Multi‐level model of radiation transport in inhomogeneous plasma

Marenkov, E. D.; Krasheninnikov, S. I.; Pshenov, A. A.

doi:10.1002/ctpp.201700132

Cited by 9 publications

(11 citation statements)

References 20 publications

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“…Radiation trapping increases the abundancies of the excited states of the hydrogen neutrals and therefore changes the ionization/recombination rates [6]. It can also cause a noticeable anisotropy of the radiation-associated power fluxes inside the hydrogen recycling region [7]. Finally, recent studies at TCV [8,9] and 1D simulations conducted in their support [10], indicate that the rollover of the plasma flux to the divertor targets, which is the main experimental manifestation of detachment, is closely connected to the increase of…”

Section: Introductionmentioning

confidence: 96%

On the role of hydrogen radiation absorption in divertor plasma detachment

et al. 2019

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Transition to the detached divertor regime that allows lowering the peak power loads on the divertor targets to a tolerable level requires low plasma temperature Te ~ 1 eV and high plasma density ne ~ 1021 m−3 in front of the target. Under such conditions, radiation trapping of the Lyman lines of hydrogen isotopes becomes important. It can influence both energy balance and the ionization/recombination rates significantly. Nevertheless, opacity is typically neglected in the 2D edge transport codes used to study the divertor plasma detachment. We report on the first in-depth investigation of radiation opacity effects on transition to detachment. Simulations are performed with the SOLPS 4.3 code package using a DIII-D size tokamak as a particular example. It is found that in pure hydrogen plasma suppression of the neutral hydrogen radiation loss due to the photon absorption makes reaching the detached plasma regime more difficult. A significantly higher average separatrix plasma pressure is required to reach a similar degree of detachment. Adding plasma impurities compensates for the reduced neutral radiation and offsets the effect of opacity. In a carbon device, where the impurity source is due to erosion of the divertor components and is strongly connected to the edge plasma density, the absorbed fraction of the hydrogen radiation is easily compensated with the increasing carbon radiation loss. However, nowadays, in the more relevant case of the full-metal wall and seeded impurity with the feedback-controlled content, the increase of the edge plasma density alone is insufficient to compensate for trapping of the hydrogen radiation. In this case, achievement of the desired degree of detachment requires higher average separatrix plasma pressure or seeded impurity content than those obtained from the transparent plasma model.

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Section: Introductionmentioning

confidence: 96%

On the role of hydrogen radiation absorption in divertor plasma detachment

et al. 2019

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“…Gas radiation properties are commonly used in various research elds, including atmospheric radiation transferring, atmospheric remote sensing, and ecological monitoring [1][2][3]. ey also exhibit outstanding advantages in space-based applications, such as spectral detection, thermal protection, and hypersonic target detection and tracking [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Multiscale-Band K-Distribution Model for Molecules in High-Temperature Gases

Shi

Zhang

et al. 2022

Journal of Spectroscopy

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Radiation heat transfer plays a dominant role in high-temperature flow field. Rapid and reliable calculation of spectral radiation properties is beneficial for thermal analysis and detection of radiation target. In this paper, a multiscale-band k-distribution model is proposed for the study of radiation properties in high-temperature gases. The accurate absorption coefficients are firstly calculated using the line-by-line model. The slope of the accurate absorption coefficient line and its slope threshold are then extracted and analyzed, which act as a basis to divide the absorption coefficient line into multiple segments. For different segments, different bandwidths are chosen for the corresponding band k-distribution model. In the model, the 7-point Gauss–Lobatto method is employed to obtain the optimized absorption coefficients. These optimized absorption coefficients formed the absorption coefficient database. The radiation intensities of gases are finally calculated and analyzed based on the optimized database. Experimental results suggest that the multiscale-band k-distribution model can improve the efficiency up to 35% compared with the widely used narrow-band k-distribution model. Simultaneously, the relative calculation error is less than 5% compared with the most accurate line-by-line model.

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“…In the magnetic fusion framework, the motiva-66 tion for this paper is the need of accuracy in transport codes. 67 At the edge of several tokamaks, the so-called divertor region 68 contains a cold plasma in recombining regime (typically T e < 69 5 eV and N e > 10 14 cm −3 ), which is affected by significant 70 radiation trapping at frequencies near the hydrogen Lyman 71 series; these opacity effects have been demonstrated both 72 experimentally and numerically [26][27][28][29][30][31]. In the framework 73 of ITER preparation, simulations of the Lyman line radiation 74 transport in the divertor have shown that the opacity provides 75 a significant additional source of excited atoms, which can 76 affect the plasma ionization-recombination balance.…”

Section: Introductionmentioning

confidence: 99%

“…81 The radiative transfer simulations reported in Refs. [29][30][31][32] 82 were performed within the complete redistribution approxi-83 mation, i.e., assuming that the frequency and the direction 84 of a photon outgoing from a scattering process are indepen-85 dent of those of the incoming photon. Although convenient 86 for calculations, the complete redistribution approxima-87 tion is not systematically valid in tokamak edge plasma 88 conditions.…”

Section: Introductionmentioning

confidence: 99%

Collisional redistribution of hydrogen line radiation in low- and moderate-density magnetized plasmas

Rosato

2021

Phys. Rev. E

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Multi‐level model of radiation transport in inhomogeneous plasma

Cited by 9 publications

References 20 publications

On the role of hydrogen radiation absorption in divertor plasma detachment

On the role of hydrogen radiation absorption in divertor plasma detachment

Multiscale-Band K-Distribution Model for Molecules in High-Temperature Gases

Collisional redistribution of hydrogen line radiation in low- and moderate-density magnetized plasmas

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