Effect of scrape-off-layer current on reconstructed tokamak equilibrium

King, J. R.; Kruger, S. E.; Groebner, R. J.; Hanson, J. D.; Hebert, J. D.; Held, E. D.; Jepson, J. R.

doi:10.1063/1.4972822

Title: Effect of scrape-off-layer current on reconstructed tokamak equilibrium

Abstract

Methods are described that extend fields from reconstructed equilibria to include scrape-off-layer current through extrapolated parametrized and experimental fits. The extrapolation includes both the effects of the toroidal-field and pressure gradients which produce scrape-off-layer current after recomputation of the Grad-Shafranov solution. To quantify the degree that inclusion of scrape-off-layer current modifies the equilibrium, the χ-squared goodness-of-fit parameter is calculated for cases with and without scrape-off-layer current. The change in χ-squared is found to be minor when scrape-off-layer current is included however flux surfaces are shifted by up to 3 cm. Here the impact on edge modes of these scrape-off-layer modifications is also found to be small and the importance of these methods to nonlinear computation is discussed.

Authors:

^[1];

^[1]; Groebner, R. J. ^[2]; Hanson, J. D. ^[3]; Hebert, J. D. ^[3]; Held, E. D. ^[4];

^[4]

Tech-X Corp., Boulder, CO (United States)
General Atomics, San Diego, CA (United States)
Auburn Univ., Auburn, AL (United States)
Utah State Univ., Logan, UT (United States)

Publication Date:: Fri Jan 13 00:00:00 EST 2017

Research Org.:: Tech-X Corp., Boulder, CO (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Fusion Energy Sciences (FES)

Contributing Org.:: General Atomics, San Diego, CA; Auburn University, Auburn, AL; Utah State University, Logan, UT

OSTI Identifier:: 1339429

Alternate Identifier(s):: OSTI ID: 1361709

Grant/Contract Number:: FC02-08ER54972; AC02-05CH11231; FC02-04ER54698; FC02-06ER54875; FG02-03ER54692

Resource Type:: Accepted Manuscript

Journal Name:: Physics of Plasmas

Additional Journal Information:: Journal Volume: 24; Journal Issue: 1; 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; Grad-Shafranov equilibrium; scrape-off-layer; macroscopic stability; peeling-balooning modes

Citation Formats


                    King, J. R., Kruger, S. E., Groebner, R. J., Hanson, J. D., Hebert, J. D., Held, E. D., and Jepson, J. R. Effect of scrape-off-layer current on reconstructed tokamak equilibrium.  United States: N. p., 2017. 
Web.  doi:10.1063/1.4972822.

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                    King, J. R., Kruger, S. E., Groebner, R. J., Hanson, J. D., Hebert, J. D., Held, E. D., & Jepson, J. R. Effect of scrape-off-layer current on reconstructed tokamak equilibrium.  United States.  https://doi.org/10.1063/1.4972822

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                    King, J. R., Kruger, S. E., Groebner, R. J., Hanson, J. D., Hebert, J. D., Held, E. D., and Jepson, J. R. Fri .  
"Effect of scrape-off-layer current on reconstructed tokamak equilibrium".  United States.  https://doi.org/10.1063/1.4972822.  https://www.osti.gov/servlets/purl/1339429.

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@article{osti_1339429,

  title        = {Effect of scrape-off-layer current on reconstructed tokamak equilibrium},

  author       = {King, J. R. and Kruger, S. E. and Groebner, R. J. and Hanson, J. D. and Hebert, J. D. and Held, E. D. and Jepson, J. R.},

  abstractNote = {Methods are described that extend fields from reconstructed equilibria to include scrape-off-layer current through extrapolated parametrized and experimental fits. The extrapolation includes both the effects of the toroidal-field and pressure gradients which produce scrape-off-layer current after recomputation of the Grad-Shafranov solution. To quantify the degree that inclusion of scrape-off-layer current modifies the equilibrium, the χ-squared goodness-of-fit parameter is calculated for cases with and without scrape-off-layer current. The change in χ-squared is found to be minor when scrape-off-layer current is included however flux surfaces are shifted by up to 3 cm. Here the impact on edge modes of these scrape-off-layer modifications is also found to be small and the importance of these methods to nonlinear computation is discussed.},

