Advances in understanding of high- Z material erosion and re-deposition in low- Z wall environment in DIII-D

doi:10.1088/1741-4326/aa6451

Title: Advances in understanding of high- Z material erosion and re-deposition in low- Z wall environment in DIII-D

Abstract

Dedicated DIII-D experiments coupled with modeling reveal that the net erosion rate of high-Z materials, i.e. Mo and W, is strongly affected by carbon concentration in the plasma and the magnetic pre-sheath properties. We have investigated different methods such as electrical biasing and local gas injection to control high-Z material erosion. The net erosion rate of high-Z materials is significantly reduced due to the high local re-deposition ratio. The ERO modeling shows that the local re-deposition ratio is mainly controlled by the electric field and plasma density within the magnetic pre-sheath. The net erosion can be significantly suppressed by reducing the sheath potential drop. A high carbon impurity concentration in the background plasma is also found to reduce the net erosion rate of high-Z materials. Both DIII-D experiments and modeling show that local ¹³CH ₄ injection can create a carbon coating on the metal surface. The profile of ¹³C deposition provides quantitative information on radial transport due to E × B drift and the cross-field diffusion. The deuterium gas injection upstream of the W sample can reduce W net erosion rate by plasma perturbation. The inter-ELM W erosion we measured in H-mode plasmas, rates at different radial locations are wellmore »« less

Publication Date:: 2017-03-24

Research Org.:: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); General Atomics, San Diego, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:: USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)

OSTI Identifier:: 1491638

Alternate Identifier(s):: OSTI ID: 1357016; OSTI ID: 1374606; OSTI ID: 1374610; OSTI ID: 1503985

Report Number(s):: SAND-2017-0016J; LLNL-JRNL-736452
Journal ID: ISSN 0029-5515; 650168

Grant/Contract Number:: AC04-94AL85000; GA-DE-SC0008698; AC05-06OR23100; FG02-07ER54917; AC05-00OR22725; FC02-04ER54698; AC52-07NA27344

Resource Type:: Accepted Manuscript

Journal Name:: Nuclear Fusion

Additional Journal Information:: Journal Volume: 57; Journal Issue: 5; Journal ID: ISSN 0029-5515

Publisher:: IOP Science

Country of Publication:: United States

Language:: English

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; erosion; deposition; high-Z materials; impurity

Citation Formats


                    Ding, R., Rudakov, D. L., Stangeby, P. C., Wampler, W. R., Abrams, T., Brezinsek, S., Briesemeister, A., Bykov, I., Chan, V. S., Chrobak, C. P., Elder, J. D., Guo, H. Y., Guterl, J., Kirschner, A., Lasnier, C. J., Leonard, A. W., Makowski, M. A., McLean, A. G., Snyder, P. B., Thomas, D. M., Tskhakaya, D., Unterberg, E. A., Wang, H. Q., and Watkins, J. G. Advances in understanding of high- Z material erosion and re-deposition in low- Z wall environment in DIII-D.  United States: N. p., 2017. 
        Web.  doi:10.1088/1741-4326/aa6451.

Copy to clipboard


                    Ding, R., Rudakov, D. L., Stangeby, P. C., Wampler, W. R., Abrams, T., Brezinsek, S., Briesemeister, A., Bykov, I., Chan, V. S., Chrobak, C. P., Elder, J. D., Guo, H. Y., Guterl, J., Kirschner, A., Lasnier, C. J., Leonard, A. W., Makowski, M. A., McLean, A. G., Snyder, P. B., Thomas, D. M., Tskhakaya, D., Unterberg, E. A., Wang, H. Q., & Watkins, J. G. Advances in understanding of high- Z material erosion and re-deposition in low- Z wall environment in DIII-D.  United States.  doi:10.1088/1741-4326/aa6451.

