Electron pressure balance in the SOL through the transition to detachment

McLean, A. G.; Leonard, A. W.; Makowski, M. A.; Groth, M.; Allen, S. L.; Boedo, J. A.; Bray, B. D.; Briesemeister, A. R.; Carlstrom, T. N.; Eldon, D.; Fenstermacher, M. E.; Hill, D. N.; Lasnier, C. J.; Liu, C.; Osborne, T. H.; Petrie, T. W.; Soukhanovskii, V. A.; Stangeby, P. C.; Tsui, C.; Unterberg, E. A.; Watkins, J. G.

doi:10.1016/j.jnucmat.2015.01.066

Title: Electron pressure balance in the SOL through the transition to detachment

Abstract

Upgrades to core and divertor Thomson scattering (DTS) diagnostics at DIII-D have provided measurements of electron pressure profiles in the lower divertor from attached- to fully-detached divertor plasma conditions. Detailed, multistep sequences of discharges with increasing line-averaged density were run at several levels of P_inj. Strike point sweeping allowed 2D divertor characterization using DTS optimized to measure T_e down to 0.5 eV. The ionization front at the onset of detachment is found to move upwards in a controlled manner consistent with the indication that scrape-off layer parallel power flux is converted from conducted to convective heat transport. Measurements of n_e, T_e and p_e in the divertor versus Lparallel demonstrate a rapid transition from Te ≥ 15 eV to ≤3 eV occurring both at the outer strike point and upstream of the X-point. Furthermore, these observations provide a strong benchmark for ongoing modeling of divertor detachment for existing and future tokamak devices.

Authors:

McLean, A. G. ^[1]; Leonard, A. W. ^[2]; Makowski, M. A. ^[2]; Groth, M. ^[3]; Allen, S. L. ^[1]; Boedo, J. A. ^[4]; Bray, B. D. ^[2]; Briesemeister, A. R. ^[5]; Carlstrom, T. N. ^[1]; Eldon, D. ^[4]; Fenstermacher, M. E. ^[1]; Hill, D. N. ^[1]; Lasnier, C. J. ^[1]; Liu, C. ^[2]; Osborne, T. H. ^[2]; Petrie, T. W. ^[2]; Soukhanovskii, V. A. ^[1]; Stangeby, P. C. ^[6]; Tsui, C. ^[6]; Unterberg, E. A. ^[5] more »

Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
General Atomics, San Diego, CA (United States)
Aalto Univ., Espoo (Finland)
Univ. of California San Diego, La Jolla, CA (United States)
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Univ. of Toronto Institute for Aerospace Studies, Toronto (Canada)
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Publication Date:: Sat Feb 07 00:00:00 EST 2015

Research Org.:: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:: USDOE Office of Science (SC)

OSTI Identifier:: 1265737

Alternate Identifier(s):: OSTI ID: 1252232

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

Resource Type:: Accepted Manuscript

Journal Name:: Journal of Nuclear Materials

Additional Journal Information:: Journal Volume: 463; Journal Issue: C; Journal ID: ISSN 0022-3115

Publisher:: Elsevier

Country of Publication:: United States

Language:: English

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats


                    McLean, A. G., Leonard, A. W., Makowski, M. A., Groth, M., Allen, S. L., Boedo, J. A., Bray, B. D., Briesemeister, A. R., Carlstrom, T. N., Eldon, D., Fenstermacher, M. E., Hill, D. N., Lasnier, C. J., Liu, C., Osborne, T. H., Petrie, T. W., Soukhanovskii, V. A., Stangeby, P. C., Tsui, C., Unterberg, E. A., and Watkins, J. G. Electron pressure balance in the SOL through the transition to detachment.  United States: N. p., 2015. 
Web.  doi:10.1016/j.jnucmat.2015.01.066.

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                    McLean, A. G., Leonard, A. W., Makowski, M. A., Groth, M., Allen, S. L., Boedo, J. A., Bray, B. D., Briesemeister, A. R., Carlstrom, T. N., Eldon, D., Fenstermacher, M. E., Hill, D. N., Lasnier, C. J., Liu, C., Osborne, T. H., Petrie, T. W., Soukhanovskii, V. A., Stangeby, P. C., Tsui, C., Unterberg, E. A., & Watkins, J. G. Electron pressure balance in the SOL through the transition to detachment.  United States.  https://doi.org/10.1016/j.jnucmat.2015.01.066

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                    McLean, A. G., Leonard, A. W., Makowski, M. A., Groth, M., Allen, S. L., Boedo, J. A., Bray, B. D., Briesemeister, A. R., Carlstrom, T. N., Eldon, D., Fenstermacher, M. E., Hill, D. N., Lasnier, C. J., Liu, C., Osborne, T. H., Petrie, T. W., Soukhanovskii, V. A., Stangeby, P. C., Tsui, C., Unterberg, E. A., and Watkins, J. G. Sat .  
"Electron pressure balance in the SOL through the transition to detachment".  United States.  https://doi.org/10.1016/j.jnucmat.2015.01.066.  https://www.osti.gov/servlets/purl/1265737.