  doi          = {10.1063/1.4972822},

  journal      = {Physics of Plasmas},

  number       = 1,

  volume       = 24,

  place        = {United States},

  year         = {Fri Jan 13 00:00:00 EST 2017},

  month        = {Fri Jan 13 00:00:00 EST 2017}

}

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Title: Effect of scrape-off-layer current on reconstructed tokamak equilibrium

Abstract

Citation Formats

Ideal and resistive edge stability calculations with M3D-C1 journal, October 2010

Simultaneous measurement of q and Er profiles using the motional Stark effect in high-performance DIII-D plasmas (invited) journal, January 1999

Dynamics of the major disruption of a DIII-D plasma journal, May 2005

Scrape-off layer transport and deposition studies in DIII-D journal, May 2007

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

Equilibrium analysis of current profiles in tokamaks journal, June 1990

Nonlinear magnetohydrodynamics simulation using high-order finite elements journal, March 2004

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First-order finite-Larmor-radius effects on magnetic tearing in pinch configurations journal, April 2011

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Erratum: “New regime of low ion collisionality in the neoclassical equilibrium of tokamak plasmas” [Phys. Plasmas 22, 070702 (2015)] journal, November 2015

Verification of continuum drift kinetic equation solvers in NIMROD journal, March 2015

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Spatial calibration of a tokamak neutral beam diagnostic using in situ neutral beam emission journal, October 2015

Beta limits in long-pulse tokamak discharges journal, May 1997

A high-order implicit finite element method for integrating the two-fluid magnetohydrodynamic equations in two dimensions journal, October 2007

Spectroscopic study of edge poloidal rotation and radial electric fields in the DIII‐D tokamak (invited) journal, October 1990

A parametric study of the drift-tearing mode using an extended-magnetohydrodynamic model journal, October 2014

Determination of the parameters I and l i in a Tokamak for arbitrary shape of plasma pinch cross-section journal, September 1971

The CHEASE code for toroidal MHD equilibria journal, September 1996

Calculating electron cyclotron current drive stabilization of resistive tearing modes in a nonlinear magnetohydrodynamic model journal, January 2010

GATO: An MHD stability code for axisymmetric plasmas with internal separatrices journal, December 1981

Edge localized modes and the pedestal: A model based on coupled peeling–ballooning modes journal, May 2002

Observation of poloidal current flow to the vacuum vessel wall during vertical instabilities in the DIII-D tokamak journal, March 1991

Scaling of the tokamak near the scrape-off layer H-mode power width and implications for ITER journal, August 2013

Solving the Grad–Shafranov equation with spectral elements journal, May 2014

The impact of collisionality, FLR, and parallel closure effects on instabilities in the tokamak pedestal: Numerical studies with the NIMROD code journal, June 2016

Design and operation of the multipulse Thomson scattering diagnostic on DIII‐D (invited) journal, October 1992

NIMROD modeling of quiescent H-mode: reconstruction considerations and saturation mechanism journal, September 2016

Measurements of core electron temperature and density fluctuations in DIII-D and comparison to nonlinear gyrokinetic simulations journal, May 2008

Calculations of two-fluid magnetohydrodynamic axisymmetric steady-states journal, November 2009

Motional Stark effect polarimetry for a current profile diagnostic in DIII‐D journal, November 1990

MHD simulations with resistive wall and magnetic separatrix journal, December 2004

Magnetohydrodynamic equilibria of attached plasmas after loss of vertical stability in elongated tokamaks journal, October 1991

Computational modeling of fully ionized magnetized plasmas using the fluid approximation journal, May 2006

Noncircular, finite aspect ratio, local equilibrium model journal, April 1998

Edge localized linear ideal magnetohydrodynamic instability studies in an extended-magnetohydrodynamic code journal, March 2010

