In situ measurements of the spectral characteristics of<i>F</i>region ionospheric irregularities

Dyson, P. L.; McClure, J. P.; Hanson, W. B.

doi:10.1029/ja079i010p01497

Cited by 282 publications

(110 citation statements)

References 20 publications

(13 reference statements)

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“…Costa and Kelley (1978) analyzed the bottom side electron density data, obtained from the same¯ight, and found that the steepened coherent structures exhibited shallow spectra, with k )2 power law behavior in intermediate (10 km > k > 100 m) and transitional (100 m > k > 10 m) scales instead of a turbulent cascade of structures. Similar k )2 power law scaling was observed by Dyson et al (1974) using AE satellite data, by Morse et al (1977) in the Equion experiment and also by Kelley and Mozer (1972) using the electric ®eld data. Costa and Kelley (1978) found that sharp density gradients (gradient scale length, L < 100 m) could de-stabilize collisional drift waves.…”

Section: Introduction and Literature Reviewsupporting

confidence: 83%

Some new features of electron density irregularities over SHAR during strong spread F

Raizada

Sinha

2000

Annales Geophysicae

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Abstract. An RH-560 rocket¯ight was conducted from Sriharikota rocket range (SHAR) (14°N, 80°E, dip latitude 5.5°N) to study electron density and electric ®eld irregularities during spread F. The rocket was launched at 2130 local time (LT) and it attained an apogee of 348 km. Results of electron density¯uctuations are presented here. Two extremely sharp layers of very high electron density were observed at 105 and 130 km. The electron density increase in these layers was by a factor of 50 in a vertical extent of 10 km. Large depletions in electron density were observed around 175 and 238 km. Both sharp layers as well as depletions were observed also during the descent. The presence of sharp layers and depletions during the ascent and the descent of the rocket as well as an order of magnitude less electron density, in 150±300 km region during the descent, indicate the presence of strong large-scale horizontal gradients in the electron density. Some of the valley region irregularities (165±178 km), in the intermediate scale size range, observed during this¯ight, show spectral peaks at 2 km and can be interpreted in terms of the image striation theory suggested by Vickrey et al. The irregularities at 176 km do not exhibit any peak at kilometer scales and appear to be of new type. The growth rate of intermediate scale size irregularities, produced through generalized Rayleigh Taylor instability, was calculated for the 200± 330 km altitude, using observed values of electron density gradients and an assumed vertically downward wind of 20 ms )1 . These growth rate calculations suggest that the observed irregularities could be produced by the gradient drift instability.

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Section: Introduction and Literature Reviewsupporting

confidence: 83%

Some new features of electron density irregularities over SHAR during strong spread F

Raizada

Sinha

2000

Annales Geophysicae

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“…The k-'• one-dimensional in situ irregularity spectral density function (SDF) that previously had been associated with equatorial spread F from satellite data [Dyson et al, 1974] and with bottomside spread F using rocket data [Kelley et al, 1976;Morse et al, 1977] supports the notion that steep-gradients develop in the spread F process. Similar structures develop in low-altitude barium cloud instabilities .…”

mentioning

confidence: 64%

Simultaneous rocket‐borne beacon and in situ measurements of equatorial spread F—Intermediate wavelength results

Rino¹,

Tsunoda²,

Petričeks³

et al. 1981

J. Geophys. Res.

116

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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 of spectrally analyzing the beacon phase-scintillation and Langmuir probe data. By using simultaneous backscatter data from the Altair radar we were able to establish that the scintillation develops in high-density regions adjacent to the prominent plume structures and associated depletions. In these high-density regions the in situ spectra show a pronounced change in the power law slope near a spatial wavelength of 500 m. Larger scale structures admit a systematically varying power law index that is generally less than 2, in good agreement with a large body of Wideband satellite data and recently analyzed Atmospheric Explorer E data. Smaller-scale structures admit a spectral index much larger than 2. A single, overall power law near k -2 was found only in low-density regions that did not contribute significantly to the scintillation. The results presented here and in a companion paper suggest that refinements in the current theories of equatorial spread F near and above the F region peak are needed.

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“…In the horizontal domain, we interpret the The results in Figure 10 can also be compared ith the measurements made on OGO-6 (Dyson et al, 1974) and on AE-E . The 1.40-6 results showed a power spectral index near 2 for the 70 i to 7 km domain and the AE-E observations showed a spectral index near 2 in the km-to-hundreds of kilometer region.…”

Section: Horizontal Wave Number Spectramentioning

confidence: 80%

Composite equatorial spread F wave number spectra from medium to short wavelengths

Singh¹,

Szuszczewicz²

1984

J. Geophys. Res.

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In an effort to provide a full‐spectral classification of equatorial spread F irregularities from large‐scale behavior (≈100 km) to the meter‐size domain, we have analyzed a combination of rocket and satellite data that in concert cover the complete six decade irregularity distribution. Our results provide a composite perspective in the hierarchy of processes that contribute to the total phenomenon called equatorial spread F and provide “in situ” meter‐size irregularity measurements that help explain the relationship of spectral power at short wavelengths to that in the transitional and intermediate domain. In a synoptic perspective we find that medium and intermediate domains (≈ 50 km → 200 m) display k−1.5±0.4 and k−2.4±0.2 behavior, respectively, in both vertical and horizontal distributions. The transitional wavelengths (≈200 m → 20 m) are dominated by a steep one‐dimensional k−4.8±0.2 universal drift wave spectral behavior but break at kri ≳ 1 (λ ≲ 20 m) to much higher power levels, a result that is consistent with ground‐based radar results in the meter‐scale domain. Our shortest wavelength rocket results (1 m ≲ λ ≲ 20 m) are qualitatively consistent with a lower hybrid drift wave interpretation, but the presence of resonant structure in the observed spectral distribution strongly suggests a resonant wave‐particle interaction process. While our analyses point to specific spectral indices in each of the wavelength domains, we caution against the unique identification of any spectral index with a specific geoplasma mechanism. Clearly, time in the instability growth and decay process can modify the spectral index, as can changing ionospheric conditions, transport, and diffusion. Our satellite results provide for a large statistical sampling of spectral behavior in the various wavelength domains, point to the most probable spectral indices, and highlight their variability.

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In situ measurements of the spectral characteristics ofFregion ionospheric irregularities

Cited by 282 publications

References 20 publications

Some new features of electron density irregularities over SHAR during strong spread F

Some new features of electron density irregularities over SHAR during strong spread F

Simultaneous rocket‐borne beacon and in situ measurements of equatorial spread F—Intermediate wavelength results

Composite equatorial spread F wave number spectra from medium to short wavelengths

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