were distributed throughout the F-region, from its bottomside gradient centered near 260 km, through the F-peak, to a topside altitude of 500 km. The F-peak was at 375 km, with NeMax 11,300,000 cc or - 10. The electron energy distribution was characterized by Te 1350 or - 250K with no obvious signature of energy redistribution in and around the depletions. The most intense in situ irregularities occurred on the bottomside ledge where gradient scale lengths were found to vary between 2 and 25 km. The power spectral density in this region of intense irregularities on the bottomside was dominated by a k-2.5 power law over the intermediate wavelength domain k 2pi1 km to k 2pi2.5 m. This result supports the role of the collisional Rayleigh-Taylor instability in generating intermediate wavelength irregularities during the occurrence of equatorial spread-F.
- Atmospheric Physics