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Title: Radiative and SOL experiments in open and baffled divertors on DIII-D

Abstract

The authors present recent progress towards an understanding of the physical processes in the divertor and scrape-off-layer (SOL) plasmas in DIII-D. This has been made possible by a combination of new diagnostics, improved computational models, and changes in divertor geometry. They have focused primarily on ELMing H-mode discharges. The physics of Partially Detached Divertor (PDD) plasmas, with divertor heat flux reduction by divertor radiation enhancement using D{sub 2} puffing, has been studied in 2-D, and a model of the heat and particle transport has been developed that includes conduction, convection, ionization, recombination, and flows. Plasma and impurity particle flows have been measured with Mach probes and spectroscopy and these flows have been compared with the UEDGE model. The model now includes self-consistent calculations of carbon impurities. Impurity radiation has been increased in the divertor and SOL with puff and pump techniques using SOL D{sub 2} puffing, divertor cryopumping, and argon puffing. The important physical processes in plasma-wall interactions have been examined with a DiMES probe, plasma characterization near the divertor plate, and the REDEP code. Experiments comparing single-null (SN) plasma operation in baffled and open divertors have demonstrated a change in the edge plasma profiles. These results are consistent withmore » a reduction in the core ionization source calculated with UEDGE. Divertor particle control in ELMing H-mode with pumping and baffling has resulted in reduction in H-mode core densities to n{sub e}/n{sub gw} {approx} 0.25. Divertor particle exhaust and heat flux has been studied as the plasma shape was varied from a lower SN, to a balanced double null (DN), and finally to an upper SN.« less

Authors:
 [1];  [2];  [3]
  1. Lawrence Livermore National Lab., CA (United States)
  2. General Atomics, San Diego, CA (United States)
  3. Sandia National Lab., Livermore, CA (United States); and others
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States); Lawrence Livermore National Lab., CA (United States); Oak Ridge National Lab., TN (United States); Sandia National Lab., Livermore, CA (United States)
Sponsoring Org.:
USDOE Office of Energy Research, Washington, DC (United States)
OSTI Identifier:
296835
Report Number(s):
GA-A23004; CONF-981064-
ON: DE99001350; TRN: 99:002476
DOE Contract Number:  
AC03-89ER51114; W-7405-ENG-48; AC05-96OR22464; AC04-94AL85000; FG03-92ER54150
Resource Type:
Conference
Resource Relation:
Conference: 17. IAEA fusion energy conference, Yokohama (Japan), 19-24 Oct 1998; Other Information: PBD: Nov 1998
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION; DOUBLET-3 DEVICE; DIVERTORS; PLASMA SCRAPE-OFF LAYER; EDGE LOCALIZED MODES; PLASMA SIMULATION; PLASMA IMPURITIES; PLASMA DIAGNOSTICS; SHAPE; H-MODE PLASMA CONFINEMENT; PLASMA DRIFT

Citation Formats

Allen, S L, Brooks, N H, and Bastasz, R. Radiative and SOL experiments in open and baffled divertors on DIII-D. United States: N. p., 1998. Web.
Allen, S L, Brooks, N H, & Bastasz, R. Radiative and SOL experiments in open and baffled divertors on DIII-D. United States.
Allen, S L, Brooks, N H, and Bastasz, R. Sun . "Radiative and SOL experiments in open and baffled divertors on DIII-D". United States. https://www.osti.gov/servlets/purl/296835.
@article{osti_296835,
title = {Radiative and SOL experiments in open and baffled divertors on DIII-D},
author = {Allen, S L and Brooks, N H and Bastasz, R},
abstractNote = {The authors present recent progress towards an understanding of the physical processes in the divertor and scrape-off-layer (SOL) plasmas in DIII-D. This has been made possible by a combination of new diagnostics, improved computational models, and changes in divertor geometry. They have focused primarily on ELMing H-mode discharges. The physics of Partially Detached Divertor (PDD) plasmas, with divertor heat flux reduction by divertor radiation enhancement using D{sub 2} puffing, has been studied in 2-D, and a model of the heat and particle transport has been developed that includes conduction, convection, ionization, recombination, and flows. Plasma and impurity particle flows have been measured with Mach probes and spectroscopy and these flows have been compared with the UEDGE model. The model now includes self-consistent calculations of carbon impurities. Impurity radiation has been increased in the divertor and SOL with puff and pump techniques using SOL D{sub 2} puffing, divertor cryopumping, and argon puffing. The important physical processes in plasma-wall interactions have been examined with a DiMES probe, plasma characterization near the divertor plate, and the REDEP code. Experiments comparing single-null (SN) plasma operation in baffled and open divertors have demonstrated a change in the edge plasma profiles. These results are consistent with a reduction in the core ionization source calculated with UEDGE. Divertor particle control in ELMing H-mode with pumping and baffling has resulted in reduction in H-mode core densities to n{sub e}/n{sub gw} {approx} 0.25. Divertor particle exhaust and heat flux has been studied as the plasma shape was varied from a lower SN, to a balanced double null (DN), and finally to an upper SN.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1998},
month = {11}
}

Conference:
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