skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Direct measurements of counter-streaming flows in a low-shear stellarator magnetic island topology

Abstract

We report on the first experimental verification of theoretically predicted multiple bundles of counter-streaming plasma flows in the island-divertor scrape-off layer (SOL) of the stellarator Wendelstein 7-X. In the standard toroidal field direction (counter-clockwise when looking from the top) experiments, the overall structure of the SOL flows, such as flow directions, the number of flow bundles and the magnitude of the flow velocities, are consistent with numerical predictions obtained with EMC3-EIRENE. However, the modelling does not predict changes of the flow patterns with reversal of the magnetic field direction, which are experimentally observed. This indicates that additional relevant physics, such as particle drifts, will need to be incorporated into the numerical model to better describe the whole stellarator scrape-off layer behaviour.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [1];  [1];  [1];  [1];  [3];  [4]; ORCiD logo [1]
  1. Max-Planck-Institut für Plasmaphysik, Greifswald (Germany)
  2. Univ. of Wisconsin, Madison, WI (United States); Princeton Univ., NJ (United States)
  3. Auburn Univ., Auburn, AL (United States)
  4. Univ. of Wisconsin, Madison, WI (United States)
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE
Contributing Org.:
the W7-X Team
OSTI Identifier:
1572710
Grant/Contract Number:  
SC0014529; SC0014210
Resource Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 59; Journal Issue: 12; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; island divertor; magnetic islands; scrape-off layer; impurity transport; plasma flows; coherence imaging spectroscopy

Citation Formats

Perseo, Valeria, Effenberg, F., Gradic, D., König, R., Ford, O. P., Reimold, F., Ennis, D. A., Schmitz, O., and Sunn Pedersen, T. Direct measurements of counter-streaming flows in a low-shear stellarator magnetic island topology. United States: N. p., 2019. Web. doi:10.1088/1741-4326/ab4320.
Perseo, Valeria, Effenberg, F., Gradic, D., König, R., Ford, O. P., Reimold, F., Ennis, D. A., Schmitz, O., & Sunn Pedersen, T. Direct measurements of counter-streaming flows in a low-shear stellarator magnetic island topology. United States. doi:10.1088/1741-4326/ab4320.
Perseo, Valeria, Effenberg, F., Gradic, D., König, R., Ford, O. P., Reimold, F., Ennis, D. A., Schmitz, O., and Sunn Pedersen, T. Thu . "Direct measurements of counter-streaming flows in a low-shear stellarator magnetic island topology". United States. doi:10.1088/1741-4326/ab4320. https://www.osti.gov/servlets/purl/1572710.
@article{osti_1572710,
title = {Direct measurements of counter-streaming flows in a low-shear stellarator magnetic island topology},
author = {Perseo, Valeria and Effenberg, F. and Gradic, D. and König, R. and Ford, O. P. and Reimold, F. and Ennis, D. A. and Schmitz, O. and Sunn Pedersen, T.},
abstractNote = {We report on the first experimental verification of theoretically predicted multiple bundles of counter-streaming plasma flows in the island-divertor scrape-off layer (SOL) of the stellarator Wendelstein 7-X. In the standard toroidal field direction (counter-clockwise when looking from the top) experiments, the overall structure of the SOL flows, such as flow directions, the number of flow bundles and the magnitude of the flow velocities, are consistent with numerical predictions obtained with EMC3-EIRENE. However, the modelling does not predict changes of the flow patterns with reversal of the magnetic field direction, which are experimentally observed. This indicates that additional relevant physics, such as particle drifts, will need to be incorporated into the numerical model to better describe the whole stellarator scrape-off layer behaviour.},
doi = {10.1088/1741-4326/ab4320},
journal = {Nuclear Fusion},
number = 12,
volume = 59,
place = {United States},
year = {2019},
month = {9}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Save / Share:

Works referenced in this record:

Drift effects in W7-AS limiter and island divertor configurations
journal, March 1999


