Reduced model of high-Z impurity redeposition and erosion in tokamak divertor and its application to DIII-D experiments

doi:10.1088/1361-6587/ab5144

Title: Reduced model of high-Z impurity redeposition and erosion in tokamak divertor and its application to DIII-D experiments

Abstract

A reduced model of high-Z impurities erosion and redeposition is presented to analyze net erosion of tungsten material in divertor attached plasma conditions measured in DIII-D experiments. This reduced model is tailored to quantify the redeposition and the net erosion on high-Z material samples of sufficiently small dimensions to be considered exposed to uniform plasma conditions. For those uniform plasma conditions, the spatial distribution of redeposited high-Z impurities is well approximated by an analytical distribution characterized by a few parameters. The fraction of high-Z impurity eroding and redepositing on a material sample is then obtained by integrating this distribution across the material sample. Here, the ratio of net erosion rates of tungsten measured experimentally from tungsten samples of different sizes exposed to the same attached plasma conditions are well reproduced with this reduced model. It is shown that uncertainties induced by radially non-uniform plasma conditions in experiments can be significantly reduced by exposing samples to high density divertor plasma. Several enhanced experimental setups are proposed to measure and compare net erosion rates from samples of various areas during a single plasma experiment.

Authors:

^[1];

^[2];

^[3]; Abrams, T. ^[4]; Wang, H. Q. ^[4]; McLean, A. G. ^[5];

^[4]

Oak Ridge Associated Univ., Oak Ridge, TN (United States)
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Univ. of California San Diego, La Jolla, CA (United States)
General Atomics, San Diego, CA (United States)
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Publication Date:: 2019-11-11

Research Org.:: General Atomics, San Diego, CA (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Fusion Energy Sciences (FES)

OSTI Identifier:: 1573806

Grant/Contract Number:: FC02-04ER54698

Resource Type:: Accepted Manuscript

Journal Name:: Plasma Physics and Controlled Fusion

Additional Journal Information:: Journal Volume: 61; Journal Issue: 12; Journal ID: ISSN 0741-3335

Publisher:: IOP Science

Country of Publication:: United States

Language:: English

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; tungsten; redeposition; divertor; erosion

Citation Formats


                    Guterl, J., Wampler, W. R., Rudakov, D., Abrams, T., Wang, H. Q., McLean, A. G., and Snyder, P. Reduced model of high-Z impurity redeposition and erosion in tokamak divertor and its application to DIII-D experiments.  United States: N. p., 2019. 
        Web.  doi:10.1088/1361-6587/ab5144.

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                    Guterl, J., Wampler, W. R., Rudakov, D., Abrams, T., Wang, H. Q., McLean, A. G., & Snyder, P. Reduced model of high-Z impurity redeposition and erosion in tokamak divertor and its application to DIII-D experiments.  United States.  doi:10.1088/1361-6587/ab5144.

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                    Guterl, J., Wampler, W. R., Rudakov, D., Abrams, T., Wang, H. Q., McLean, A. G., and Snyder, P. Mon .  
        "Reduced model of high-Z impurity redeposition and erosion in tokamak divertor and its application to DIII-D experiments".  United States.  doi:10.1088/1361-6587/ab5144.  https://www.osti.gov/servlets/purl/1573806.

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@article{osti_1573806,

  title        = {Reduced model of high-Z impurity redeposition and erosion in tokamak divertor and its application to DIII-D experiments},

  author       = {Guterl, J. and Wampler, W. R. and Rudakov, D. and Abrams, T. and Wang, H. Q. and McLean, A. G. and Snyder, P.},

  abstractNote = {A reduced model of high-Z impurities erosion and redeposition is presented to analyze net erosion of tungsten material in divertor attached plasma conditions measured in DIII-D experiments. This reduced model is tailored to quantify the redeposition and the net erosion on high-Z material samples of sufficiently small dimensions to be considered exposed to uniform plasma conditions. For those uniform plasma conditions, the spatial distribution of redeposited high-Z impurities is well approximated by an analytical distribution characterized by a few parameters. The fraction of high-Z impurity eroding and redepositing on a material sample is then obtained by integrating this distribution across the material sample. Here, the ratio of net erosion rates of tungsten measured experimentally from tungsten samples of different sizes exposed to the same attached plasma conditions are well reproduced with this reduced model. It is shown that uncertainties induced by radially non-uniform plasma conditions in experiments can be significantly reduced by exposing samples to high density divertor plasma. Several enhanced experimental setups are proposed to measure and compare net erosion rates from samples of various areas during a single plasma experiment.},

  doi          = {10.1088/1361-6587/ab5144},

  journal      = {Plasma Physics and Controlled Fusion},

  number       = 12,

  volume       = 61,

  place        = {United States},

  year         = {2019},

  month        = {11}

}

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Title: Reduced model of high-Z impurity redeposition and erosion in tokamak divertor and its application to DIII-D experiments

Abstract

Citation Formats

II. The energy spectrum of ejected atoms during the high energy sputtering of gold journal, August 1968

Tungsten as material for plasma-facing components in fusion devices journal, August 2011

High-Z material erosion and its control in DIII-D carbon divertor journal, August 2017

