Coherence scales of wavefield during propagation through naturally disturbed ionosphere in the polar cap, auroral, and equatorial regions

Technical Report · Thu May 03 04:00:00 EDT 1990

OSTI ID:6193453

Basu, S; Basu, S; Livingston, R C

Phase and intensity scintillation measurements have been made at low latitudes in the equatorial anomaly region, and at high latitudes in the auroral oval and the polar cap regions, using phase coherent transmissions at 250 MHz from stationary and near stationary satellites. The observations pertain to periods of high solar activity when intense scintillation activity is recorded at each of the above observing sites. This data set has been utilized to study the reduction of coherence times of intensity and complex amplitude scintillation with increasing strength of scattering. Estimates of coherence scales of intensity and complex amplitude scintillation at 250 MHz are provided which indicate that coherent scales of scintillation are typically of the order of hundreds of meters at high latitudes but approach values as small as tens of meters in the equatorial anomaly region. The phase spectral index in the nightside auroral oval is observed to be much steeper (p sub psi = .4) than those typically observed in the equatorial (p sub psi = 2.4) or polar cap regions (p sub psi approx. -2.3). It shows the importance of large scale phase variations in the nightside auroral oval. Under strong scatter conditions, the coherence times of complex amplitude scintillation are shown to asymptotically approach a value which is 1.4 times the coherence time of intensity scintillation. This result is consistent with the theoretical predictions for Rayleigh statistics.

• Research Organization: Air Force Geophysics Lab., Hanscom AFB, MA (United States)
• OSTI ID: 6193453
• Report Number(s): AD-P-006278/6/XAB
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAL OVAL
COMPARATIVE EVALUATIONS
DISTURBANCES
EARTH ATMOSPHERE
EQUATOR
EVALUATION
GLOBAL ASPECTS
IONOSPHERE
PHASE SHIFT
PLANETARY IONOSPHERES
POLAR REGIONS
SCINTILLATIONS
SOLAR ACTIVITY
TROPICAL REGIONS
WAVE PROPAGATION