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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:
 [1];  [1]; ORCiD logo [1];  [2]; ORCiD logo [2];  [3];  [4]
  1. Univ. of Wisconsin, Madison, WI (United States)
  2. General Atomics, San Diego, CA (United States)
  3. Max Planck Inst. for Plasma Physics, Greifswald (Germany)
  4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (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.
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. doi:10.1063/1.4954816.
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. doi:10.1063/1.4954816. https://www.osti.gov/servlets/purl/1399721.
@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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Free Publicly Available Full Text
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Cited by: 3 works
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Figures / Tables:

FIG. 1. 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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Works referenced in this record:

Geometrical properties of a “snowflake” divertor
journal, June 2007


On heat loading, novel divertors, and fusion reactors
journal, July 2007

  • Kotschenreuther, M.; Valanju, P. M.; Mahajan, S. M.
  • Physics of Plasmas, Vol. 14, Issue 7
  • DOI: 10.1063/1.2739422

The pattern of parallel edge plasma flows due to pressure gradients, recycling, and resonant magnetic perturbations in DIII-D
journal, July 2015

  • Frerichs, H.; Schmitz, O.; Evans, T.
  • Physics of Plasmas, Vol. 22, Issue 7
  • DOI: 10.1063/1.4926524

Three-dimensional edge transport simulations for DIII-D plasmas with resonant magnetic perturbations
journal, February 2010


Effect of nonaxisymmetric magnetic perturbations on divertor heat and particle flux profiles in National Spherical Torus Experiment
journal, May 2011

  • Ahn, J-W.; Maingi, R.; Canik, J. M.
  • Physics of Plasmas, Vol. 18, Issue 5
  • DOI: 10.1063/1.3574522

Magnetic geometry and physics of advanced divertors: The X-divertor and the snowflake
journal, October 2013

  • Kotschenreuther, Mike; Valanju, Prashant; Covele, Brent
  • Physics of Plasmas, Vol. 20, Issue 10
  • DOI: 10.1063/1.4824735

Progress on the application of ELM control schemes to ITER scenarios from the non-active phase to DT operation
journal, February 2014


The magnetic field structure of a snowflake divertor
journal, September 2008

  • Ryutov, D. D.; Cohen, R. H.; Rognlien, T. D.
  • Physics of Plasmas, Vol. 15, Issue 9
  • DOI: 10.1063/1.2967900

Resonant magnetic perturbations of edge-plasmas in toroidal confinement devices
journal, November 2015


Local properties of the magnetic field in a snowflake divertor
journal, August 2010


Comment on “Magnetic geometry and physics of advanced divertors: The X-divertor and the snowflake” [Phys. Plasmas 20 , 102507 (2013)]
journal, May 2014

  • Ryutov, D. D.; Cohen, R. H.; Rognlien, T. D.
  • Physics of Plasmas, Vol. 21, Issue 5
  • DOI: 10.1063/1.4873404

Response to “Comment on ‘Magnetic geometry and physics of advanced divertors: The X-divertor and the snowflake’ ” [Phys. Plasmas 21 , 054701 (2014)]
journal, May 2014

  • Kotschenreuther, Mike; Valanju, Prashant; Covele, Brent
  • Physics of Plasmas, Vol. 21, Issue 5
  • DOI: 10.1063/1.4873405

Overview of the physics and engineering design of NSTX upgrade
journal, July 2012


On Demand Triggering of Edge Localized Instabilities Using External Nonaxisymmetric Magnetic Perturbations in Toroidal Plasmas
journal, January 2010


3D Edge Modeling and Island Divertor Physics
journal, April 2004

  • Feng, Y.; Sardei, F.; Kisslinger, J.
  • Contributions to Plasma Physics, Vol. 44, Issue 13
  • DOI: 10.1002/ctpp.200410009

Method for comparison of tokamak divertor strike point data with magnetic perturbation models
journal, May 2014


Aspects of three dimensional transport for ELM control experiments in ITER-similar shape plasmas at low collisionality in DIII-D
journal, November 2008


Recent Improvements in the EMC3-Eirene Code: Recent Improvements in the EMC3-Eirene Code
journal, June 2014

  • Feng, Y.; Frerichs, H.; Kobayashi, M.
  • Contributions to Plasma Physics, Vol. 54, Issue 4-6
  • DOI: 10.1002/ctpp.201410092

First Observation of Edge Localized Modes Mitigation with Resonant and Nonresonant Magnetic Perturbations in ASDEX Upgrade
journal, June 2011


Active Control of Type-I Edge-Localized Modes with n = 1 Perturbation Fields in the JET Tokamak
journal, June 2007


A helical magnetic limiter for boundary layer control in large tokamaks
journal, June 1981


