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Title: Core radial electric field and transport in Wendelstein 7-X plasmas

Abstract

The results from the investigation of neoclassical core transport and the role of the radial electric field profile (Er) in the first operational phase of the Wendelstein 7-X (W7-X) stellarator are presented. In stellarator plasmas, the details of the Er profile are expected to have a strong effect on both the particle and heat fluxes. Investigation of the radial electric field is important in understanding neoclassical transport and in validation of neoclassical calculations. The radial electric field is closely related to the perpendicular plasma flow (u⊥) through the force balance equation. This allows the radial electric field to be inferred from measurements of the perpendicular flow velocity, which can be measured using the x-ray imaging crystal spectrometer and correlation reflectometry diagnostics. Large changes in the perpendicular rotation, on the order of Δu⊥~ 5 km/s (ΔEr ~12 kV/m), have been observed within a set of experiments where the heating power was stepped down from 2 MW to 0.6 MW. These experiments are examined in detail to explore the relationship between heating power temperature, and density profiles and the radial electric field. Finally, the inferred Er profiles are compared to initial neoclassical calculations based on measured plasma profiles. The results from severalmore » neoclassical codes, sfincs, fortec-3d, and dkes, are compared both with each other and the measurements. Finally, these comparisons show good agreement, giving confidence in the applicability of the neoclassical calculations to the W7-X configuration.« less

Authors:
ORCiD logo [1];  [2]; ORCiD logo [3];  [2];  [1];  [2];  [2];  [2];  [1];  [2];  [2]; ORCiD logo [1];  [2];  [1];  [2];  [2]; ORCiD logo [2]; ORCiD logo [4];  [5];  [1] more »;  [2];  [4];  [6]; ORCiD logo [1];  [2];  [7];  [2];  [6];  [2];  [2];  [3];  [2];  [2]; ORCiD logo [2]; ORCiD logo [7];  [2] « less
+ Show Author Affiliations
  1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  2. Max-Planck-Inst. fur Plasmaphysik, Greifswald (Germany)
  3. Research Centre for Energy, Environment and Technology (CIEMAT), Madrid (Spain). Lab. Nacional de Fusion
  4. Forschungszentrum Julich (Germany). Inst. fur Energie- und Klimaforschung (IEK)
  5. Univ. of Maryland, College Park, MD (United States)
  6. Auburn Univ., AL (United States)
  7. National Inst. for Fusion Science, Toki (Japan); Graduate Univ. for Advanced Studies (SOKENDAI), Toki (Japan)
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE; Euratom Research and Training Programme
Contributing Org.:
W7-X Team
OSTI Identifier:
1430535
Alternate Identifier(s):
OSTI ID: 1420217
Grant/Contract Number:  
AC02-09CH11466; FG02-93ER54197; 633053
Resource Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 25; Journal Issue: 2; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats

