In this paper the weak scatter scintillation theory is reformulated to show explicitly ramifications of an arbitrarily large ionospheric outer scale. The measured temporal phase spectrum, for example, effectively truncated at a fixed frequency corresponding detrend time or length data interval over which it (whichever smaller). As consequence, rms exhibits complicated dependence on relative irregularity drift velocity and propagation geometry. This effect has not been included in previous...

A multifrequency (ten spectral lines between VHF and S band) coherent radio beacon is presently transmitting continuously from a 1000‐km, high‐inclination orbit for the purpose of characterizing transionospheric communication channel. Its high phase‐reference frequency (2891 MHz) permits direct observation complex‐signal scintillation, its very stable, sun‐synchronous allows repeated pre‐midnight observations at low latitudes near‐midnight auroral latitudes. We present here early results...

Abstract We present a new quantitative theory for the rate of change total electron content index (ROTI) by noting its straightforward relationship to phase structure function ionospheric turbulence. The provides dependence ROTI on sampling interval, satellite motion, propagation geometry, and spectral shape, strength, anisotropy, drift irregularities. also useful approximations full that elucidate principal dependencies. show, example, varies with effective scan velocity ( V eff ) power ν −...

Preliminary results are presented from a campaign of coordinated measurements between the Chatanika radar and TRIAD satellite to investigate production mechanisms responsible for localized high‐latitude scintillations. The measured latitudinal variations plasma density electric field while field‐aligned current distribution with latitude. This information was used calculate linear growth rate convective instability. We find that ionization enhancements, which common feature auroral F‐region,...

The multiple‐scatter theory of wave propagation in randomly irregular media is now well developed. Moreover, work fields such as coherent optics and radio astronomy has stimulated the development asymptotic formulas that can be used various scattering regimes. In this paper power law phase screen model to derive form intensity correlation function for strong ionospheric when Fresnel radius lies within continuum. allows fully anisotropy medium. Asymptotic valid under conditions very are It...

A high‐performance rocket carrying a four‐frequency, phase‐coherent beacon and full complement of in situ diagnostic instrumentation was launched into active equatorial spread F on July 17, 1979. In this paper we report the results spectrally analyzing phase‐scintillation Langmuir probe data. By using simultaneous backscatter data from Altair radar were able to establish that scintillation develops high‐density regions adjacent prominent plume structures associated depletions. these spectra...

During the PLUMEX I rocket flight from Kwajalein Island, plasma density and electric field fluctuations were measured in situ, simultaneous with ground‐based radar backscatter measurements at 0.96‐m 0.36‐m wavelengths. The penetrated an extremely turbulent topside region which had associated intense backscatter. As by power was decaying time during after flight. intermediate wavelength (0.1–10 km) situ electron are described a companion paper, while here we report transitional short results...

Using the east‐west drift of equatorial spread‐F (ESF) irregularities as tracers for horizontal bulk plasma motion, we show that a velocity shear (with altitude) in exists nighttime F‐layer. When combined with incoherent‐scatter measurements vertical motion F‐layer, find evidence two‐dimensional flow pattern F‐region around E‐region sunset resembles vortex. The vortex is attributed to (1) set up by dynamo begins function sunset, and (2) postsunset rise existence verifies importance eastward...

The first height‐resolved altitude profiles of the Joule heating rate obtained by using Chatanika, Alaska, incoherent scatter radar are presented. measured typically maximizes at an that is well above current density maximum. For a reasonable model neutral atmosphere, it also found maximum occurs corresponding Pedersen conductivity these data eastward auroral electrojet was centered near 130 km, while westward 10 km lower in during its most intense period. It inferred this large difference...

Description of an incoherent scatter radar experiment performed at the 23-cm facility in Chatanika, Alaska. The has provided a direct method for measuring ionospheric plasma transport velocity vector over long periods with relatively good time resolution. Since F-region this site is closely associated magnetospheric convection, particularly night, can provide important information about behavior magnetosphere.

