Impact of perturbative, non-axisymmetric impurity fueling on Alcator C-Mod H-modes

M. L. Reinke; J. D. Lore; J. Terry; D. Brunner; B. LaBombard; B. Lipschultz; A. Hubbard; J. W. Hughes; R. Mumgaard; R. A. Pitts

doi:10.1088/1361-6587/aa8d00

Impact of perturbative, non-axisymmetric impurity fueling on Alcator C-Mod H-modes

M. L. Reinke, J. D. Lore, J. Terry, D. Brunner, B. LaBombard, B. Lipschultz, A. Hubbard, J. W. Hughes, R. Mumgaard, R. A. Pitts

Power Exhaust and Particle Control

Research output: Contribution to journal › Article › peer-review

3 Scopus citations

Abstract

Experiments on Alcator C-Mod have been performed to investigate the impact of toroidally localized impurity injection on H-mode exhaust scenarios. Results help to inform sub-divertor gas injector designs, in particular that of the ITER machine, for which this work was primarily undertaken. In repeated EDA H-modes, the amount of N₂ injected into the private flux region was scanned up to levels which strongly impacted normalized energy confinement, H₉₈, and led to an H/L back-transition. Repeated scans increased the toroidal peaking of the gas injection, reducing from five equally spaced locations to a single toroidal and poloidal injector. Results show the impact on the pedestal and core plasma is similar between all cases as long as the total gas injection rate is held constant. An influence on toroidally localized impurity spectroscopy is shown, demonstrating a complication in using such data in interpreting experiments and supporting boundary modeling in cases where there are localized extrinsic or intrinsic impurity sources. These results, along with prior work in this area on Alcator C-Mod, form a comprehensive set of L-mode and H-mode data to be used for validation of 3D boundary physics codes.

Original language	English
Article number	122002
Journal	Plasma Physics and Controlled Fusion
Volume	59
Issue number	12
DOIs	https://doi.org/10.1088/1361-6587/aa8d00
State	Published - Oct 31 2017

Funding

The authors would like to thank the C-Mod team for expert operation of the facility, and MR would like to highlight the patience of Maria Silveira in configuring the gas injection system for this experiment. This work is supported in part by US Department of Energy award DE-AC05-00OR22725 and DE-FC02-99ER54512, using Alcator C-Mod, a DOE Office of Science User Facility. The views and opinions expressed herein do not necessarily reflect those of the ITER Organization. BL was funded in part by the Wolfson Foundation and UK Royal Society through a Royal Society Wolfson Research Merit Award as well as by the RCUK Energy Programme (EPSRC grant number EP/I501045).

Funders	Funder number
DOE Office of Science
UK Royal Society
US Department of Energy	DE-AC05-00OR22725, DE-FC02-99ER54512
Engineering and Physical Sciences Research Council	EP/I501045
Royal Society
Research Councils UK
Wolfson Foundation

Keywords

axisymmetry
divertor
impurity
tokamak

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.1088/1361-6587/aa8d00

Cite this

@article{410257c7d8a84a95a71812a070089281,

title = "Impact of perturbative, non-axisymmetric impurity fueling on Alcator C-Mod H-modes",

abstract = "Experiments on Alcator C-Mod have been performed to investigate the impact of toroidally localized impurity injection on H-mode exhaust scenarios. Results help to inform sub-divertor gas injector designs, in particular that of the ITER machine, for which this work was primarily undertaken. In repeated EDA H-modes, the amount of N2 injected into the private flux region was scanned up to levels which strongly impacted normalized energy confinement, H98, and led to an H/L back-transition. Repeated scans increased the toroidal peaking of the gas injection, reducing from five equally spaced locations to a single toroidal and poloidal injector. Results show the impact on the pedestal and core plasma is similar between all cases as long as the total gas injection rate is held constant. An influence on toroidally localized impurity spectroscopy is shown, demonstrating a complication in using such data in interpreting experiments and supporting boundary modeling in cases where there are localized extrinsic or intrinsic impurity sources. These results, along with prior work in this area on Alcator C-Mod, form a comprehensive set of L-mode and H-mode data to be used for validation of 3D boundary physics codes.",