Pablant, N. A., Langenberg, A., Alonso, A., Beidler, C. D., Bitter, M., Bozhenkov, S., Burhenn, R., Beurskens, M., Delgado-Aparicio, L., Dinklage, A., Fuchert, G., Gates, D., Geiger, J., Hill, K. W., Hofel, U., Hirsch, M., Knauer, J., Kramer-Flecken, A., Landreman, M., Lazerson, S., MaaBberg, H., Marchuk, O., Massidda, S., Neilson, G. H., Pasch, E., Satake, S., Svennson, J., Traverso, P., Turkin, Y., Valson, P., Velasco, J. L., Weir, G., Windisch, T., Wolf, R. C., Yokoyama, M., and Zhang, D. Core radial electric field and transport in Wendelstein 7-X plasmas. United States: N. p., 2018. Web. doi:10.1063/1.4999842.
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Pablant, N. A., Langenberg, A., Alonso, A., Beidler, C. D., Bitter, M., Bozhenkov, S., Burhenn, R., Beurskens, M., Delgado-Aparicio, L., Dinklage, A., Fuchert, G., Gates, D., Geiger, J., Hill, K. W., Hofel, U., Hirsch, M., Knauer, J., Kramer-Flecken, A., Landreman, M., Lazerson, S., MaaBberg, H., Marchuk, O., Massidda, S., Neilson, G. H., Pasch, E., Satake, S., Svennson, J., Traverso, P., Turkin, Y., Valson, P., Velasco, J. L., Weir, G., Windisch, T., Wolf, R. C., Yokoyama, M., & Zhang, D. Core radial electric field and transport in Wendelstein 7-X plasmas. United States. https://doi.org/10.1063/1.4999842
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Pablant, N. A., Langenberg, A., Alonso, A., Beidler, C. D., Bitter, M., Bozhenkov, S., Burhenn, R., Beurskens, M., Delgado-Aparicio, L., Dinklage, A., Fuchert, G., Gates, D., Geiger, J., Hill, K. W., Hofel, U., Hirsch, M., Knauer, J., Kramer-Flecken, A., Landreman, M., Lazerson, S., MaaBberg, H., Marchuk, O., Massidda, S., Neilson, G. H., Pasch, E., Satake, S., Svennson, J., Traverso, P., Turkin, Y., Valson, P., Velasco, J. L., Weir, G., Windisch, T., Wolf, R. C., Yokoyama, M., and Zhang, D. Mon . "Core radial electric field and transport in Wendelstein 7-X plasmas". United States. https://doi.org/10.1063/1.4999842. https://www.osti.gov/servlets/purl/1430535.
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@article{osti_1430535,
title = {Core radial electric field and transport in Wendelstein 7-X plasmas},
author = {Pablant, N. A. and Langenberg, A. and Alonso, A. and Beidler, C. D. and Bitter, M. and Bozhenkov, S. and Burhenn, R. and Beurskens, M. and Delgado-Aparicio, L. and Dinklage, A. and Fuchert, G. and Gates, D. and Geiger, J. and Hill, K. W. and Hofel, U. and Hirsch, M. and Knauer, J. and Kramer-Flecken, A. and Landreman, M. and Lazerson, S. and MaaBberg, H. and Marchuk, O. and Massidda, S. and Neilson, G. H. and Pasch, E. and Satake, S. and Svennson, J. and Traverso, P. and Turkin, Y. and Valson, P. and Velasco, J. L. and Weir, G. and Windisch, T. and Wolf, R. C. and Yokoyama, M. and Zhang, D.},
abstractNote = {The results from the investigation of neoclassical core transport and the role of the radial electric field profile (Er) in the first operational phase of the Wendelstein 7-X (W7-X) stellarator are presented. In stellarator plasmas, the details of the Er profile are expected to have a strong effect on both the particle and heat fluxes. Investigation of the radial electric field is important in understanding neoclassical transport and in validation of neoclassical calculations. The radial electric field is closely related to the perpendicular plasma flow (u⊥) through the force balance equation. This allows the radial electric field to be inferred from measurements of the perpendicular flow velocity, which can be measured using the x-ray imaging crystal spectrometer and correlation reflectometry diagnostics. Large changes in the perpendicular rotation, on the order of Δu⊥~ 5 km/s (ΔEr ~12 kV/m), have been observed within a set of experiments where the heating power was stepped down from 2 MW to 0.6 MW. These experiments are examined in detail to explore the relationship between heating power temperature, and density profiles and the radial electric field. Finally, the inferred Er profiles are compared to initial neoclassical calculations based on measured plasma profiles. The results from several neoclassical codes, sfincs, fortec-3d, and dkes, are compared both with each other and the measurements. Finally, these comparisons show good agreement, giving confidence in the applicability of the neoclassical calculations to the W7-X configuration.},
doi = {10.1063/1.4999842},
journal = {Physics of Plasmas},
number = 2,
volume = 25,
place = {United States},
year = {Mon Feb 12 00:00:00 EST 2018},
month = {Mon Feb 12 00:00:00 EST 2018}
}
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https://doi.org/10.1063/1.4999842
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Cited by: 42 works
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Figures / Tables:

