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Title: Pedestal-to-Wall 3D Fluid Transport Simulations on DIII-D

Abstract

The 3D fluid-plasma edge transport code EMC3-EIRENE is used to test several magnetic field models with and without plasma response against DIII-D experimental data for even and odd-parity n=3 magnetic field perturbations. The field models include ideal and extended MHD equilibria, and the vacuum approximation. Plasma response is required to reduce the stochasticity in the pedestal region for even-parity fields, however too much screening suppresses the measured splitting of the downstream T e profile. Odd-parity perturbations result in weak tearing and only small additional peaks in the downstream measurements. In this case plasma response is required to increase the size of the lobe structure. Finally, no single model is able to simultaneously reproduce the upstream and downstream characteristics for both odd and even-parity perturbations.

Authors:
 [1];  [1];  [2];  [3];  [4];  [5];  [2];  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  3. Univ. of Wisconsin, Madison, WI (United States)
  4. Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States); General Atomics, San Diego, CA (United States)
  5. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); General Atomics, San Diego, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1364303
Alternate Identifier(s):
OSTI ID: 1374591
Grant/Contract Number:
AC05-00OR22725; FC02-04ER54698; AC02-09CH11466; AC52-07NA27344
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 57; Journal Issue: 5; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 3D transport; plasma response; boundary modeling

Citation Formats

Lore, Jeremy D., Wolfmeister, Alexis Briesemeister, Ferraro, Nathaniel M., Frerichs, Heinke, Lyons, B., McLean, A., Park, J.-K, and Shafer, Morgan W. Pedestal-to-Wall 3D Fluid Transport Simulations on DIII-D. United States: N. p., 2017. Web. doi:10.1088/1741-4326/aa64ad.
Lore, Jeremy D., Wolfmeister, Alexis Briesemeister, Ferraro, Nathaniel M., Frerichs, Heinke, Lyons, B., McLean, A., Park, J.-K, & Shafer, Morgan W. Pedestal-to-Wall 3D Fluid Transport Simulations on DIII-D. United States. doi:10.1088/1741-4326/aa64ad.
Lore, Jeremy D., Wolfmeister, Alexis Briesemeister, Ferraro, Nathaniel M., Frerichs, Heinke, Lyons, B., McLean, A., Park, J.-K, and Shafer, Morgan W. Thu . "Pedestal-to-Wall 3D Fluid Transport Simulations on DIII-D". United States. doi:10.1088/1741-4326/aa64ad. https://www.osti.gov/servlets/purl/1364303.
@article{osti_1364303,
title = {Pedestal-to-Wall 3D Fluid Transport Simulations on DIII-D},
author = {Lore, Jeremy D. and Wolfmeister, Alexis Briesemeister and Ferraro, Nathaniel M. and Frerichs, Heinke and Lyons, B. and McLean, A. and Park, J.-K and Shafer, Morgan W.},
abstractNote = {The 3D fluid-plasma edge transport code EMC3-EIRENE is used to test several magnetic field models with and without plasma response against DIII-D experimental data for even and odd-parity n=3 magnetic field perturbations. The field models include ideal and extended MHD equilibria, and the vacuum approximation. Plasma response is required to reduce the stochasticity in the pedestal region for even-parity fields, however too much screening suppresses the measured splitting of the downstream Te profile. Odd-parity perturbations result in weak tearing and only small additional peaks in the downstream measurements. In this case plasma response is required to increase the size of the lobe structure. Finally, no single model is able to simultaneously reproduce the upstream and downstream characteristics for both odd and even-parity perturbations.},
doi = {10.1088/1741-4326/aa64ad},
journal = {Nuclear Fusion},
number = 5,
volume = 57,
place = {United States},
year = {Thu Mar 30 00:00:00 EDT 2017},
month = {Thu Mar 30 00:00:00 EDT 2017}
}

Journal Article:
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  • The 3D fluid-plasma edge transport code EMC3-EIRENE is used to test several magnetic field models with and without plasma response against DIII-D experimental data for even and odd-parity n=3 magnetic field perturbations. The field models include ideal and extended MHD equilibria, and the vacuum approximation. Plasma response is required to reduce the stochasticity in the pedestal region for even-parity fields, however too much screening suppresses the measured splitting of the downstream Te profile. Odd-parity perturbations result in weak tearing and only small additional peaks in the downstream measurements. In this case plasma response is required to increase the size ofmore » the lobe structure. No single model is able to simultaneously reproduce the upstream and downstream characteristics for both odd and even-parity perturbations.« less
  • A new procedure for inferring {chi}{sub i,e}{sup exp} in the plasma edge from experimental data and integrated modeling code calculations has been developed that takes into account atomic physics and radiation effects and convective as well as conductive heat flux profiles. Application to DIII-D [J. Luxon, Nucl. Fusion 42, 614 (2002)] shots indicates that proper inference of {chi}{sub i,e}{sup exp} in the edge pedestal (sharp gradient region) depends on accounting for the variation in electron and ion heat fluxes and in the convective fraction of each over the edge region. The frequently observed steep edge temperature gradients are found tomore » depend as much on the variation in conductive and convective heat fluxes as on a reduction in {chi}{sub i,e}. Inferred {chi}{sub i,e}{sup exp} are compared with theoretical predictions.« less
  • The evolution of diffusive and non-diffusive transport during pedestal buildup following a low-high (L-H) transition has been interpreted from a particle-momentum-energy balance analysis of the measured density, temperature, and rotation velocity profiles in the plasma edge (0.82<{rho}<1.0) of a DIII-D [Luxon, Nucl. Fusion 42, 614 (2002)] discharge. In the discharge examined, there was an edge-localized-mode-free period of more than 600 ms following the L-H transition, and the majority of edge pedestal development occurred within the first 100 ms following the L-H transition. There appears to be a spatio-temporal correlation among the measured toroidal and poloidal rotation, the formation of amore » negative well in the measured radial electric field, the creation of a large inward particle pinch, the calculated intrinsic rotation due to ion orbit loss, and the measured formation of steep gradients in density and temperature in the outer region ({rho}>0.95) of the edge pedestal.« less
  • Evolution of measured profiles of densities, temperatures, and velocities in the edge pedestal region between successive ELM (edge-localized mode) events are analyzed and interpreted in terms of the constraints imposed by particle, momentum and energy balance in order to gain insights regarding the underlying evolution of transport processes in the edge pedestal between ELMs in a series of DIII-D [J. Luxon, Nucl. Fusion 42, 614 (2002)] discharges. The data from successive inter-ELM periods during an otherwise steady-state phase of the discharges were combined into a composite inter-ELM period for the purpose of increasing the number of data points in themore » analysis. Variation of diffusive and non-diffusive (pinch) particle, momentum, and energy transport over the inter-ELM period are interpreted using the GTEDGE code for discharges with plasma currents from 0.5 to 1.5 MA and inter-ELM periods from 50 to 220 ms. Diffusive transport is dominant for ρ < 0.925, while non-diffusive and diffusive transport are very large and nearly balancing in the sharp gradient region 0.925 < ρ < 1.0. During the inter-ELM period, diffusive transport increases slightly more than non-diffusive transport, increasing total outward transport. Both diffusive and non-diffusive transport have a strong inverse correlation with plasma current.« less