Radiation Hydrodynamics

Castor, J.

doi:10.1017/cbo9780511536182

Cited by 258 publications

(265 citation statements)

References 150 publications

(258 reference statements)

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“…We also note that by neglecting the spatial derivatives of intensity in Eq. (1) we obtain the Sobolev approximation (Castor 2004).…”

Section: Cmf Calculation Of the Radiative Forcementioning

confidence: 99%

Comoving frame models of hot star winds

Krtička¹,

Kubát

2010

A&A

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We provide hot star wind models with radiative force calculated using the solution of comoving frame (CMF) radiative transfer equation. The wind models are calculated for the first stars, O stars, and the central stars of planetary nebulae. We show that without line overlaps and with solely thermal line broadening the pure Sobolev approximation provides a reliable estimate of the radiative force even close to the wind sonic point. Consequently, models with the Sobolev line force provide good approximations to solutions obtained with non-Sobolev transfer. Taking line overlaps into account, the radiative force becomes slightly lower, leading to a decrease in the wind mass-loss rate by roughly 40%. Below the sonic point, the CMF line force is significantly lower than the Sobolev one. In the case of pure thermal broadening, this does not influence the mass-loss rate, as the wind mass-loss rate is set in the supersonic part of the wind. However, when additional line broadening is present (e.g., the turbulent one) the region of low CMF line force may extend outwards to the regions where the mass-loss rate is set. This results in a decrease in the wind mass-loss rate. This effect can at least partly explain the low wind mass-loss rates derived from some observational analyses of luminous O stars.

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“…We also note that by neglecting the spatial derivatives of intensity in Eq. (1) we obtain the Sobolev approximation (Castor 2004).…”

Section: Cmf Calculation Of the Radiative Forcementioning

confidence: 99%

Comoving frame models of hot star winds

Krtička¹,

Kubát

2010

A&A

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“…Therefore, to include PR in detailed modeling of devices, the photon transport equation should be included in the set of carrier transport equations. [8][9][10] For photons with energy less than the band gap energy hm < E g À Á , absorption, emission, and scattering are weak and the wave equation describes very thoroughly the overall photon propagation. Mathematically, the equations of propagation are hyperbolic partial differential equations, and their numerical solution is relatively easy and stable.…”

Section: Introductionmentioning

confidence: 99%

Numerical Estimations of Carrier Generation–Recombination Processes and the Photon Recycling Effect in HgCdTe Heterostructure Photodiodes

Jóźwikowski

Kopytko

Rogalski

2012

Journal of Elec Materi

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An enhanced computer program has been applied to explain in detail the photon recycling effect which drastically limits the influence of radiative recombination on the performance of p-on-n HgCdTe heterostructure photodiodes. The computer program is based on a solution of the carrier transport equations, as well as the photon transport equations for semiconductor heterostructures. We distinguish photons in two energy ranges according to p + and n region with unequal band gaps. As a result, both the distribution of thermal carrier generation and recombination rates and spatial photon density distribution in photodiode structures have been obtained. The general conclusion, similar to our earlier work concerning 3-lm n-on-p HgCdTe heterostructure photodiodes, confirms the previous assertion by Humphreys that radiative recombination does not limit HgCdTe photodiode performance.

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“…We neglect his last three terms because we ignore spatial and temporal changes of n, the refractive index. 3 In Eq. (2), the fundamental variable, the intensity I (erg/cm 3 sec Hz sr), depends on time, position x, propagation direction Ω, and frequency ν.…”

Section: Derivation Of Equationsmentioning

confidence: 99%

Derivation and solution of multifrequency radiation diffusion equations for homogeneous refractive lossy media

Shestakov

Vignes

Stölken

2011

Journal of Computational Physics

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Starting from the radiation transport equation for homogeneous, refractive lossy media, we derive the corresponding time-dependent multifrequency diffusion equations. Zeroth and first moments of the transport equation couple the energy density, flux and pressure tensor. The system is closed by neglecting the temporal derivative of the flux and replacing the pressure tensor by its diagonal analogue. The system is coupled to a diffusion equation for the matter temperature. We are interested in modeling annealing of silica (SiO2). We derive boundary conditions at a planar air-silica interface taking account of reflectivities. The spectral dimension is discretized into a finite number of intervals leading to a system of multigroup diffusion equations. Three simulations are presented. One models cooling of a silica slab, initially at 2500 • K, for 10 s. The other two are 1D and 2D simulations of irradiating silica with a CO2 laser, λ = 10.59 µm. In 2D, we anneal a disk (radius = 0.4, thickness = 0.4 cm) with a laser, Gaussian profile (r0 = 0.5 mm for 1/e decay.)

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Radiation Hydrodynamics

Cited by 258 publications

References 150 publications

Comoving frame models of hot star winds

Comoving frame models of hot star winds

Numerical Estimations of Carrier Generation–Recombination Processes and the Photon Recycling Effect in HgCdTe Heterostructure Photodiodes

Derivation and solution of multifrequency radiation diffusion equations for homogeneous refractive lossy media

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