keywords = "axisymmetry, divertor, impurity, tokamak",

author = "Reinke, {M. L.} and Lore, {J. D.} and J. Terry and D. Brunner and B. LaBombard and B. Lipschultz and A. Hubbard and Hughes, {J. W.} and R. Mumgaard and Pitts, {R. A.}",

note = "Publisher Copyright: {\textcopyright} 2017 IOP Publishing Ltd.",

year = "2017",

month = oct,

day = "31",

doi = "10.1088/1361-6587/aa8d00",

language = "English",

volume = "59",

journal = "Plasma Physics and Controlled Fusion",

issn = "0741-3335",

publisher = "IOP Publishing",

number = "12",

}

TY - JOUR

T1 - Impact of perturbative, non-axisymmetric impurity fueling on Alcator C-Mod H-modes

AU - Reinke, M. L.

AU - Lore, J. D.

AU - Terry, J.

AU - Brunner, D.

AU - LaBombard, B.

AU - Lipschultz, B.

AU - Hubbard, A.

AU - Hughes, J. W.

AU - Mumgaard, R.

AU - Pitts, R. A.

PY - 2017/10/31

Y1 - 2017/10/31

N2 - Experiments on Alcator C-Mod have been performed to investigate the impact of toroidally localized impurity injection on H-mode exhaust scenarios. Results help to inform sub-divertor gas injector designs, in particular that of the ITER machine, for which this work was primarily undertaken. In repeated EDA H-modes, the amount of N2 injected into the private flux region was scanned up to levels which strongly impacted normalized energy confinement, H98, and led to an H/L back-transition. Repeated scans increased the toroidal peaking of the gas injection, reducing from five equally spaced locations to a single toroidal and poloidal injector. Results show the impact on the pedestal and core plasma is similar between all cases as long as the total gas injection rate is held constant. An influence on toroidally localized impurity spectroscopy is shown, demonstrating a complication in using such data in interpreting experiments and supporting boundary modeling in cases where there are localized extrinsic or intrinsic impurity sources. These results, along with prior work in this area on Alcator C-Mod, form a comprehensive set of L-mode and H-mode data to be used for validation of 3D boundary physics codes.

AB - Experiments on Alcator C-Mod have been performed to investigate the impact of toroidally localized impurity injection on H-mode exhaust scenarios. Results help to inform sub-divertor gas injector designs, in particular that of the ITER machine, for which this work was primarily undertaken. In repeated EDA H-modes, the amount of N2 injected into the private flux region was scanned up to levels which strongly impacted normalized energy confinement, H98, and led to an H/L back-transition. Repeated scans increased the toroidal peaking of the gas injection, reducing from five equally spaced locations to a single toroidal and poloidal injector. Results show the impact on the pedestal and core plasma is similar between all cases as long as the total gas injection rate is held constant. An influence on toroidally localized impurity spectroscopy is shown, demonstrating a complication in using such data in interpreting experiments and supporting boundary modeling in cases where there are localized extrinsic or intrinsic impurity sources. These results, along with prior work in this area on Alcator C-Mod, form a comprehensive set of L-mode and H-mode data to be used for validation of 3D boundary physics codes.

KW - axisymmetry

KW - divertor

KW - impurity

KW - tokamak

UR - http://www.scopus.com/inward/record.url?scp=85034583246&partnerID=8YFLogxK

U2 - 10.1088/1361-6587/aa8d00

DO - 10.1088/1361-6587/aa8d00

M3 - Article

AN - SCOPUS:85034583246

SN - 0741-3335

VL - 59

JO - Plasma Physics and Controlled Fusion

JF - Plasma Physics and Controlled Fusion

IS - 12

M1 - 122002

ER -

Impact of perturbative, non-axisymmetric impurity fueling on Alcator C-Mod H-modes

Abstract

Funding

Keywords

UN SDGs

Access to Document

Other files and links

Fingerprint

Cite this