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@article{osti_1265737,

  title        = {Electron pressure balance in the SOL through the transition to detachment},

  author       = {McLean, A. G. and Leonard, A. W. and Makowski, M. A. and Groth, M. and Allen, S. L. and Boedo, J. A. and Bray, B. D. and Briesemeister, A. R. and Carlstrom, T. N. and Eldon, D. and Fenstermacher, M. E. and Hill, D. N. and Lasnier, C. J. and Liu, C. and Osborne, T. H. and Petrie, T. W. and Soukhanovskii, V. A. and Stangeby, P. C. and Tsui, C. and Unterberg, E. A. and Watkins, J. G.},

  abstractNote = {Upgrades to core and divertor Thomson scattering (DTS) diagnostics at DIII-D have provided measurements of electron pressure profiles in the lower divertor from attached- to fully-detached divertor plasma conditions. Detailed, multistep sequences of discharges with increasing line-averaged density were run at several levels of Pinj. Strike point sweeping allowed 2D divertor characterization using DTS optimized to measure Te down to 0.5 eV. The ionization front at the onset of detachment is found to move upwards in a controlled manner consistent with the indication that scrape-off layer parallel power flux is converted from conducted to convective heat transport. Measurements of ne, Te and pe in the divertor versus Lparallel demonstrate a rapid transition from Te ≥ 15 eV to ≤3 eV occurring both at the outer strike point and upstream of the X-point. Furthermore, these observations provide a strong benchmark for ongoing modeling of divertor detachment for existing and future tokamak devices.},

  doi          = {10.1016/j.jnucmat.2015.01.066},

  journal      = {Journal of Nuclear Materials},

  number       = C,

  volume       = 463,

  place        = {United States},

  year         = {Sat Feb 07 00:00:00 EST 2015},

  month        = {Sat Feb 07 00:00:00 EST 2015}

}

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Works referenced in this record:

Initial operation of the divertor Thomson scattering diagnostic on DIII-D
journal, February 1997

Carlstrom, T. N.; Hsieh, C. L.; Stockdale, R.
Review of Scientific Instruments, Vol. 68, Issue 2
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Plasma detachment in JET Mark I divertor experiments
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Loarte, A.; Monk, R. D.; Martín-Solís, J. R.
Nuclear Fusion, Vol. 38, Issue 3
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Initial results of the high resolution edge Thomson scattering upgrade at DIII-D
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Eldon, D.; Bray, B. D.; Deterly, T. M.
Review of Scientific Instruments, Vol. 83, Issue 10
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Plasma pressure and flows during divertor detachment
journal, March 1999

Schaffer, M. J.; Boedo, J. A.; Moyer, R. A.
Journal of Nuclear Materials, Vol. 266-269
DOI: 10.1016/S0022-3115(98)00528-5

The Filterscope
journal, March 2003

Colchin, R. J.; Hillis, D. L.; Maingi, R.
Review of Scientific Instruments, Vol. 74, Issue 3
DOI: 10.1063/1.1537038

Scaling radiative divertor solutions to high power in DIII-D
journal, April 2012

Leonard, A. W.; Mahdavi, M. A.; Lasnier, C. J.
Nuclear Fusion, Vol. 52, Issue 6
DOI: 10.1088/0029-5515/52/6/063015

Current understanding of divertor detachment: Experiments and modelling
journal, June 2009

Wischmeier, M.; Groth, M.; Kallenbach, A.
Journal of Nuclear Materials, Vol. 390-391
DOI: 10.1016/j.jnucmat.2009.01.081

Investigation of electron parallel pressure balance in the scrapeoff layer of deuterium-based radiative divertor discharges in DIII-D
journal, February 1997

Petrie, T.
Journal of Nuclear Materials, Vol. 241-243, Issue 1
DOI: 10.1016/S0022-3115(96)00579-X

Poloidal distribution of recycling sources and core plasma fueling in DIII-D, ASDEX-Upgrade and JET L-mode plasmas
journal, November 2011

Groth, M.; Porter, G. D.; Rognlien, T. D.
Plasma Physics and Controlled Fusion, Vol. 53, Issue 12
DOI: 10.1088/0741-3335/53/12/124017

Works referencing / citing this record:

Compatibility of separatrix density scaling for divertor detachment with H-mode pedestal operation in DIII-D
journal, July 2017

Leonard, A. W.; McLean, A. G.; Makowski, M. A.
Nuclear Fusion, Vol. 57, Issue 8
DOI: 10.1088/1741-4326/aa778c

Divertor impurity seeding experiments at the COMPASS tokamak
journal, September 2019

Komm, M.; Khodunov, I.; Cavalier, J.
Nuclear Fusion, Vol. 59, Issue 10
DOI: 10.1088/1741-4326/ab34d2

The role of particle, energy and momentum losses in 1D simulations of divertor detachment
text, January 2018

Dudson, B. D.; Allen, J.; Body, T.
arXiv
DOI: 10.48550/arxiv.1812.09402

Testing the role of molecular physics in dissipative divertor operations through helium plasmas at DIII-D
journal, May 2017