The spectral characteristics of equatorial F region irregularities with scale sizes from a few kilometers to several hundred have been measured using data the Atmospheric Explorer‐E satellite. spectra admit expected power law characterization mean index near 2. There is, however, systematic decrease in increasing perturbation strength which has not previously reported. Nearly simultaneous phase scintillation Wideband satellite were also spectrally analyzed for comparison AE‐E data. same was...

Phase screen models have been used for nearly three decades to facilitate the application of scintillation theory data interpretation. Only recently, however, as large amounts multifrequency phase‐coherent beacon analyzed, has full potential model realized. This paper presents a review phase interpretation from Defense Nuclear Agency's Wideband satellite (international designation P76‐5), which was operational May 1976 until August 1979. The signal structure and experiment configuration...

A uniquely located, statistically prominant radiowave scintillation enhancement has been identified in nighttime auroral‐zone data. The occurs whenever the propagation path coincides with an L‐shell region of diffuse auroral particle precipitation. It is hypothesized that this a purely geometric effect due to sheet‐like ionospheric irregularity structures aligned along L‐shells. This hypothesis confirmed by spaced‐receiver data showing diffraction pattern elongated geomagnetic east‐west...

The results of simultaneous thermospheric neutral wind and ionization drift measurements from near College, Alaska ( L = 5.6, Λ 65°) are presented. data were obtained by observing the Doppler shift 6300 Å atomic oxygen line with 15‐cm Fabry‐Perot interferometer Michigan Airglow Observatory which is located temporarily at Ester Dome, Alaska. Ionization drifts measured Chatanika incoherent scatter radar facility. These indicate that in premidnight sector both generally westward. This westward...

Abstract We extend the power law phase screen theory for ionospheric scintillation to account case where refractive index irregularities follow a two‐component inverse spectrum. The model includes, as special cases, an unmodified and modified with spectral break that may assume role of outer scale, intermediate or inner scale. As such, it provides framework investigating effects on statistics. Using this model, we solve fourth moment equation governing intensity variations following...

Recent analyses of auroral‐zone spaced‐receiver measurements have shown that the regions where sheetlike irregularities occur are confined to equatorward portion nighttime scintillation zone westward and eastward electrojets flow. Poleward this region, rodlike. For satellites in highly eccentric orbits, technique can be used measure ionospheric drifts. Simultaneous incoherent‐scatter radar revealed two types F region ionization enhancements believed source persistent features on polar...

The most persistent, identifiable feature on intensity and phase scintillation records of coherent beacon signals recorded near Fairbanks, Alaska during several months in 1976 is a narrow region enhanced to the south station. On high‐elevation passes occurs magnetic zenith, suggesting that it could be geometric enhancement produced by field‐aligned irregularities. also occurs, however, medium low‐elevation when minimum off‐field angle tens degrees. observations, therefore, represent evidence...

Two rocket payloads carrying plasma density probes with high spatial resolution have been flown in the auroral zone during active conditions. Simultaneous Wideband satellite scintillation and Chatanika incoherent scatter radar observations were made order to study properties of high‐latitude irregularities their effects on radio wave transmission. Unlike barium cloud striations bottomside equatorial spread F , observed power law dependence does not seem be due steepening kilometer‐scale...

This paper reports the results of incoherent scatter radar observations high-altitude ion drifts and other plasma parameters made February 24, 1972, at Chatanika, Alaska (L = 5.7), during a period magnetic disturbance. For this experiment, conducted between 0909 to 1303 UT (2309 0303 AST), line sight was held fixed in meridian plane so that observed north-south could be interpreted terms westward electric field ranged magnitude from −10 +35 mV m−1. The confirm many effects found previously...

We present the Radio Occultation Scintillation Simulator (ROSS), which uses multiple phase screen method (MPS) to simulate forward scatter of radio waves by irregularities in equatorial ionosphere during occultation experiments. ROSS simulates propagation through plasma bubbles are modeled as homogeneous electron density fluctuations modulated a Chapman profile altitude and Gaussian window magnetic east‐west direction. adjust parameters model using profiles derived from ALTAIR incoherent...