Copy to clipboard


                    Ding, R., Rudakov, D. L., Stangeby, P. C., Wampler, W. R., Abrams, T., Brezinsek, S., Briesemeister, A., Bykov, I., Chan, V. S., Chrobak, C. P., Elder, J. D., Guo, H. Y., Guterl, J., Kirschner, A., Lasnier, C. J., Leonard, A. W., Makowski, M. A., McLean, A. G., Snyder, P. B., Thomas, D. M., Tskhakaya, D., Unterberg, E. A., Wang, H. Q., and Watkins, J. G. Fri .  
        "Advances in understanding of high- Z material erosion and re-deposition in low- Z wall environment in DIII-D".  United States.  doi:10.1088/1741-4326/aa6451.  https://www.osti.gov/servlets/purl/1491638.

Copy to clipboard


                    
@article{osti_1491638,

  title        = {Advances in understanding of high- Z material erosion and re-deposition in low- Z wall environment in DIII-D},

  author       = {Ding, R. and Rudakov, D. L. and Stangeby, P. C. and Wampler, W. R. and Abrams, T. and Brezinsek, S. and Briesemeister, A. and Bykov, I. and Chan, V. S. and Chrobak, C. P. and Elder, J. D. and Guo, H. Y. and Guterl, J. and Kirschner, A. and Lasnier, C. J. and Leonard, A. W. and Makowski, M. A. and McLean, A. G. and Snyder, P. B. and Thomas, D. M. and Tskhakaya, D. and Unterberg, E. A. and Wang, H. Q. and Watkins, J. G.},

  abstractNote = {Dedicated DIII-D experiments coupled with modeling reveal that the net erosion rate of high-Z materials, i.e. Mo and W, is strongly affected by carbon concentration in the plasma and the magnetic pre-sheath properties. We have investigated different methods such as electrical biasing and local gas injection to control high-Z material erosion. The net erosion rate of high-Z materials is significantly reduced due to the high local re-deposition ratio. The ERO modeling shows that the local re-deposition ratio is mainly controlled by the electric field and plasma density within the magnetic pre-sheath. The net erosion can be significantly suppressed by reducing the sheath potential drop. A high carbon impurity concentration in the background plasma is also found to reduce the net erosion rate of high-Z materials. Both DIII-D experiments and modeling show that local 13CH4 injection can create a carbon coating on the metal surface. The profile of 13C deposition provides quantitative information on radial transport due to E × B drift and the cross-field diffusion. The deuterium gas injection upstream of the W sample can reduce W net erosion rate by plasma perturbation. The inter-ELM W erosion we measured in H-mode plasmas, rates at different radial locations are well reproduced by ERO modeling taking into account charge-state-resolved carbon ion flux in the background plasma calculated using the OEDGE code.},

  doi          = {10.1088/1741-4326/aa6451},

  journal      = {Nuclear Fusion},

  number       = 5,

  volume       = 57,

  place        = {United States},

  year         = {2017},

  month        = {3}

}

Copy to clipboard

Journal Article:

Free Publicly Available Full Text

Accepted Manuscript (DOE)

Publisher's Version of Record

DOI: 10.1088/1741-4326/aa6451

Other availability

Search WorldCat to find libraries that may hold this journal

Citation Metrics:

Cited by: 3 works

Citation information provided by
Web of Science

Figures / Tables:

Figure 1: Photographs of various samples for different experiments: (a) Mo sample for gross and net erosion measurements, (b) Mo sample after exposure with methane injection, (c) Mo sample for electrical biasing and (d) W sample after exposure with deuterium injection.

All figures and tables (8 total)

Save / Share:

Export Metadata

Save to My Library

Figures / Tables found in this record:

Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.

