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

Title: Effects of two-dimensional magnetic uncertainties and three-dimensional error and perturbation fields on the Small Angle Slot divertor geometry and topology [Effects of two- and three-dimensional magnetic fields on the Small Angle Slot divertor magnetic topology]

Abstract

The Small Angle Slot (SAS) was recently installed on DIII-D as an advanced divertor, promising easier plasma detachment and lower temperatures across the whole target. A twofold study of the SAS magnetic geometry and topology is presented in this paper. On one hand, a two-dimensional uncertainty quantification analysis is carried out through a Monte Carlo approach in order to understand the level of accuracy of two-dimensional equilibrium computations in reconstructing the strike point and angle onto the divertor. Under typical experimental conditions, the uncertainties are found to be roughly 6.8 mm and 0.56 deg, respectively. On the other hand, a three-dimensional 'vacuum' analysis is carried out to understand the effects of typical external perturbation fields on the scrape-off layer topology. When the non-axisymmetric I-coils are switched on, poloidally-localized lobes are found to appear, grow, and hit the SAS target, although barely, even for 5 kA; at the same time, the strike point modulation is found to be roughly 1.8 mm and thus negligible for most purposes. Such results complement previous two-dimensional analyses in characterizing typical SAS equilibria and provide useful background information for planning and interpreting SAS experiments.

Authors:
ORCiD logo [1];  [2];  [2];  [2];  [3];  [2];  [4];  [2]
  1. Oak Ridge Associated Univ., Oak Ridge, TN (United States); General Atomics, San Diego, CA (United States)
  2. General Atomics, San Diego, CA (United States)
  3. Univ. of California-San Diego, San Diego, CA (United States)
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Nuclear Energy (NE)
OSTI Identifier:
1415991
Alternate Identifier(s):
OSTI ID: 1422607
Grant/Contract Number:  
FC02-04ER54698; AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 58; Journal Issue: 2; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; plasma physics; DIII-D; magnetic topology; divertor footprint

Citation Formats

Trevisan, Gregorio L., Lao, Lang L., Evans, Todd E., Guo, Hou Yang, Orlov, Dmitry M., Strait, Edward J., Wingen, Andreas, and Wu, Wen. Effects of two-dimensional magnetic uncertainties and three-dimensional error and perturbation fields on the Small Angle Slot divertor geometry and topology [Effects of two- and three-dimensional magnetic fields on the Small Angle Slot divertor magnetic topology]. United States: N. p., 2018. Web. https://doi.org/10.1088/1741-4326/aa9dab.
Trevisan, Gregorio L., Lao, Lang L., Evans, Todd E., Guo, Hou Yang, Orlov, Dmitry M., Strait, Edward J., Wingen, Andreas, & Wu, Wen. Effects of two-dimensional magnetic uncertainties and three-dimensional error and perturbation fields on the Small Angle Slot divertor geometry and topology [Effects of two- and three-dimensional magnetic fields on the Small Angle Slot divertor magnetic topology]. United States. https://doi.org/10.1088/1741-4326/aa9dab
Trevisan, Gregorio L., Lao, Lang L., Evans, Todd E., Guo, Hou Yang, Orlov, Dmitry M., Strait, Edward J., Wingen, Andreas, and Wu, Wen. Thu . "Effects of two-dimensional magnetic uncertainties and three-dimensional error and perturbation fields on the Small Angle Slot divertor geometry and topology [Effects of two- and three-dimensional magnetic fields on the Small Angle Slot divertor magnetic topology]". United States. https://doi.org/10.1088/1741-4326/aa9dab. https://www.osti.gov/servlets/purl/1415991.
@article{osti_1415991,
title = {Effects of two-dimensional magnetic uncertainties and three-dimensional error and perturbation fields on the Small Angle Slot divertor geometry and topology [Effects of two- and three-dimensional magnetic fields on the Small Angle Slot divertor magnetic topology]},
author = {Trevisan, Gregorio L. and Lao, Lang L. and Evans, Todd E. and Guo, Hou Yang and Orlov, Dmitry M. and Strait, Edward J. and Wingen, Andreas and Wu, Wen},
abstractNote = {The Small Angle Slot (SAS) was recently installed on DIII-D as an advanced divertor, promising easier plasma detachment and lower temperatures across the whole target. A twofold study of the SAS magnetic geometry and topology is presented in this paper. On one hand, a two-dimensional uncertainty quantification analysis is carried out through a Monte Carlo approach in order to understand the level of accuracy of two-dimensional equilibrium computations in reconstructing the strike point and angle onto the divertor. Under typical experimental conditions, the uncertainties are found to be roughly 6.8 mm and 0.56 deg, respectively. On the other hand, a three-dimensional 'vacuum' analysis is carried out to understand the effects of typical external perturbation fields on the scrape-off layer topology. When the non-axisymmetric I-coils are switched on, poloidally-localized lobes are found to appear, grow, and hit the SAS target, although barely, even for 5 kA; at the same time, the strike point modulation is found to be roughly 1.8 mm and thus negligible for most purposes. Such results complement previous two-dimensional analyses in characterizing typical SAS equilibria and provide useful background information for planning and interpreting SAS experiments.},
doi = {10.1088/1741-4326/aa9dab},
journal = {Nuclear Fusion},
number = 2,
volume = 58,
place = {United States},
year = {2018},
month = {1}
}