Analysis of a mixed semi-implicit/implicit algorithm for low-frequency two-fluid plasma modeling journal, August 2010

New regime of low ion collisionality in the neoclassical equilibrium of tokamak plasmas journal, July 2015

Ideal and resistive edge stability calculations with M3D-C1
journal, October 2010

Simultaneous measurement of q and Er profiles using the motional Stark effect in high-performance DIII-D plasmas (invited)
journal, January 1999

Dynamics of the major disruption of a DIII-D plasma
journal, May 2005

Scrape-off layer transport and deposition studies in DIII-D
journal, May 2007

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

Equilibrium analysis of current profiles in tokamaks
journal, June 1990

Nonlinear magnetohydrodynamics simulation using high-order finite elements
journal, March 2004

Numerical Method for the Stability Analysis of Ideal MHD Modes with a Wide Range of Toroidal Mode Numbers in Tokamaks
journal, January 2007

First-order finite-Larmor-radius effects on magnetic tearing in pinch configurations
journal, April 2011

Initial results of the high resolution edge Thomson scattering upgrade at DIII-D
journal, October 2012

Erratum: “New regime of low ion collisionality in the neoclassical equilibrium of tokamak plasmas” [Phys. Plasmas 22, 070702 (2015)]
journal, November 2015

Verification of continuum drift kinetic equation solvers in NIMROD
journal, March 2015

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

Spatial calibration of a tokamak neutral beam diagnostic using in situ neutral beam emission
journal, October 2015

Beta limits in long-pulse tokamak discharges
journal, May 1997

A high-order implicit finite element method for integrating the two-fluid magnetohydrodynamic equations in two dimensions
journal, October 2007

Spectroscopic study of edge poloidal rotation and radial electric fields in the DIII‐D tokamak (invited)
journal, October 1990

A parametric study of the drift-tearing mode using an extended-magnetohydrodynamic model
journal, October 2014

Determination of the parameters _I and l _i in a Tokamak for arbitrary shape of plasma pinch cross-section
journal, September 1971

The CHEASE code for toroidal MHD equilibria
journal, September 1996

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journal, January 2010

GATO: An MHD stability code for axisymmetric plasmas with internal separatrices
journal, December 1981

Edge localized modes and the pedestal: A model based on coupled peeling–ballooning modes
journal, May 2002

Observation of poloidal current flow to the vacuum vessel wall during vertical instabilities in the DIII-D tokamak
journal, March 1991

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journal, August 2013

Solving the Grad–Shafranov equation with spectral elements
journal, May 2014

The impact of collisionality, FLR, and parallel closure effects on instabilities in the tokamak pedestal: Numerical studies with the NIMROD code
journal, June 2016

Design and operation of the multipulse Thomson scattering diagnostic on DIII‐D (invited)
journal, October 1992

NIMROD modeling of quiescent H-mode: reconstruction considerations and saturation mechanism
journal, September 2016

Measurements of core electron temperature and density fluctuations in DIII-D and comparison to nonlinear gyrokinetic simulations
journal, May 2008

Calculations of two-fluid magnetohydrodynamic axisymmetric steady-states
journal, November 2009

Motional Stark effect polarimetry for a current profile diagnostic in DIII‐D
journal, November 1990

MHD simulations with resistive wall and magnetic separatrix
journal, December 2004

Magnetohydrodynamic equilibria of attached plasmas after loss of vertical stability in elongated tokamaks
journal, October 1991

Computational modeling of fully ionized magnetized plasmas using the fluid approximation
journal, May 2006

Noncircular, finite aspect ratio, local equilibrium model
journal, April 1998

Edge localized linear ideal magnetohydrodynamic instability studies in an extended-magnetohydrodynamic code
journal, March 2010

Analysis of a mixed semi-implicit/implicit algorithm for low-frequency two-fluid plasma modeling
journal, August 2010

New regime of low ion collisionality in the neoclassical equilibrium of tokamak plasmas
journal, July 2015