Canik, J. M.; Briesemeister, A. R.; McLean, A. G.
Physics of Plasmas, Vol. 24, Issue 5
DOI: 10.1063/1.4982057

Controlling marginally detached divertor plasmas
journal, May 2017

Eldon, D.; Kolemen, E.; Barton, J. L.
Nuclear Fusion, Vol. 57, Issue 6
DOI: 10.1088/1741-4326/aa6b16

The role of particle, energy and momentum losses in 1D simulations of divertor detachment
journal, May 2019

Dudson, B. D.; Allen, J.; Body, T.
Plasma Physics and Controlled Fusion, Vol. 61, Issue 6
DOI: 10.1088/1361-6587/ab1321

First experimental tests of a new small angle slot divertor on DIII-D
journal, July 2019

Guo, H. Y.; Wang, H. Q.; Watkins, J. G.
Nuclear Fusion, Vol. 59, Issue 8
DOI: 10.1088/1741-4326/ab26ee

Developing physics basis for the snowflake divertor in the DIII-D tokamak
journal, February 2018

Soukhanovskii, V. A.; Allen, S. L.; Fenstermacher, M. E.
Nuclear Fusion, Vol. 58, Issue 3
DOI: 10.1088/1741-4326/aaa6de

A review of direct experimental measurements of detachment
journal, February 2018

Boedo, J.; McLean, A. G.; Rudakov, D. L.
Plasma Physics and Controlled Fusion, Vol. 60, Issue 4
DOI: 10.1088/1361-6587/aaa2ec

Plasma detachment in divertor tokamaks
journal, February 2018

Leonard, A. W.
Plasma Physics and Controlled Fusion, Vol. 60, Issue 4
DOI: 10.1088/1361-6587/aaa7a9

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Title: Electron pressure balance in the SOL through the transition to detachment

Abstract

Citation Formats

Initial operation of the divertor Thomson scattering diagnostic on DIII-D journal, February 1997

Plasma detachment in JET Mark I divertor experiments journal, March 1998

Initial results of the high resolution edge Thomson scattering upgrade at DIII-D journal, October 2012

Plasma pressure and flows during divertor detachment journal, March 1999

The Filterscope journal, March 2003

Scaling radiative divertor solutions to high power in DIII-D journal, April 2012

Current understanding of divertor detachment: Experiments and modelling journal, June 2009

Investigation of electron parallel pressure balance in the scrapeoff layer of deuterium-based radiative divertor discharges in DIII-D journal, February 1997

Poloidal distribution of recycling sources and core plasma fueling in DIII-D, ASDEX-Upgrade and JET L-mode plasmas journal, November 2011

Compatibility of separatrix density scaling for divertor detachment with H-mode pedestal operation in DIII-D journal, July 2017

Divertor impurity seeding experiments at the COMPASS tokamak journal, September 2019

The role of particle, energy and momentum losses in 1D simulations of divertor detachment text, January 2018

Testing the role of molecular physics in dissipative divertor operations through helium plasmas at DIII-D journal, May 2017

Controlling marginally detached divertor plasmas journal, May 2017

The role of particle, energy and momentum losses in 1D simulations of divertor detachment journal, May 2019

First experimental tests of a new small angle slot divertor on DIII-D journal, July 2019

Developing physics basis for the snowflake divertor in the DIII-D tokamak journal, February 2018

A review of direct experimental measurements of detachment journal, February 2018

Plasma detachment in divertor tokamaks journal, February 2018

Initial operation of the divertor Thomson scattering diagnostic on DIII-D
journal, February 1997

Plasma detachment in JET Mark I divertor experiments
journal, March 1998

Initial results of the high resolution edge Thomson scattering upgrade at DIII-D
journal, October 2012

Plasma pressure and flows during divertor detachment
journal, March 1999

The Filterscope
journal, March 2003

Scaling radiative divertor solutions to high power in DIII-D
journal, April 2012

Current understanding of divertor detachment: Experiments and modelling
journal, June 2009

Investigation of electron parallel pressure balance in the scrapeoff layer of deuterium-based radiative divertor discharges in DIII-D
journal, February 1997

Poloidal distribution of recycling sources and core plasma fueling in DIII-D, ASDEX-Upgrade and JET L-mode plasmas
journal, November 2011

Compatibility of separatrix density scaling for divertor detachment with H-mode pedestal operation in DIII-D
journal, July 2017

Divertor impurity seeding experiments at the COMPASS tokamak
journal, September 2019

The role of particle, energy and momentum losses in 1D simulations of divertor detachment
text, January 2018

Testing the role of molecular physics in dissipative divertor operations through helium plasmas at DIII-D
journal, May 2017

Controlling marginally detached divertor plasmas
journal, May 2017

The role of particle, energy and momentum losses in 1D simulations of divertor detachment
journal, May 2019

First experimental tests of a new small angle slot divertor on DIII-D
journal, July 2019

Developing physics basis for the snowflake divertor in the DIII-D tokamak
journal, February 2018

A review of direct experimental measurements of detachment
journal, February 2018

Plasma detachment in divertor tokamaks
journal, February 2018