Condor equatorial Spread F campaign. Overview and results of the large-scale measurements
During the Condor campaign a number of instruments were set up in Peru to support the rocket experiments. This overview paper summarizes the main results on the macroscopic developments of spread F as evidenced by data from backscatter radars, from scintillation observations, and from digital ionosonde measurements. In this regard, at least two factors other than the classical gravitational Rayleigh-Taylor plasma instability process must operate to yield the longest scales horizontal organization of spread F structures. The horizontal scale typical of plume separation distances can be explained by invoking the effect of a shear in the plasma flow, although detailed comparison with theory seems to require shear frequencies a bit higher than observations indicate. On the other hand, the largest-scale organization or modulation of the scattering layer cannot be explained by the shear theory and must be due to local time variations in the ionospheric drift or to gravity wave induced vertical motions. Using simultaneous rocket and radar data, it is hypothesized that rapid overhead height variations in the scattering region over Jicamarca are primarily spatial structures advecting overhead. The detailed rocket-radar comparison verified several other earlier results and speculations, particularly those made in the PLUMEX experiments.
- Research Organization:
- Air Force Geophysics Lab., Hanscom AFB, MA (USA)
- OSTI ID:
- 6961100
- Report Number(s):
- AD-A-174216/2/XAB; AFGL-TR-86-0229
- Country of Publication:
- United States
- Language:
- English
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