Stability and control of iterated non-linear transport solvers for fusion edge plasmas
journal, March 2015


Implementation of the 3D edge plasma code EMC3-EIRENE on NSTX
journal, May 2012


Super-X divertors and high power density fusion devices
journal, May 2009

  • Valanju, P. M.; Kotschenreuther, M.; Mahajan, S. M.
  • Physics of Plasmas, Vol. 16, Issue 5
  • DOI: 10.1063/1.3110984

First EMC3-Eirene simulations of the TCV snowflake divertor
journal, February 2014


Edge stability and transport control with resonant magnetic perturbations in collisionless tokamak plasmas
journal, May 2006

  • Evans, Todd E.; Moyer, Richard A.; Burrell, Keith H.
  • Nature Physics, Vol. 2, Issue 6
  • DOI: 10.1038/nphys312

Formation of a three-dimensional plasma boundary after decay of the plasma response to resonant magnetic perturbation fields
journal, December 2013


Experimental signatures of homoclinic tangles in poloidally diverted tokamaks
journal, January 2005


Influence of an ergodic magnetic limiter on the impurity content in a tokamak
journal, September 1978


Homoclinic tangles, bifurcations and edge stochasticity in diverted tokamaks
journal, April 2004

  • Evans, T. E.; Roeder, R. K. W.; Carter, J. A.
  • Contributions to Plasma Physics, Vol. 44, Issue 13
  • DOI: 10.1002/ctpp.200410034

Block-structured grids in Lagrangian 3D edge plasma transport simulations
journal, January 2010


A simple highly accurate field-line mapping technique for three-dimensional Monte Carlo modeling of plasma edge transport
journal, May 2005

  • Feng, Y.; Sardei, F.; Kisslinger, J.
  • Physics of Plasmas, Vol. 12, Issue 5
  • DOI: 10.1063/1.1888959

Importance of plasma response to nonaxisymmetric perturbations in tokamaks
journal, May 2009

  • Park, Jong-kyu; Boozer, Allen H.; Menard, Jonathan E.
  • Physics of Plasmas, Vol. 16, Issue 5
  • DOI: 10.1063/1.3122862

3D vacuum magnetic field modelling of the ITER ELM control coil during standard operating scenarios
journal, August 2013


Exploration of magnetic perturbation effects on advanced divertor configurations in NSTX-U
dataset, January 2016

  • Frerichs, H.; Waters, I.; Schmitz, O.
  • Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
  • DOI: 10.11578/1366498

Exploration of magnetic perturbation effects on advanced divertor configurations in NSTX-U
dataset, January 2016

  • Frerichs, H.; Waters, I.; Schmitz, O.
  • Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
  • DOI: 10.11578/1366498

Exploration of magnetic perturbation effects on advanced divertor configurations in NSTX-U
dataset, January 2016

  • Frerichs, H.; Waters, I.; Schmitz, O.
  • Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
  • DOI: 10.11578/1562062

    Works referencing / citing this record:

    Exploration of magnetic perturbation effects on advanced divertor configurations in NSTX-U
    dataset, January 2016

    • Frerichs, H.; Waters, I.; Schmitz, O.
    • Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
    • DOI: 10.11578/1366498

    3D Edge Modeling and Island Divertor Physics
    journal, April 2004

    • Feng, Y.; Sardei, F.; Kisslinger, J.
    • Contributions to Plasma Physics, Vol. 44, Issue 13
    • DOI: 10.1002/ctpp.200410009

    Homoclinic tangles, bifurcations and edge stochasticity in diverted tokamaks
    journal, April 2004

    • Evans, T. E.; Roeder, R. K. W.; Carter, J. A.
    • Contributions to Plasma Physics, Vol. 44, Issue 13
    • DOI: 10.1002/ctpp.200410034

    Recent Improvements in the EMC3-Eirene Code: Recent Improvements in the EMC3-Eirene Code
    journal, June 2014

    • Feng, Y.; Frerichs, H.; Kobayashi, M.
    • Contributions to Plasma Physics, Vol. 54, Issue 4-6
    • DOI: 10.1002/ctpp.201410092

    Influence of an ergodic magnetic limiter on the impurity content in a tokamak
    journal, September 1978


    Block-structured grids in Lagrangian 3D edge plasma transport simulations
    journal, January 2010


    Stability and control of iterated non-linear transport solvers for fusion edge plasmas
    journal, March 2015


    Edge stability and transport control with resonant magnetic perturbations in collisionless tokamak plasmas
    journal, May 2006

    • Evans, Todd E.; Moyer, Richard A.; Burrell, Keith H.
    • Nature Physics, Vol. 2, Issue 6
    • DOI: 10.1038/nphys312

