Molybdenum sources and transport in the Alcator C-Mod tokamak

Pappas, Dimitri; Lipschultz, B.; LaBombard, B.; May, M. J.; Pitcher, C.S.

doi:10.1016/s0022-3115(98)00597-2

Cited by 27 publications

(26 citation statements)

References 22 publications

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“…Most of the melting of high-Z PFCs observed in present devices is due to : poor thermal contact between high-Z coatings and the substrate, tile misalignments, and/or runaway electrons [374]. Energy densities during ITER transients may cause significant melting of the high Z PFCs [166,375] (from boronisation) and Mo self-sputtering are taken into account [377], while in RF heated discharges localised Mo sputtering near RF antennae was linked to high ion impact energies due to sheath rectification [290]. In ASDEX Upgrade (see Fig.…”

Section: Behaviour Of High-z Plasma-facing Components In Tokamak Expementioning

confidence: 99%

Chapter 4: Power and particle control

Loarte¹,

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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Section: Behaviour Of High-z Plasma-facing Components In Tokamak Expementioning

confidence: 99%

Chapter 4: Power and particle control

Loarte¹,

et al. 2007

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“…The inner and outer divertor surfaces are monitored with optics at the bottom of the vessel viewing poloidally through the divertor region. The geometry of the views of different first-wall surfaces are further detailed in reference [12]. The inverse photon efficiency for the Mo-I line, also known as S/XB, is utilized to convert the Mo-I photon brightness to influx (per unit area) based on a standard formalism [5,26].…”

Section: Introductionmentioning

confidence: 99%

A study of molybdenum influxes and transport in Alcator C-Mod

et al. 2001

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“…Studies of high-Z sources have been performed on limiter [2][3][4][5] and divertor tokamaks [6][7][8][9]. The issue of impurity penetration to the core has often been separately addressed through examination of recycling [10][11][12][13] and nonrecycling elements [11,12,[14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Molybdenum sources and transport in Alcator C-Mod

Lipschultz

Pappas

LaBombard

et al. 2001

Journal of Nuclear Materials

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We present a characterization of molybdenum sources, Γ Mo , core Mo density, n Mo , and their dependencies on Alcator C-Mod operational regimes. This includes sources from the divertor, the inner wall and the ICRF antenna limiters. We also present information characterizing the penetration of these impurities into the core plasma under different conditions based on penetration factors, PF=n Mo /Γ Mo (seconds). In general the inner wall Mo source is large (~10 18 /sec) but is found to be relatively uncorrelated with the core Mo level in diverted plasmas.The outer divertor source is of similar order to that from the inner wall and has a penetration factor in the range 10 -5 -2x10 -3 seconds depending on density and confinement mode. The antenna limiter Mo sources are typically smaller, but with higher penetration factors -10 -3 -2x10 -2 seconds. The behavior of the antenna limiter sources is consistent with physical sputtering due to the influence of RF sheath rectification.

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Molybdenum sources and transport in the Alcator C-Mod tokamak

Cited by 27 publications

References 22 publications

Chapter 4: Power and particle control

Chapter 4: Power and particle control

A study of molybdenum influxes and transport in Alcator C-Mod

Molybdenum sources and transport in Alcator C-Mod

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