Regimes with Recombining Plasma in the ITER Divertor

Krasheninnikov, S. I.; Sigmar, D. J.; Soboleva, T. K.; Kukushkin, A. B.; Batischev, O. V.; Sigov, Yu. S.

doi:10.1002/ctpp.2150340253

Cited by 9 publications

(3 citation statements)

References 3 publications

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“…The general aspects of the physical model of detached divertor regimes described in Section 4.2 have been supported by a series of theoretical and experimental advances over the last several years. Although the theoretical basis and prediction of ionneutral effects leading to pressure loss existed long ago [90,91], experimental measurements of pressure loss on a number of experiments [92][93][94][95] engendered initial 'detachment' theories [48,49,96] that focused on explaining those results. Examples of experimental measurements of momentum (pressure) loss and accompanying particle flux reductions to the divertor plate are shown in Fig.…”

Section: Hydrogenic Processes and Divertor Detachmentmentioning

confidence: 99%

Chapter 4: Power and particle control

Divertor¹,

Database²,

Editors³

1999

Nucl. Fusion

282

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Abstract.Progress, since the ITER Physics Basis publication, in understanding the processes that will determine the properties of the plasma edge and its interaction with material elements in ITER is described. Experimental areas where significant progress has taken place are : energy transport in the SOL in particular of the anomalous transport scaling, particle transport in the SOL that plays a major role in the interaction of diverted plasmas with the main chamber material elements, ELM energy deposition on material elements and the transport mechanism for the ELM energy from the main plasma to the plasma facing components, the physics of plasma detachment and neutral dynamics including the edge density profile structure and the control of plasma particle content and He removal, the erosion of low and high Z materials in fusion devices, their transport to the core plasma and their migration at the plasma edge including the formation of mixed materials, the processes determining the size and location of the retention of tritium in fusion devices and methods to remove it and the processes determining the efficiency of the various fuelling methods as well as their development towards the ITER requirements. This experimental progress has been accompanied by the development of modelling tools for the physical processes at the edge plasma and plasma-materials interaction and the further validation of these models by comparing their predictions with the new experimental results. Progress in the modelling development and validation has been mostly concentrated in the following areas : refinement of the predictions for ITER with plasma edge modelling codes by inclusion of detailed geometrical features of the divertor and the introduction of physical effects, which can play a 2 major role in determining the divertor parameters at the divertor for ITER conditions such as hydrogen radiation transport and neutral-neutral collisions, modelling of the ion orbits at the plasma edge, which can play a role in determining power deposition at the divertor target, models for plasma-materials and plasma dynamics interaction during ELMs and disruptions, models for the transport of impurities at the plasma edge to describe the core contamination by impurities and the migration of eroded materials at the edge plasma and its associated tritium retention and models for the turbulent processes that determine the anomalous transport of energy and particles across the SOL. The implications for the expected performance of the reference regimes in ITER, the operation of the ITER device and the lifetime of the plasma facing materials are discussed. Introduction.This chapter outlines the significant progress achieved since the ITER Physics Basis in understanding basic scrape-off layer (SOL) and divertor processes in a tokamak. The interaction of plasma with first-wall surfaces will have considerable impact on the performance of fusion plasmas, the lifetime of plasma facing components, and the retention of tritium in next step Burning Plasma E...

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Section: Hydrogenic Processes and Divertor Detachmentmentioning

confidence: 99%

Chapter 4: Power and particle control

Divertor¹,

Database²,

Editors³

1999

Nucl. Fusion

282

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“…The possibility of establishing the 'gas blanket' regimes with high-density recombining hydrogen plasma in the ITER divertor was studied in [41] and [42], where numerical simulations of coupled plasma-radiation transport showed the crucial role of Lyman radiation opacity on the plasma parameters and peak heat flux to the divertor target. In particular, the Lyman lines opacity significantly increases the upstream plasma pressure, at which the divertor can operate in the 'gas blanket' regime.…”

Section: Transport Of Line Radiation In Opaque Plasmasmentioning

confidence: 99%

Physics of the edge plasma and first wall in fusion devices: synergistic effects

Krasheninnikov¹,

Pigarov²,

Lee³

2015

Plasma Phys. Control. Fusion

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Various synergistic effects resulting from plasma-wall interactions in magnetic fusion devices are considered. The crucial role of the first wall out-gassing processes in the recovery of pedestal density in the high-confinement mode of tokamak operation after giant type-I edge localized modes (ELMs) transient events as well as in the setting the ELM period is discussed. The shielding effects of vapor plasma formed during interactions of extremely large plasma heat fluxes with material surfaces are analyzed. The strongly non-linear impact of secondary electron emission from the divertor target on the incident plasma heat flux is discussed.

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“…All of these recent plasma recombination results point to an interesting possibility in solving the divertor heat load problem for ITER-like tokamaks. The idea is based on the interplay between plasma and neutral fluid dynamics (Krasheninnikov et al 1994). Because of plasma recombination and the ionization of the neutral gas in the divertor region, strong downstream plasma and upstream neutral gas flows are generated.…”

Section: Introductionmentioning

confidence: 99%

K–ε compressible 3D neutral fluid turbulence modelling of the effect of toroidal cavities on flame-front propagation in the gas-blanket regime for tokamak divertors

Vahala

Morrison

et al. 1997

J. Plasma Phys.

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Recent experiments and 2D laminar plasma–fluid simulations have indicated that plasma detachment from the divertor plate is strongly tied to plasma recombination. With plasma recombination, a neutral gas blanket will form between the divertor plate and the plasma frame front. Because of plasma-neutral coupling, the plasma flow along the field lines will drive neutral gas flow with Mach number [ges ]1 and Reynolds number [ges ]1000. A compressible set of conservation and transport equations are solved with 2D mean toroidal flow and 3D turbulence effects over various toroidal cavity geometries. The radial structure of the temperature profile is determined for both turbulent and laminar flow as the flame front propagates down the toroidal cavity. Quantitative results are obtained for the increased heat transfer to the toroidal walls due to turbulence as well as radial profiles for the transport coefficients. It is found that heat loads to the toroidal walls can be increased by factors of 5–20 over that for laminar flow for the cavity geometries studied here. This increased heat transfer to the toroidal walls will lead to decreased levels of heat flux impinging on the divertor plate.

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Regimes with Recombining Plasma in the ITER Divertor

Cited by 9 publications

References 3 publications

Chapter 4: Power and particle control

Chapter 4: Power and particle control

Physics of the edge plasma and first wall in fusion devices: synergistic effects

K–ε compressible 3D neutral fluid turbulence modelling of the effect of toroidal cavities on flame-front propagation in the gas-blanket regime for tokamak divertors

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