FIG. 1. FIG. 1. : Viewing geometry of the the XICS diagnostic on W7-X.
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Works referenced in this record:

Tomographic inversion techniques incorporating physical constraints for line integrated spectroscopy in stellarators and tokamaks
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Poloidal correlation reflectometry at W7-X: radial electric field and coherent fluctuations
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Enhanced heat confinement in the flexible heliac TJ-II
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Measurement and calculation of the radial electric field in the stellarator W7-AS
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Major results from the first plasma campaign of the Wendelstein 7-X stellarator
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    Works referencing / citing this record:

    Magnetic configuration effects on the Wendelstein 7-X stellarator
    journal, May 2018

    Prospects of X-ray imaging spectrometers for impurity transport: Recent results from the stellarator Wendelstein 7-X (invited)
    journal, October 2018

    • Langenberg, A.; Pablant, N. A.; Wegner, Th.
    • Review of Scientific Instruments, Vol. 89, Issue 10
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    In situ wavelength calibration system for the X-ray Imaging Crystal Spectrometer (XICS) on W7-X
    journal, October 2018

    • Kring, J.; Pablant, N.; Langenberg, A.
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    • DOI: 10.1063/1.5038809

    Inference of temperature and density profiles via forward modeling of an x-ray imaging crystal spectrometer within the Minerva Bayesian analysis framework
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    • Langenberg, A.; Svensson, J.; Marchuk, O.
    • Review of Scientific Instruments, Vol. 90, Issue 6
    • DOI: 10.1063/1.5086283

    Collective Thomson scattering model for arbitrarily drifting bi-Maxwellian velocity distributions
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    • Abramovic, I.; Salewski, M.; Moseev, D.
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    Comparison of a 2D nonlocal transport model to ECRH experiments in LHD
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    • Maggs, J. E.; Morales, G. J.
    • Physics of Plasmas, Vol. 26, Issue 5
    • DOI: 10.1063/1.5089461

    Performance of Wendelstein 7-X stellarator plasmas during the first divertor operation phase
    journal, August 2019

    • Wolf, R. C.; Alonso, A.; Äkäslompolo, S.
    • Physics of Plasmas, Vol. 26, Issue 8
    • DOI: 10.1063/1.5098761

    Charge exchange recombination spectroscopy at Wendelstein 7-X
    journal, February 2020

    • Ford, O. P.; Vanó, L.; Alonso, J. A.
    • Review of Scientific Instruments, Vol. 91, Issue 2
    • DOI: 10.1063/1.5132936

    Impurity transport studies at Wendelstein 7-X by means of x-ray imaging spectrometer measurements
    journal, November 2018

    • Langenberg, A.; Warmer, F.; Fuchert, G.
    • Plasma Physics and Controlled Fusion, Vol. 61, Issue 1
    • DOI: 10.1088/1361-6587/aaeb74

    Intermittence and turbulence in fusion devices
    journal, December 2019

    • Carreras, B. A.; García, L.; Nicolau, J. H.
    • Plasma Physics and Controlled Fusion, Vol. 62, Issue 2
    • DOI: 10.1088/1361-6587/ab57f9

    Energy confinement of hydrogen and deuterium electron-root plasmas in the Large Helical Device
    journal, August 2018

    Global energy confinement in the initial limiter configuration of Wendelstein 7-X
    journal, August 2018

    The role of neutral friction in governing parallel flows in the HSX stellarator
    journal, February 2019

    Overview of recent TJ-II stellarator results
    journal, July 2019

    Asymmetry of parallel flow on the Large Helical Device
    journal, September 2019

    Overview of recent TJ-II stellarator results
    text, January 2019

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