    A simple highly accurate field-line mapping technique for three-dimensional Monte Carlo modeling of plasma edge transport
    journal, May 2005

    • Feng, Y.; Sardei, F.; Kisslinger, J.
    • Physics of Plasmas, Vol. 12, Issue 5
    • DOI: 10.1063/1.1888959

    Geometrical properties of a “snowflake” divertor
    journal, June 2007


    On heat loading, novel divertors, and fusion reactors
    journal, July 2007

    • Kotschenreuther, M.; Valanju, P. M.; Mahajan, S. M.
    • Physics of Plasmas, Vol. 14, Issue 7
    • DOI: 10.1063/1.2739422

    The magnetic field structure of a snowflake divertor
    journal, September 2008

    • Ryutov, D. D.; Cohen, R. H.; Rognlien, T. D.
    • Physics of Plasmas, Vol. 15, Issue 9
    • DOI: 10.1063/1.2967900

    Super-X divertors and high power density fusion devices
    journal, May 2009

    • Valanju, P. M.; Kotschenreuther, M.; Mahajan, S. M.
    • Physics of Plasmas, Vol. 16, Issue 5
    • DOI: 10.1063/1.3110984

    Importance of plasma response to nonaxisymmetric perturbations in tokamaks
    journal, May 2009

    • Park, Jong-kyu; Boozer, Allen H.; Menard, Jonathan E.
    • Physics of Plasmas, Vol. 16, Issue 5
    • DOI: 10.1063/1.3122862

    Effect of nonaxisymmetric magnetic perturbations on divertor heat and particle flux profiles in National Spherical Torus Experiment
    journal, May 2011

    • Ahn, J-W.; Maingi, R.; Canik, J. M.
    • Physics of Plasmas, Vol. 18, Issue 5
    • DOI: 10.1063/1.3574522

    Magnetic geometry and physics of advanced divertors: The X-divertor and the snowflake
    journal, October 2013

    • Kotschenreuther, Mike; Valanju, Prashant; Covele, Brent
    • Physics of Plasmas, Vol. 20, Issue 10
    • DOI: 10.1063/1.4824735

    Comment on “Magnetic geometry and physics of advanced divertors: The X-divertor and the snowflake” [Phys. Plasmas 20 , 102507 (2013)]
    journal, May 2014

    • Ryutov, D. D.; Cohen, R. H.; Rognlien, T. D.
    • Physics of Plasmas, Vol. 21, Issue 5
    • DOI: 10.1063/1.4873404

    Response to “Comment on ‘Magnetic geometry and physics of advanced divertors: The X-divertor and the snowflake’ ” [Phys. Plasmas 21 , 054701 (2014)]
    journal, May 2014

    • Kotschenreuther, Mike; Valanju, Prashant; Covele, Brent
    • Physics of Plasmas, Vol. 21, Issue 5
    • DOI: 10.1063/1.4873405

    The pattern of parallel edge plasma flows due to pressure gradients, recycling, and resonant magnetic perturbations in DIII-D
    journal, July 2015

    • Frerichs, H.; Schmitz, O.; Evans, T.
    • Physics of Plasmas, Vol. 22, Issue 7
    • DOI: 10.1063/1.4926524

    A helical magnetic limiter for boundary layer control in large tokamaks
    journal, June 1981


    Three-dimensional edge transport simulations for DIII-D plasmas with resonant magnetic perturbations
    journal, February 2010


    Implementation of the 3D edge plasma code EMC3-EIRENE on NSTX
    journal, May 2012


    Overview of the physics and engineering design of NSTX upgrade
    journal, July 2012


    3D vacuum magnetic field modelling of the ITER ELM control coil during standard operating scenarios
    journal, August 2013


    Formation of a three-dimensional plasma boundary after decay of the plasma response to resonant magnetic perturbation fields
    journal, December 2013


    Progress on the application of ELM control schemes to ITER scenarios from the non-active phase to DT operation
    journal, February 2014


    Method for comparison of tokamak divertor strike point data with magnetic perturbation models
    journal, May 2014


    Aspects of three dimensional transport for ELM control experiments in ITER-similar shape plasmas at low collisionality in DIII-D
    journal, November 2008


    Local properties of the magnetic field in a snowflake divertor
    journal, August 2010


    First EMC3-Eirene simulations of the TCV snowflake divertor
    journal, February 2014


    Resonant magnetic perturbations of edge-plasmas in toroidal confinement devices
    journal, November 2015


    Experimental signatures of homoclinic tangles in poloidally diverted tokamaks
    journal, January 2005


    Exploration of magnetic perturbation effects on advanced divertor configurations in NSTX-U
    dataset, January 2016

    • Frerichs, H.; Waters, I.; Schmitz, O.
    • Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
    • DOI: 10.11578/1562062