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Title: Edge Localized Mode Dynamics and Transport in the Scrape-Off Layer of the DIII-D Tokamak

Abstract

High temporal and spatial resolution measurements in the boundary of the DIII-D tokamak show that edge localized modes (ELMs) are produced in the low field side, are poloidally localized and are composed of fast bursts ({approx}20 to 40 {micro}s long) of hot, dense plasma on a background of less dense, colder plasma ({approx}5 x 10{sup 18} m{sup {+-}3}, 50 eV) possibly created by the bursts themselves. The ELMs travel radially in the scrapeoff layer (SOL), starting at the separatrix at {approx}450 m/s, and slow down to {approx}150 m/s near the wall, convecting particles and energy to the SOL and walls. The temperature and density in the ELM plasma initially correspond to those at the top of the density pedestal but quickly decay with radius in the SOL. The temperature decay length ({approx}1.2 to 1.5 cm) is much shorter than the density decay length ({approx}3 to 8 cm), and the latter decreases with increasing pedestal (and SOL) density. The local particle and energy flux at the midplane wall during the bursts are 10% to 50% ({approx}1 to 2 x 10{sup 21} m{sup {+-}2} s{sup {+-}1}) and 1% to 2 % ({approx}20 to 30 kW/m{sup 2}) respectively of the LCFS average fluxes,more » indicating that particles are transported radially much more efficiently than heat. Evidence is presented suggesting toroidal rotation of the ELM plasma in the SOL. The ELM plasma density and temperature increase linearly with discharge/pedestal density up to a Greenwald fraction of {approx}0.6, and then decrease resulting in more benign (grassier) ELMs.« less

Authors:
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Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
884786
Report Number(s):
UCRL-JRNL-208429
Journal ID: ISSN 1070-664X; PHPAEN; TRN: US0603686
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 12; Journal Issue: 7; Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; DECAY; DOUBLET-3 DEVICE; EDGE LOCALIZED MODES; PLASMA; PLASMA DENSITY; ROTATION; SOLS; SPATIAL RESOLUTION; TRANSPORT

Citation Formats

Boedo, J A, Rudakov, D L, Hollmann, E, Gray, D S, Burrell, K H, Moyer, R A, McKee, G R, Fonck, R, Stangeby, P C, Evans, T E, Snyder, P B, Leonard, A W, Mahdavi, M A, Schaffer, M J, West, W P, Fenstermacher, M E, Groth, M, Allen, S L, Porter, G D, Wolf, N S, Colchin, R J, Zeng, L, Wang, G, Watkins, J G, and Takahashi, T. Edge Localized Mode Dynamics and Transport in the Scrape-Off Layer of the DIII-D Tokamak. United States: N. p., 2004. Web.
Boedo, J A, Rudakov, D L, Hollmann, E, Gray, D S, Burrell, K H, Moyer, R A, McKee, G R, Fonck, R, Stangeby, P C, Evans, T E, Snyder, P B, Leonard, A W, Mahdavi, M A, Schaffer, M J, West, W P, Fenstermacher, M E, Groth, M, Allen, S L, Porter, G D, Wolf, N S, Colchin, R J, Zeng, L, Wang, G, Watkins, J G, & Takahashi, T. Edge Localized Mode Dynamics and Transport in the Scrape-Off Layer of the DIII-D Tokamak. United States.
Boedo, J A, Rudakov, D L, Hollmann, E, Gray, D S, Burrell, K H, Moyer, R A, McKee, G R, Fonck, R, Stangeby, P C, Evans, T E, Snyder, P B, Leonard, A W, Mahdavi, M A, Schaffer, M J, West, W P, Fenstermacher, M E, Groth, M, Allen, S L, Porter, G D, Wolf, N S, Colchin, R J, Zeng, L, Wang, G, Watkins, J G, and Takahashi, T. 2004. "Edge Localized Mode Dynamics and Transport in the Scrape-Off Layer of the DIII-D Tokamak". United States. https://www.osti.gov/servlets/purl/884786.
@article{osti_884786,
title = {Edge Localized Mode Dynamics and Transport in the Scrape-Off Layer of the DIII-D Tokamak},
author = {Boedo, J A and Rudakov, D L and Hollmann, E and Gray, D S and Burrell, K H and Moyer, R A and McKee, G R and Fonck, R and Stangeby, P C and Evans, T E and Snyder, P B and Leonard, A W and Mahdavi, M A and Schaffer, M J and West, W P and Fenstermacher, M E and Groth, M and Allen, S L and Porter, G D and Wolf, N S and Colchin, R J and Zeng, L and Wang, G and Watkins, J G and Takahashi, T},
abstractNote = {High temporal and spatial resolution measurements in the boundary of the DIII-D tokamak show that edge localized modes (ELMs) are produced in the low field side, are poloidally localized and are composed of fast bursts ({approx}20 to 40 {micro}s long) of hot, dense plasma on a background of less dense, colder plasma ({approx}5 x 10{sup 18} m{sup {+-}3}, 50 eV) possibly created by the bursts themselves. The ELMs travel radially in the scrapeoff layer (SOL), starting at the separatrix at {approx}450 m/s, and slow down to {approx}150 m/s near the wall, convecting particles and energy to the SOL and walls. The temperature and density in the ELM plasma initially correspond to those at the top of the density pedestal but quickly decay with radius in the SOL. The temperature decay length ({approx}1.2 to 1.5 cm) is much shorter than the density decay length ({approx}3 to 8 cm), and the latter decreases with increasing pedestal (and SOL) density. The local particle and energy flux at the midplane wall during the bursts are 10% to 50% ({approx}1 to 2 x 10{sup 21} m{sup {+-}2} s{sup {+-}1}) and 1% to 2 % ({approx}20 to 30 kW/m{sup 2}) respectively of the LCFS average fluxes, indicating that particles are transported radially much more efficiently than heat. Evidence is presented suggesting toroidal rotation of the ELM plasma in the SOL. The ELM plasma density and temperature increase linearly with discharge/pedestal density up to a Greenwald fraction of {approx}0.6, and then decrease resulting in more benign (grassier) ELMs.},
doi = {},
url = {https://www.osti.gov/biblio/884786}, journal = {Physics of Plasmas},
issn = {1070-664X},
number = 7,
volume = 12,
place = {United States},
year = {Fri Dec 03 00:00:00 EST 2004},
month = {Fri Dec 03 00:00:00 EST 2004}
}