Premium
Vertical‐10 rocket measurements of mid‐latitude, nighttime F region irregularities
Author(s) -
Wernik A. W.,
Natorf L.,
Gdalevich G. L.,
Ozerov V. D.
Publication year - 1986
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/rs021i006p01021
Subject(s) - ionosphere , plasmasphere , f region , physics , spectral index , rocket (weapon) , geophysics , plasma , spectral line , amplitude , geology , atmospheric sciences , magnetosphere , optics , astronomy , engineering , aerospace engineering , quantum mechanics
The results of a rocket experiment carried out in the mid‐latitude, nighttime ionosphere revealed an isolated plasma density depletion between 700 and 1100 km. A substantial enhancement of intensity of irregularities coinciding with the depletion was observed over a broad band of irregularity sizes from tens of meters to several hundred kilometers. The power spectra of irregularities show a break in slope occurring at irregularity size 10–15 km. At larger sizes the spectrum is very steep with the spectral index close to 4. Smaller irregularities have a shallow slope, and the spectral index is close to 1. No correlation between the spectral index and irregularity amplitude is found. It is suggested that the plasma depletion and large‐scale irregularities are slow mode hydromagnetic waves stimulated by gravity waves in the lower atmosphere and propagating along magnetic field lines. Medium‐scale irregularities observed inside the depletion could be produced by theE ¯ × B ¯gradient drift instability mechanism. Steep spectrum, however, indicates that the nonlinear evolution of the mid‐latitude, topside irregularities can be quite different from those in other regions of the ionosphere. A potential production mechanism of small‐scale irregularities could involve a high velocity stream of cold plasma from the plasmasphere to the ionosphere, as indeed observed in our experiment.