Electron pressure balance in the SOL through the transition to detachment

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

doi:10.1016/j.jnucmat.2015.01.066

Electron pressure balance in the SOL through the transition to detachment

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

Fusion Engineering

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Abstract

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 L_parallel demonstrate a rapid transition from T_e ≥ 15 eV to le;3 eV occurring both at the outer strike point and upstream of the X-point. These observations provide a strong benchmark for ongoing modeling of divertor detachment for existing and future tokamak devices.

Original language	English
Article number	48926
Pages (from-to)	533-536
Number of pages	4
Journal	Journal of Nuclear Materials
Volume	463
DOIs	https://doi.org/10.1016/j.jnucmat.2015.01.066
State	Published - Jul 22 2015

Funding

This work was supported in part under the auspices of the US Department of Energy (DOE) by LLNL under DE-AC52-07NA27344 and by the US DOE under DE-FC02-04ER54698 , DE-FG02-07ER54917 , DE-AC05-00OR22725 , and DE-AC04-94AL85000 . DIII-D data shown in this paper can be obtained in digital format by following the links at https://fusion.gat.com/global/D3D_DMP .

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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., ... Watkins, J. G. (2015). Electron pressure balance in the SOL through the transition to detachment. Journal of Nuclear Materials, 463, 533-536. Article 48926. https://doi.org/10.1016/j.jnucmat.2015.01.066

@article{d8670785179b4a54a5d215edd72df4f6,

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

abstract = "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 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 le;3 eV occurring both at the outer strike point and upstream of the X-point. These observations provide a strong benchmark for ongoing modeling of divertor detachment for existing and future tokamak devices.",

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

note = "Publisher Copyright: {\textcopyright} 2015 Elsevier B.V.",

year = "2015",

month = jul,

day = "22",

doi = "10.1016/j.jnucmat.2015.01.066",

language = "English",

volume = "463",

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McLean, AG, Leonard, AW, Makowski, MA, Groth, M, Allen, SL, Boedo, JA, Bray, BD, Briesemeister, AR, Carlstrom, TN, Eldon, D, Fenstermacher, ME, Hill, DN, Lasnier, CJ, Liu, C, Osborne, TH, Petrie, TW, Soukhanovskii, VA, Stangeby, PC, Tsui, C, Unterberg, EA & Watkins, JG 2015, 'Electron pressure balance in the SOL through the transition to detachment', Journal of Nuclear Materials, vol. 463, 48926, pp. 533-536. https://doi.org/10.1016/j.jnucmat.2015.01.066

TY - JOUR

T1 - Electron pressure balance in the SOL through the transition to detachment

AU - McLean, A. G.

AU - Leonard, A. W.

AU - Makowski, M. A.

AU - Groth, M.

AU - Allen, S. L.

AU - Boedo, J. A.

AU - Bray, B. D.

AU - Briesemeister, A. R.

AU - Carlstrom, T. N.

AU - Eldon, D.

AU - Fenstermacher, M. E.

AU - Hill, D. N.

AU - Lasnier, C. J.

AU - Liu, C.

AU - Osborne, T. H.

AU - Petrie, T. W.

AU - Soukhanovskii, V. A.

AU - Stangeby, P. C.

AU - Tsui, C.

AU - Unterberg, E. A.

AU - Watkins, J. G.

PY - 2015/7/22

Y1 - 2015/7/22

N2 - 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 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 le;3 eV occurring both at the outer strike point and upstream of the X-point. These observations provide a strong benchmark for ongoing modeling of divertor detachment for existing and future tokamak devices.

AB - 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 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 le;3 eV occurring both at the outer strike point and upstream of the X-point. These observations provide a strong benchmark for ongoing modeling of divertor detachment for existing and future tokamak devices.

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U2 - 10.1016/j.jnucmat.2015.01.066

DO - 10.1016/j.jnucmat.2015.01.066

M3 - Article

AN - SCOPUS:84937739401

SN - 0022-3115

VL - 463

SP - 533

EP - 536

JO - Journal of Nuclear Materials

JF - Journal of Nuclear Materials

M1 - 48926

ER -

Electron pressure balance in the SOL through the transition to detachment

Abstract

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