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

Save / Share:

Works referenced in this record:

Error field mode studies on JET, COMPASS-D and DIII-D, and implications for ITER
journal, November 1999


Modeling of stochastic magnetic flux loss from the edge of a poloidally diverted tokamak
journal, December 2002

  • Evans, T. E.; Moyer, R. A.; Monat, P.
  • Physics of Plasmas, Vol. 9, Issue 12
  • DOI: 10.1063/1.1521125

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

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


Experimental and numerical studies of separatrix splitting and magnetic footprints in DIII-D
journal, June 2007


Real time equilibrium reconstruction for tokamak discharge control
journal, July 1998


MAST-upgrade divertor facility and assessing performance of long-legged divertors
journal, July 2013


Accelerating the numerical simulation of magnetic field lines in tokamaks using the GPU
journal, June 2011


Separation of β̄ p and ℓ i in tokamaks of non-circular cross-section
journal, October 1985


Reconstruction of current profile parameters and plasma shapes in tokamaks
journal, November 1985


Proposal of an alternative upper divertor in ASDEX Upgrade supported by EMC3-EIRENE simulations
journal, August 2017


A design retrospective of the DIII-D tokamak
journal, May 2002


Anomalies in the applied magnetic fields in DIII-D and their implications for the understanding of stability experiments
journal, December 2003


Integrated modeling applications for tokamak experiments with OMFIT
journal, July 2015


Dynamic diagnostics of the error fields in tokamaks
journal, June 2007


TCV divertor upgrade for alternative magnetic configurations
journal, August 2017


Measurement of resistive wall mode stability in rotating high-β DIII-D plasmas
journal, April 2005


Advances in global MHD mode stabilization research on NSTX
journal, January 2010


Strong correlation between D 2 density and electron temperature at the target of divertors found in SOLPS analysis
journal, March 2017


Magnetic diagnostic system of the DIII-D tokamak
journal, February 2006

  • Strait, E. J.
  • Review of Scientific Instruments, Vol. 77, Issue 2
  • DOI: 10.1063/1.2166493

Footprint structures due to resonant magnetic perturbations in DIII-D
journal, April 2009

  • Wingen, A.; Evans, T. E.; Spatschek, K. H.
  • Physics of Plasmas, Vol. 16, Issue 4
  • DOI: 10.1063/1.3099053

Nonaxisymmetric field effects on Alcator C-Mod
journal, May 2005

  • Wolfe, S. M.; Hutchinson, I. H.; Granetz, R. S.
  • Physics of Plasmas, Vol. 12, Issue 5
  • DOI: 10.1063/1.1883665

    Works referencing / citing this record:

    Assessment of equilibrium field coil misalignments on the divertor footprints in NSTX-U
    journal, June 2019