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

Abstract

High resolution plasma transport simulations with the EMC3-EIRENE code have been performed to address the parallel plasma flow structure in the boundary of a poloidal divertor configuration with non-axisymmetric perturbations at DIII-D. Simulation results show that a checkerboard pattern of flows with alternating direction is generated inside the separatrix. This pattern is aligned with the position of the main resonances (i.e. where the safety factor is equal to rational values q = m/n for a perturbation field with base mode number n): m pairs of alternating forward and backward flow channel exist for each resonance. The poloidal oscillations are aligned with the subharmonic Melnikov function, which indicates that the plasma flow is generated by parallel pressure gradients along perturbed field lines. Lastly, an additional scrape-off layer-like domain is introduced by the perturbed separatrix which guides field lines from the interior to the divertor targets, resulting in an enhanced outward flow that is consistent with the experimentally observed particle pump-out effect. However, while the lobe structure of the perturbed separatrix is very well reflected in the temperature profile, the same lobes can appear to be smaller in the flow profile due to a competition between high upstream pressure and downstream particlemore » sources driving flows in opposite directions.« less

Authors:
 [1];  [1]; ORCiD logo [2];  [3];  [4]
  1. Univ. of Wisconsin, Madison, WI (United States). Dept. of Engineering Physics
  2. General Atomics, San Diego, CA (United States)
  3. Max-Planck Inst. for Plasma Physics, Greifswald (Germany)
  4. Forschungszentrum Julich (Germany). Inst. for Energy and Climate Research (IEK) - Plasma Physics
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1375953
Alternate Identifier(s):
OSTI ID: 1228665
Grant/Contract Number:  
FC02-04ER54698; SC0013911
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 22; Journal Issue: 7; 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

Citation Formats

Frerichs, H., Schmitz, Oliver, Evans, Todd, Feng, Y., and Reiter, D. The pattern of parallel edge plasma flows due to pressure gradients, recycling, and resonant magnetic perturbations in DIII-D. United States: N. p., 2015. Web. doi:10.1063/1.4926524.
Frerichs, H., Schmitz, Oliver, Evans, Todd, Feng, Y., & Reiter, D. The pattern of parallel edge plasma flows due to pressure gradients, recycling, and resonant magnetic perturbations in DIII-D. United States. https://doi.org/10.1063/1.4926524
Frerichs, H., Schmitz, Oliver, Evans, Todd, Feng, Y., and Reiter, D. 2015. "The pattern of parallel edge plasma flows due to pressure gradients, recycling, and resonant magnetic perturbations in DIII-D". United States. https://doi.org/10.1063/1.4926524. https://www.osti.gov/servlets/purl/1375953.
@article{osti_1375953,
title = {The pattern of parallel edge plasma flows due to pressure gradients, recycling, and resonant magnetic perturbations in DIII-D},
author = {Frerichs, H. and Schmitz, Oliver and Evans, Todd and Feng, Y. and Reiter, D.},
abstractNote = {High resolution plasma transport simulations with the EMC3-EIRENE code have been performed to address the parallel plasma flow structure in the boundary of a poloidal divertor configuration with non-axisymmetric perturbations at DIII-D. Simulation results show that a checkerboard pattern of flows with alternating direction is generated inside the separatrix. This pattern is aligned with the position of the main resonances (i.e. where the safety factor is equal to rational values q = m/n for a perturbation field with base mode number n): m pairs of alternating forward and backward flow channel exist for each resonance. The poloidal oscillations are aligned with the subharmonic Melnikov function, which indicates that the plasma flow is generated by parallel pressure gradients along perturbed field lines. Lastly, an additional scrape-off layer-like domain is introduced by the perturbed separatrix which guides field lines from the interior to the divertor targets, resulting in an enhanced outward flow that is consistent with the experimentally observed particle pump-out effect. However, while the lobe structure of the perturbed separatrix is very well reflected in the temperature profile, the same lobes can appear to be smaller in the flow profile due to a competition between high upstream pressure and downstream particle sources driving flows in opposite directions.},
doi = {10.1063/1.4926524},
url = {https://www.osti.gov/biblio/1375953}, journal = {Physics of Plasmas},
issn = {1070-664X},
number = 7,
volume = 22,
place = {United States},
year = {Mon Jul 13 00:00:00 EDT 2015},
month = {Mon Jul 13 00:00:00 EDT 2015}
}

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Cited by: 19 works
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Works referenced in this record:

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


Measurement and modeling of three-dimensional equilibria in DIII-D
journal, May 2011


Experimental imaging of separatrix splitting on DIII-D
journal, November 2012


Screening of resonant magnetic perturbations by flows in tokamaks
journal, May 2012


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Calculation of stochastic thermal transport due to resonant magnetic perturbations in DIII-D
journal, March 2008


High resolution numerical studies of separatrix splitting due to non-axisymmetric perturbation in DIII-D
journal, April 2009


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journal, November 2008


STELLOPT modeling of the 3D diagnostic response in ITER
journal, June 2013


ELM mitigation techniques
journal, July 2013


Striation pattern of target particle and heat fluxes in three dimensional simulations for DIII-D
journal, February 2014


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


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journal, January 2005


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journal, September 2003


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Importance of plasma response to nonaxisymmetric perturbations in tokamaks
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Works referencing / citing this record:

Exploration of magnetic perturbation effects on advanced divertor configurations in NSTX-U
journal, June 2016


3D effects of neon injection positions on the toroidally symmetric/asymmetric heat flux distribution on EAST
journal, January 2020


Field aligned flows driven by neutral puffing at MAST
journal, April 2018