Exploration of magnetic perturbation effects on advanced divertor configurations in NSTX-U

Frerichs, H.; Schmitz, O.; Waters, I.; Canal, G. P.; Evans, T. E.; Feng, Y.; Soukhanovskii, V. A.

doi:10.1063/1.4954816

Title: Exploration of magnetic perturbation effects on advanced divertor configurations in NSTX-U

Abstract

The control of divertor heat loads - both steady state and transient - remains a key challenge for the successful operation of ITER and FNSF. Magnetic perturbations provide a promising technique to control ELMs (transients), but understanding their detailed impact is difficult due to their symmetry breaking nature. One approach for reducing steady state heat loads are so called 'advanced divertors' which aim at optimizing the magnetic field configuration: the snowflake and the (super-)X-divertor. It is likely that both concepts - magnetic perturbations and advanced divertors - will have to work together, and we explore their inter- action based on the NSTX-U setup. An overview of different divertor con gurations under the impact of magnetic perturbations is presented, and the resulting impact on plasma edge transport is investigated with the EMC3-EIRENE code. Variations in size of the magnetic footprint of the perturbed separatrix are found, which is related to the level of flux expansion on the divertor target. Non-axisymmetric peaking of the heat flux related to the perturbed separatrix is found at the outer strike point, but only in locations where flux expansion is not too large.

Authors:

Frerichs, H. ^[1]; Schmitz, O. ^[1];

^[1]; Canal, G. P. ^[2];

^[2]; Feng, Y. ^[3]; Soukhanovskii, V. A. ^[4]

Univ. of Wisconsin, Madison, WI (United States)
General Atomics, San Diego, CA (United States)
Max Planck Inst. for Plasma Physics, Greifswald (Germany)
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Publication Date:: 2016-06-01

Research Org.:: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Sponsoring Org.:: USDOE

OSTI Identifier:: 1399721

Alternate Identifier(s):: OSTI ID: 1259743

Report Number(s):: LLNL-JRNL-739361
Journal ID: ISSN 1070-664X; TRN: US1702971

Grant/Contract Number:: AC52-07NA27344; FC02-04ER54698; SC0012315

Resource Type:: Accepted Manuscript

Journal Name:: Physics of Plasmas

Additional Journal Information:: Journal Volume: 23; Journal Issue: 6; Journal ID: ISSN 1070-664X

Publisher:: American Institute of Physics (AIP)

Country of Publication:: United States

Language:: English

Subject:: 70 PLASMA PHYSICS AND FUSION

Citation Formats


                    Frerichs, H., Schmitz, O., Waters, I., Canal, G. P., Evans, T. E., Feng, Y., and Soukhanovskii, V. A. Exploration of magnetic perturbation effects on advanced divertor configurations in NSTX-U.  United States: N. p., 2016. 
Web.  doi:10.1063/1.4954816.

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                    Frerichs, H., Schmitz, O., Waters, I., Canal, G. P., Evans, T. E., Feng, Y., & Soukhanovskii, V. A. Exploration of magnetic perturbation effects on advanced divertor configurations in NSTX-U.  United States.  https://doi.org/10.1063/1.4954816

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                    Frerichs, H., Schmitz, O., Waters, I., Canal, G. P., Evans, T. E., Feng, Y., and Soukhanovskii, V. A. Wed .  
"Exploration of magnetic perturbation effects on advanced divertor configurations in NSTX-U".  United States.  https://doi.org/10.1063/1.4954816.  https://www.osti.gov/servlets/purl/1399721.

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@article{osti_1399721,

  title        = {Exploration of magnetic perturbation effects on advanced divertor configurations in NSTX-U},

  author       = {Frerichs, H. and Schmitz, O. and Waters, I. and Canal, G. P. and Evans, T. E. and Feng, Y. and Soukhanovskii, V. A.},

  abstractNote = {The control of divertor heat loads - both steady state and transient - remains a key challenge for the successful operation of ITER and FNSF. Magnetic perturbations provide a promising technique to control ELMs (transients), but understanding their detailed impact is difficult due to their symmetry breaking nature. One approach for reducing steady state heat loads are so called 'advanced divertors' which aim at optimizing the magnetic field configuration: the snowflake and the (super-)X-divertor. It is likely that both concepts - magnetic perturbations and advanced divertors - will have to work together, and we explore their inter- action based on the NSTX-U setup. An overview of different divertor con gurations under the impact of magnetic perturbations is presented, and the resulting impact on plasma edge transport is investigated with the EMC3-EIRENE code. Variations in size of the magnetic footprint of the perturbed separatrix are found, which is related to the level of flux expansion on the divertor target. Non-axisymmetric peaking of the heat flux related to the perturbed separatrix is found at the outer strike point, but only in locations where flux expansion is not too large.},

  doi          = {10.1063/1.4954816},

  journal      = {Physics of Plasmas},

  number       = 6,

  volume       = 23,

  place        = {United States},

  year         = {2016},

  month        = {6}

}

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Figures / Tables:

FIG. 1.: Sketch of the perturbed separatrix manifolds (red and blue), and close-up of the lobe structure from oscillations around the unperturbed separatrix. Outward and inward crossing points are marked L and M, respectively.

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