Physics of island divertors as highlighted by the example of W7-AS
journal, July 2006


Transport-driven Scrape-Off-Layer flows and the boundary conditions imposed at the magnetic separatrix in a tokamak plasma
journal, September 2004


Absolute calibration of Doppler coherence imaging velocity images
journal, August 2017


Divertor operation in stellarators: results from W7-AS and implications for future devices
journal, September 2003


Divertor transport study in the large helical device
journal, June 2007


Divertor studies in nitrogen induced completely detached H-modes in full tungsten ASDEX Upgrade
journal, February 2015


Particle and power exhaust for a fusion plasma
journal, October 1990


HSX as an example of a resilient non-resonant divertor
journal, March 2017

  • Bader, A.; Boozer, A. H.; Hegna, C. C.
  • Physics of Plasmas, Vol. 24, Issue 3
  • DOI: 10.1063/1.4978494

Influence of magnetic field configurations on divertor plasma parameters in the W7-AS stellarator
journal, March 2003


Inter-ELM Power Decay Length for JET and ASDEX Upgrade: Measurement and Comparison with Heuristic Drift-Based Model
journal, November 2011


Coherence Imaging of Flows in the DIII-D Divertor
journal, March 2011

  • Howard, J.; Diallo, A.; Creese, M.
  • Contributions to Plasma Physics, Vol. 51, Issue 2-3
  • DOI: 10.1002/ctpp.201000062

Laser calibration of the DIII-D coherence imaging system
journal, October 2018

  • Allen, S. L.; Samuell, C. M.; Meyer, W. H.
  • Review of Scientific Instruments, Vol. 89, Issue 10
  • DOI: 10.1063/1.5038739

2D imaging of helium ion velocity in the DIII-D divertor
journal, May 2018

  • Samuell, C. M.; Porter, G. D.; Meyer, W. H.
  • Physics of Plasmas, Vol. 25, Issue 5
  • DOI: 10.1063/1.5017999

Doppler coherence imaging and tomography of flows in tokamak plasmas (invited)
journal, October 2010

  • Howard, J.; Diallo, A.; Creese, M.
  • Review of Scientific Instruments, Vol. 81, Issue 10
  • DOI: 10.1063/1.3492422

Comparative divertor-transport study for helical devices
journal, August 2009


Chapter 4: Power and particle control
journal, December 1999

  • Divertor, ITER Physics Expert Group on; Database, ITER Physics Expert Group on Divert; Editors, ITER Physics Basis
  • Nuclear Fusion, Vol. 39, Issue 12
  • DOI: 10.1088/0029-5515/39/12/304

Comparison between stellarator and tokamak divertor transport
journal, January 2011


Experimental divertor physics
journal, June 1997


Local island divertor experiments on LHD
journal, March 2005


Novel scanning interferometer for two‐dimensional plasma density measurements
journal, March 1990

  • Howard, John
  • Review of Scientific Instruments, Vol. 61, Issue 3
  • DOI: 10.1063/1.1141428

Time-resolved two-dimensional plasma spectroscopy using coherence-imaging techniques
journal, May 2003


Divertors for Helical Devices: Concepts, Plans, Results, and Problems
journal, July 2004

  • König, R.; Grigull, P.; McCormick, K.
  • Fusion Science and Technology, Vol. 46, Issue 1
  • DOI: 10.13182/FST04-A551

Neutral pressure behavior for diverted discharges in the Wendelstein 7-AS Stellarator
journal, March 2005


Numerical investigation of plasma edge transport and limiter heat fluxes in Wendelstein 7-X startup plasmas with EMC3-EIRENE
journal, January 2017


Tungsten as material for plasma-facing components in fusion devices
journal, August 2011


Coherence imaging spectro-polarimetry for magnetic fusion diagnostics
journal, July 2010


A new calibration implementation for Doppler Coherence Imaging Spectroscopy
journal, September 2019


