Spectroscopic measurements of impurity temperatures and parallel ion flows in the DIII-D divertor

Isler, R.C.; Brooks, N.H.; West, W.P.; Leonard, A. W.; McKee, G. R.; Porter, G. D.

doi:10.1016/s0022-3115(98)00824-1

“…Impurities migrate for longer distances if they leave the divertor region either as neutral atoms or ions pulled out of the divertor by the thermal force. Impurity ion flow velocities in the range of 20 km s −1 (out of the divertor) have been observed [120,281], with the magnitude agreeing with UEDGE calculations [282]. These impurities are eventually deposited at some distance from the strike point.…”

Section: Materials Migrationsupporting

confidence: 69%

Chapter 4: Power and particle control

Loarte¹,

Lipschultz

²

,

Kukushkin

³

et al. 2007

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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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“…Impurities migrate for longer distances if they leave the divertor region either as neutral atoms or ions pulled out of the divertor by the thermal force. Impurity ion flow velocities in the range of 20 km/s (out of the divertor) have been observed [120,280], with the magnitude agreeing with UEDGE calculations [281]. These impurities are eventually deposited at some distance from the strike point.…”

Section: Materials Migrationsupporting

confidence: 69%

“…Spectroscopic measurements of parallel flow velocities of low charge state impurity ions (CII, CIII, BII, HeII) is another alternative flow measurement [119,120]. Such measurements are roughly consistent with expectations for flow patterns in the divertor but direct comparisons with probes have not been made.…”

Section: Sol Flow and Classical Drifts Effectsmentioning

confidence: 81%

Chapter 4: Power and particle control

Divertor¹,

Database²,

Editors³

1999

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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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“…In spectroscopic observations of the edge plasma in TORE SUPRA [41], and in a series of measurements of low-Z ion and atomic spectra from the DIII-D divertor chamber [42]- [44], a full analysis of the Zeeman effect was again essential in order to extract ion temperatures. Other divertor studies employing spectroscopic measurements on Zeeman-split line profiles have been carried out on ASDEX-Upgrade [45] and JT-60U [46].…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic Studies of Cold Atomic Hydrogen and Deuterium Produced in a Tokamak Edge Plasma

Hey¹,

Chu²,

Hintz

³

2000

Contrib. Plasma Phys.

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Spectroscopic measurements of low‐n Balmer line profiles of atomic hydrogen and deuterium, emitted within the edge region of the TEXTOR‐94 tokamak plasma, have revealed the existence of a class of cold excited atoms, whose probable origin has been ascribed to electron impact‐induced molecular dissociation. Associated with these cold radiators are a second group of ‘lukewarm’ atoms, i.e. atoms heated by elastic collisions with hot protons (deuterons) diffusing outward from the plasma interior, as well as a third group of ‘hot’ atoms, produced in the corresponding excited states directly by charge‐exchange recombination between protons (deuterons) and boundary region atoms. A mechanism recently proposed to explain the heating process quantitatively, in terms of elastic atom‐ion collisions, is applied and discussed in this paper.

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Spectroscopic measurements of impurity temperatures and parallel ion flows in the DIII-D divertor

Cited by 14 publications

References 9 publications

Chapter 4: Power and particle control

Chapter 4: Power and particle control

Chapter 4: Power and particle control

Spectroscopic Studies of Cold Atomic Hydrogen and Deuterium Produced in a Tokamak Edge Plasma

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