A linearized theory of transient laser heating in fluids

Holmes, Richard B.; Myers, Robert; Duzy, C.

doi:10.1103/physreva.44.6862

Cited by 6 publications

(4 citation statements)

References 24 publications

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“…Again, based on previously published theoretical explorations, [6][7][8][9][10] we hypothesized that the simulated turbulence and SSTB would increase the amount of scintillation found in a backpropagated point-source beacon due to TTBI. As a result, the log-amplitude variance σ 2 χ and branchpoint density D BP for the TTBI case would typically increase in comparison to the simulated diffraction-limited, turbulence-only, and SSTB-only cases.…”

Section: Backpropagated Point-source Beaconmentioning

confidence: 99%

“…[1][2][3][4][5] There is, nevertheless, an interaction that occurs between turbulence and thermal blooming at wavelengths near 1 μm. [6][7][8][9][10] This so-called turbulence thermal blooming interaction (TTBI), in practice, results in an increased amount of scintillation, which is the constructive and destructive interference that results from propagating high-power laser beams through distributed-volume atmospheric aberrations or "deep turbulence." In general, the scintillation caused by turbulence results in localized hot spots that cause localized heating of the atmosphere.…”

Section: Introductionmentioning

confidence: 99%

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Wave-optics investigation of turbulence thermal blooming interaction: I. Using steady-state simulations

Spencer

2020

Opt. Eng.

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Part I of this two-part paper uses wave-optics simulations to look at the Monte Carlo averages associated with turbulence and steady-state thermal blooming (SSTB). The goal is to investigate turbulence thermal blooming interaction (TTBI). At wavelengths near 1 μm, TTBI increases the amount of constructive and destructive interference (i.e., scintillation) that results from high-power laser beam propagation through distributed-volume atmospheric aberrations. As a result, we use the spherical-wave Rytov number and the distortion number to gauge the strength of the simulated turbulence and SSTB. These parameters simplify greatly given propagation paths with constant atmospheric conditions. In addition, we use the log-amplitude variance and the branch-point density to quantify the effects of TTBI. These metrics result from a point-source beacon being backpropagated from the target plane to the source plane through the simulated turbulence and SSTB. Overall, the results show that the log-amplitude variance and branch-point density increase significantly due to TTBI. This outcome poses a major problem for beam-control systems that perform phase compensation. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Section: Backpropagated Point-source Beaconmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Wave-optics investigation of turbulence thermal blooming interaction: I. Using steady-state simulations

Spencer

2020

Opt. Eng.

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“…Again, based on previously published theoretical explorations, [6][7][8][9][10] we hypothesized that the simulated turbulence and TDTB would increase the amount of scintillation found in a backpropagated point-source beacon due to TTBI. As a result, the log-amplitude variance σ 2 χ and branch-point density D BP for the TTBI case would typically increase in comparison to the simulated diffraction-limited, turbulence-only, and TDTB-only cases.…”

Section: Backpropagated Point-source Beaconmentioning

confidence: 99%

Wave-optics investigation of turbulence thermal blooming interaction: II. Using time-dependent simulations

Spencer

2020

Opt. Eng.

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Part II of this two-part paper uses wave-optics simulations to look at the Monte Carlo averages associated with turbulence and time-dependent thermal blooming (TDTB). The goal is to investigate turbulence thermal blooming interaction (TTBI). At wavelengths near 1 μm, TTBI increases the amount of constructive and destructive interference (i.e., scintillation) that results from high-power laser beam propagation through distributed-volume atmospheric aberrations. As a result, we use the spherical-wave Rytov number, the number of wind-clearing periods, and the distortion number to gauge the strength of the simulated turbulence and TDTB. These parameters simply greatly given propagation paths with constant atmospheric conditions. In addition, we use the log-amplitude variance and the branch-point density to quantify the effects of TTBI. These metrics result from a point-source beacon being backpropagated from the target plane to the source plane through the simulated turbulence and TDTB. Overall, the results show that the log-amplitude variance and branch-point density increase significantly due to TTBI. This outcome poses a major problem for beam-control systems that perform phase compensation. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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“…In the presence of a quasi-monochromatic electromagnetic field with frequency ω, electric field 1∕2Êe −iωt c:c:, and time-average intensity (Poynting flux) I Re ε∕μ p cÊ ·Ê ∕8π, the fluid equations describing the processes of interest are expressible in the form [1,2,[30][31][32][33] …”

Section: A Temperature Equationmentioning

confidence: 99%

Determination of absorption coefficient based on laser beam thermal blooming in gas-filled tube

et al. 2014

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Thermal blooming of a laser beam propagating in a gas-filled tube is investigated both analytically and experimentally. A self-consistent formulation taking into account heating of the gas and the resultant laser beam spreading (including diffraction) is presented. The heat equation is used to determine the temperature variation while the paraxial wave equation is solved in the eikonal approximation to determine the temporal and spatial variation of the Gaussian laser spot radius, Gouy phase (longitudinal phase delay), and wavefront curvature. The analysis is benchmarked against a thermal blooming experiment in the literature using a CO₂ laser beam propagating in a tube filled with air and propane. New experimental results are presented in which a CW fiber laser (1 μm) propagates in a tube filled with nitrogen and water vapor. By matching laboratory and theoretical results, the absorption coefficient of water vapor is found to agree with calculations using MODTRAN (the MODerate-resolution atmospheric TRANsmission molecular absorption database) and HITRAN (the HIgh-resolution atmospheric TRANsmission molecular absorption database).

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A linearized theory of transient laser heating in fluids

Cited by 6 publications

References 24 publications

Wave-optics investigation of turbulence thermal blooming interaction: I. Using steady-state simulations

Wave-optics investigation of turbulence thermal blooming interaction: I. Using steady-state simulations

Wave-optics investigation of turbulence thermal blooming interaction: II. Using time-dependent simulations

Determination of absorption coefficient based on laser beam thermal blooming in gas-filled tube

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