Similar records in OSTI.GOV collections:

Advances in understanding of high- Z material erosion and re-deposition in low- Z wall environment in DIII-D

Journal Article Ding, R. ; Rudakov, D. L. ; Stangeby, P. C. ; ... - Nuclear Fusion

Dedicated DIII-D experiments coupled with modeling reveal that the net erosion rate of high-Z materials, i.e. Mo and W, is strongly affected by carbon concentration in the plasma and the magnetic pre-sheath properties. We have investigated different methods such as electrical biasing and local gas injection to control high-Z material erosion. The net erosion rate of high-Z materials is significantly reduced due to the high local re-deposition ratio. The ERO modeling shows that the local re-deposition ratio is mainly controlled by the electric field and plasma density within the magnetic pre-sheath. The net erosion can be significantly suppressed by reducingmore »« less
Cited by 3
DOI: 10.1088/1741-4326/aa6451

Full Text Available
Advances in understanding of high- Z material erosion and re-deposition in low- Z wall environment in DIII-D

Journal Article Ding, R. ; Rudakov, D. L. ; Stangeby, P. C. ; ... - Nuclear Fusion

Dedicated DIII-D experiments coupled with modeling reveal that the net erosion rate of high- Z materials, i.e., Mo and W, is strongly affected by carbon concentration in the plasma and the magnetic pre-sheath properties. Different methods such as electrical biasing and local gas injection have been investigated to control high-Z material erosion. The net erosion rate of high-Z materials is significantly reduced due to the high local re-deposition ratio. The ERO modeling shows that the local re-deposition ratio is mainly controlled by the electric field and plasma density within the magnetic pre-sheath. The net erosion can be significantly suppressed bymore »« less
Cited by 3
DOI: 10.1088/1741-4326/aa6451

Full Text Available
Advances in understanding of high- Z material erosion and re-deposition in low- Z wall environment in DIII-D

Journal Article Ding, Rui ; Rudakov, D. L. ; Stangeby, P. C. ; ... - Nuclear Fusion

Dedicated DIII-D experiments coupled with modeling reveal that the net erosion rate of high- Z materials, i.e., Mo and W, is strongly affected by carbon concentration in the plasma and the magnetic pre-sheath properties. Different methods such as electrical biasing and local gas injection have been investigated to control high-Z material erosion. The net erosion rate of high-Z materials is significantly reduced due to the high local re-deposition ratio. The ERO modeling shows that the local re-deposition ratio is mainly controlled by the electric field and plasma density within the magnetic pre-sheath. The net erosion can be significantly suppressed bymore »« less
Cited by 3
DOI: 10.1088/1741-4326/aa6451

Full Text Available
Advances in understanding of high- Z material erosion and re-deposition in low- Z wall environment in DIII-D

Journal Article Ding, R. ; Rudakov, D. L. ; Stangeby, P. C. ; ... - Nuclear Fusion

Dedicated DIII-D experiments coupled with modeling reveal that the net erosion rate of high-Z materials, i.e. Mo and W, is strongly affected by carbon concentration in the plasma and the magnetic pre-sheath properties. Different methods such as electrical biasing and local gas injection have been investigated to control high-Z material erosion. The net erosion rate of high-Z materials is significantly reduced due to the high local re-deposition ratio. The ERO modeling shows that the local re-deposition ratio is mainly controlled by the electric field and plasma density within the magnetic pre-sheath. The net erosion can be significantly suppressed by reducingmore »« less
Cited by 3
DOI: 10.1088/1741-4326/aa6451

Full Text Available
DiMES PMI research at DIII-D in support of ITER and beyond

Journal Article Rudakov, Dimitry L. ; Abrams, Tyler ; Ding, Rui ; ... - Fusion Engineering and Design

An overview of recent Plasma-Material Interactions (PMI) research at the DIII-D tokamak using the Divertor Material Evaluation System (DiMES) is presented. The DiMES manipulator allows for exposure of material samples in the lower divertor of DIII-D under well-diagnosed ITER-relevant plasma conditions. Plasma parameters during the exposures are characterized by an extensive diagnostic suite including a number of spectroscopic diagnostics, Langmuir probes, IR imaging, and Divertor Thomson Scattering. Post-mortem measurements of net erosion/deposition on the samples are done by Ion Beam Analysis, and results are modelled by the ERO and REDEP/WBC codes with plasma background reproduced by OEDGE/DIVIMP modelling based onmore »« less
Cited by 1
DOI: 10.1016/j.fusengdes.2017.03.007

Full Text Available

Similar Records