Simulation of stellarator divertors
journal, September 2018

  • Boozer, Allen H.; Punjabi, Alkesh
  • Physics of Plasmas, Vol. 25, Issue 9
  • DOI: 10.1063/1.5042666

Fluid features of the stochastic layer transport in LHD
journal, January 2008


The divertor program in stellarators
journal, October 2002


Major results from the stellarator Wendelstein 7-AS
journal, March 2008


Modelling of island divertor physics and comparison to W7-AS experimental results
journal, March 2003


The effects of field reversal on the W7-AS island divertor at low densities
journal, March 1998


Verification of Doppler coherence imaging for 2D ion velocity measurements on DIII-D
journal, September 2018

  • Samuell, C. M.; Allen, S. L.; Meyer, W. H.
  • Review of Scientific Instruments, Vol. 89, Issue 9
  • DOI: 10.1063/1.5039367

Doppler coherence imaging of divertor and SOL flows in ASDEX upgrade and Wendelstein 7-X
journal, June 2018

  • Gradic, D.; Ford, O. P.; Burckhart, A.
  • Plasma Physics and Controlled Fusion, Vol. 60, Issue 8
  • DOI: 10.1088/1361-6587/aac4d2

Effective screening of iron impurities in the ergodic layer of the Large Helical Device with a metallic first wall
journal, August 2013


The EIRENE and B2-EIRENE Codes
journal, February 2005

  • Reiter, D.; Baelmans, M.; Börner, P.
  • Fusion Science and Technology, Vol. 47, Issue 2
  • DOI: 10.13182/FST47-172

2D distribution of hydrogen/impurity radiation and flow formation in stochastic layer during detachment transition in LHD
journal, August 2017


3D fluid modelling of the edge plasma by means of a Monte Carlo technique
journal, March 1999


Classical drifts in the tokamak SOL and divertor: models and experiment
journal, February 1997


Power exhaust by SOL and pedestal radiation at ASDEX Upgrade and JET
journal, August 2017


Three-dimensional scrape off layer transport in the helically symmetric experiment HSX
journal, June 2016


High Heat Flux Performance of Plasma Facing Materials and Components under Service Conditions in Future Fusion Reactors
journal, February 2006


Particle transport measurements in the LHD stochastic magnetic boundary plasma using Mach probes and ion sensitive probe
journal, August 2011


Transport in island divertors: physics, 3D modelling and comparison to first experiments on W7-AS*
journal, May 2002


Coherence imaging of scrape-off-layer and divertor impurity flows in the Mega Amp Spherical Tokamak (invited)
journal, November 2014

  • Silburn, S. A.; Harrison, J. R.; Howard, J.
  • Review of Scientific Instruments, Vol. 85, Issue 11
  • DOI: 10.1063/1.4891165

Synthetic plasma edge diagnostics for EMC3-EIRENE, highlighted for Wendelstein 7-X
journal, September 2016

  • Frerichs, H.; Effenberg, F.; Schmitz, O.
  • Review of Scientific Instruments, Vol. 87, Issue 11
  • DOI: 10.1063/1.4959910

Armour Materials for the ITER Plasma Facing Components
journal, January 1999


Two-dimensional study of edge impurity transport in the Large Helical Device
journal, August 2014


Experimental Investigation of the Magnetic Configuration Dependence of Turbulent Transport
journal, July 2011


Physical Aspects and Design of the Wendelstein 7-X Divertor
journal, September 2004

  • Renner, Hermann; Sharma, Devendra; Kißlinger, Johann
  • Fusion Science and Technology, Vol. 46, Issue 2
  • DOI: 10.13182/FST04-A570

The effect of divertor magnetic balance on H-mode performance in DIII-D
journal, March 2001


Investigation of 3D effects on heat fluxes in performance-optimized island divertor configurations at Wendelstein 7-X
journal, January 2019


Sustained Stabilization of the Resistive-Wall Mode by Plasma Rotation in the DIII-D Tokamak
journal, November 2002