Proposed form for the atmospheric turbulence spatial spectrum at large scales

Greenwood, Darryl P.; Tarazano, Donald O.

doi:10.1364/josaa.25.001349

Cited by 15 publications

(4 citation statements)

References 17 publications

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“…α has been experimentaly estimated α ≈ 13 by simultaneous measurements of the spatial coherence outer scale L 0 between the GSM monitor, using the von Kármán spectra, and C 2 n balloon profiles using the Tatarski definition. 11 A factor has to be introduced in the von Kármán spectra so that the same outer scale L 0T may be considered as published by Reinhardt in 1972 12 and focused by Greenwood and Tarazano in 2008: 13 Φ θ (k) = 0.033C 2 θ k 2 + 1.071…”

Section: Spatial Resolution At Dome Cmentioning

confidence: 99%

Optical turbulence and outer scales above Dome C in Antarctica

Trinquet

Agabi²,

Vernin³

et al. 2008

SPIE Proceedings

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Dome C in Antarctica is a particular astronomical site when considering the optical turbulence conditions. From the first winterover campaign performed in 2005 at Dome C, the set of 34 meteorological balloon profiles has been analyzed. The meteorological balloons were equipped with microthermal sensors used to sense the vertical profile of the optical turbulence intensity C 2 n. The C 2 n median profile, mean temperature and mean horizontal wind speed are given. The C 2 n median profile is characterized by a very strong and thin turbulent surface layer. The surface layer height is defined. The median outer scale profile at Dome C is computed using the Tatarski definition. The von Kármán outer scale is also deduced. The integrated parameters as Fried parameter r 0 , coherence time τ 0 , isoplanatic angle θ 0 and the spatial-coherence outer scale L 0 used to define astronomical site quality, are computed at 8 m above the ground and above the turbulent surface layer.

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Section: Spatial Resolution At Dome Cmentioning

confidence: 99%

Optical turbulence and outer scales above Dome C in Antarctica

Trinquet

Agabi²,

Vernin³

et al. 2008

SPIE Proceedings

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“…The main feature of the VK model is a saturation of the power density in the range f L −1 0 at the level of L 11/3 0 . An alternative model without saturation but with a change in exponent of power law, was proposed by Greenwood and Tarazano (GT) (Greenwood & Tarazano 1974):…”

Section: Non-kolmogorov Models With Outer Scalementioning

confidence: 99%

Stellar scintillation on large and extremely large telescopes

Kornilov

2012

Monthly Notices of the Royal Astronomical Society

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The accuracy of ground-based astronomical photometry is limited by two factors: photon statistics and stellar scintillation arising when starlight passes through the Earth's atmosphere. This paper examines the theoretical role of the outer scale L O of the optical turbulence (OT), which suppresses the low-frequency component of the scintillation. It is shown that for typical values of L O ∼ 25-50 m, this effect becomes noticeable for telescopes of diameter about 4 m. On extremely large, 30-40 m, telescopes with exposures longer than a few seconds, the inclusion of the outer scale in the calculation reduces the scintillation power by more than a factor of 10 relative to conventional estimates. The details of this phenomenon are discussed for various models of non-Kolmogorov turbulence. In addition, a quantitative description of the influence of the telescope central obscuration on the measured scintillation noise is introduced and combined with the effect of the outer scale. Evaluation of the scintillation noise on future TMT and E-ELT telescopes predicts an amplitude of approximately 10 μmag for a 60-s exposure.

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“…Before describing those constraints, let us first define the 3D PSD of the index of refraction fluctuations for a turbulence volume described by a power law with an inner and outer scale [31][32][33] E Q -T A R G E T ; t e m p : i n t r a l i n k -; e 0 0 1 ; 1 1 6 ; 6 2 8…”

Section: Introductionmentioning

confidence: 99%

“…Before describing those constraints, let us first define the 3D PSD of the index of refraction fluctuations for a turbulence volume described by a power law with an inner and outer scale 31 – 33 Φn(κ,α,z)=A(α)C˜n2(z)exp(−κ2/κm2)(κ2+κ02)(−α/2).In Eq. (1), A(α)=(1/4π2)cos(πα/2)Γ[α−1].…”

Section: Introductionmentioning

confidence: 99%

Wave optics simulations of plane-wave propagation in non-Kolmogorov turbulence

2022

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We explore the practical limits for wave optics simulations of plane-wave propagation in non-Kolmogorov turbulence using the split-step method and thin phase screens. These limits inform two simulation campaigns where the relationship between volume turbulence strength and normalized intensity variance for various non-Kolmogorov power laws is explored. We find that simulation of power-law exponents near 3 are limited to turbulence strengths with Rytov numbers of 7 when the simulation side-length sampling rate is limited to 8192. Under these same conditions, it is possible to simulate volume turbulence strength out to Rytov numbers of 12 for Kolmogorov turbulence out to a power-law exponent of 4. We also demonstrate that the peak scintillation and Rytov number where peak scintillation occurs increases approximately linearly with the power-law exponent. Also, if turbulence strength is fixed, the relationship between the scintillation index and power law depends on the operating regime. In weak turbulence, the relationship is negative, and it is positive in strong turbulence. This work also emphasizes the importance of properly scaling turbulence strength when comparing results between different mediums with different power laws and the influence and importance of defining inner and outer scales in these simulations.

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Proposed form for the atmospheric turbulence spatial spectrum at large scales

Cited by 15 publications

References 17 publications

Optical turbulence and outer scales above Dome C in Antarctica

Optical turbulence and outer scales above Dome C in Antarctica

Stellar scintillation on large and extremely large telescopes

Wave optics simulations of plane-wave propagation in non-Kolmogorov turbulence

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