Material erosion at the vessel walls of future fusion devices journal, March 2003

Plasma-surface interaction in the Be/W environment: Conclusions drawn from the JET-ILW for ITER journal, August 2015

An experimental comparison of gross and net erosion of Mo in the DIII-D divertor journal, July 2013

Near‐surface sputtered particle transport for an oblique incidence magnetic field plasma journal, August 1990

Plasma–wall transition in an oblique magnetic field journal, January 1982

Dirac R -matrix calculations for the electron-impact excitation of neutral tungsten providing noninvasive diagnostics for magnetic confinement fusion journal, May 2018

Measurements of net erosion and redeposition of molybdenum in DIII-D journal, July 2013

Net versus gross erosion of high- Z materials in the divertor of DIII-D journal, April 2014

Modelling of tungsten re-deposition coefficient journal, August 2015

The inter-ELM tungsten erosion profile in DIII-D H-mode discharges and benchmarking with ERO+OEDGE modeling journal, April 2017

Tridyn-binary collision simulation of atomic collisions and dynamic composition changes in solids journal, November 1988

Gross and net erosion of tungsten in the outer strike-point region of ASDEX Upgrade journal, January 2016

Energy spectra of sputtered species under sub-keV ion bombardment: experiments and computer simulations journal, April 1999

Kinetic Theory Analysis of Sheaths and Shocks journal, January 1996

Experimental validation of a model for particle recycling and tungsten erosion during ELMs in the DIII-D divertor journal, December 2018

Erosion of tungsten and carbon markers in the outer divertor of ASDEX-Upgrade journal, March 2007

Tungsten divertor erosion in all metal devices: Lessons from the ITER like wall of JET journal, July 2013

A full tungsten divertor for ITER: Physics issues and design status journal, July 2013

Divertor materials evaluation system (DiMES) journal, October 1998

Simulation of the plasma-wall interaction in a tokamak with the Monte Carlo code ERO-TEXTOR journal, May 2000

Analysis of a tungsten sputtering experiment in DIII-D and code/data validation of high redeposition/reduced erosion journal, May 2015

Assessment of erosion, deposition and fuel retention in the JET-ILW divertor from ion beam analysis data journal, August 2017

Tungsten erosion in the outer divertor of JET journal, June 2007

Particle trajectories in a sheath in a strongly tilted magnetic field journal, March 1998

Overview of the recent DiMES and MiMES experiments in DIII-D journal, December 2009

Monte Carlo simulations of tungsten redeposition at the divertor target journal, January 2014

II. The energy spectrum of ejected atoms during the high energy sputtering of gold
journal, August 1968

Tungsten as material for plasma-facing components in fusion devices
journal, August 2011

High-Z material erosion and its control in DIII-D carbon divertor
journal, August 2017

Material erosion at the vessel walls of future fusion devices
journal, March 2003

Plasma-surface interaction in the Be/W environment: Conclusions drawn from the JET-ILW for ITER
journal, August 2015

An experimental comparison of gross and net erosion of Mo in the DIII-D divertor
journal, July 2013

Near‐surface sputtered particle transport for an oblique incidence magnetic field plasma
journal, August 1990

Plasma–wall transition in an oblique magnetic field
journal, January 1982

Dirac $R$ -matrix calculations for the electron-impact excitation of neutral tungsten providing noninvasive diagnostics for magnetic confinement fusion
journal, May 2018

Measurements of net erosion and redeposition of molybdenum in DIII-D
journal, July 2013

Net versus gross erosion of high- Z materials in the divertor of DIII-D
journal, April 2014

Modelling of tungsten re-deposition coefficient
journal, August 2015

The inter-ELM tungsten erosion profile in DIII-D H-mode discharges and benchmarking with ERO+OEDGE modeling
journal, April 2017

Tridyn-binary collision simulation of atomic collisions and dynamic composition changes in solids
journal, November 1988

Gross and net erosion of tungsten in the outer strike-point region of ASDEX Upgrade
journal, January 2016

Energy spectra of sputtered species under sub-keV ion bombardment: experiments and computer simulations
journal, April 1999

Kinetic Theory Analysis of Sheaths and Shocks
journal, January 1996

Experimental validation of a model for particle recycling and tungsten erosion during ELMs in the DIII-D divertor
journal, December 2018

Erosion of tungsten and carbon markers in the outer divertor of ASDEX-Upgrade
journal, March 2007

Tungsten divertor erosion in all metal devices: Lessons from the ITER like wall of JET
journal, July 2013

A full tungsten divertor for ITER: Physics issues and design status
journal, July 2013

Divertor materials evaluation system (DiMES)
journal, October 1998

Simulation of the plasma-wall interaction in a tokamak with the Monte Carlo code ERO-TEXTOR
journal, May 2000

Analysis of a tungsten sputtering experiment in DIII-D and code/data validation of high redeposition/reduced erosion
journal, May 2015

Assessment of erosion, deposition and fuel retention in the JET-ILW divertor from ion beam analysis data
journal, August 2017

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journal, June 2007

Particle trajectories in a sheath in a strongly tilted magnetic field
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Overview of the recent DiMES and MiMES experiments in DIII-D
journal, December 2009

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journal, January 2014