LH and ICRF driven scrape-off-layer density modifications and their impact on LH coupling on Alcator C-Mod

C. Lau; Y. Lin; G. R. Hanson; G. Wallace; S. J. Wukitch; B. Labombard; R. Ochoukov; S. Shiraiwa; J. Terry; J. Wilgen

doi:10.1063/1.4864575

LH and ICRF driven scrape-off-layer density modifications and their impact on LH coupling on Alcator C-Mod

C. Lau, Y. Lin, G. R. Hanson, G. Wallace, S. J. Wukitch, B. Labombard, R. Ochoukov, S. Shiraiwa, J. Terry, J. Wilgen

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

2 Scopus citations

Abstract

Studies of scrape-off-layer (SOL) density profiles by a reflectometer at three poloidal locations adjacent to the lower hybrid (LH) launcher show that for a wide range of plasma parameters, the application of either LH power only or combined with ion cyclotron range of frequencies (ICRF) power induces large modifications on SOL profiles and also creates strong poloidal density striations. With density striations, calculating LH reflection coefficient assuming a poloidally uniform density profile becomes inadequate to represent experimental conditions. The experimentally measured LH reflection coefficient appears to be close to that calculated using the measured density profile in front of the waveguide mouth, where strong density depletion is observed. Using profiles from other locations can result in a factor of 2 too low in reflection coefficient calculation. The poloidal density striations with LH power can be reproduced by a 2-D diffusive-convective model that includes the dynamics of the LH induced E×B convective eddies. Adding ICRF power, the density modifications and striations become more complicated and often lead to worse LH coupling, especially in cases that the ICRF antenna is magnetically connected to the LH launcher.

Original language	English
Title of host publication	Radiofrequency Power in Plasmas - Proceedings of the 20th Topical Conference
Publisher	American Institute of Physics Inc.
Pages	410-413
Number of pages	4
ISBN (Print)	9780735412101
DOIs	https://doi.org/10.1063/1.4864575
State	Published - 2014
Externally published	Yes
Event	20th Topical Conference on Radiofrequency Power in Plasmas - Sorrento, Italy Duration: Jun 25 2013 → Jun 28 2013

Publication series

Name	AIP Conference Proceedings
Volume	1580
ISSN (Print)	0094-243X
ISSN (Electronic)	1551-7616

Conference

Conference	20th Topical Conference on Radiofrequency Power in Plasmas
Country/Territory	Italy
City	Sorrento
Period	06/25/13 → 06/28/13

Funding

Funders	Funder number
Oak Ridge National Laboratory

Keywords

ICRF
LH coupling
Lower Hybrid
SOL
density profile
et al.cator C-Mod
reflectometer

UN SDGs

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

Access to Document

10.1063/1.4864575

Cite this

Lau, C., Lin, Y., Hanson, G. R., Wallace, G., Wukitch, S. J., Labombard, B., Ochoukov, R., Shiraiwa, S., Terry, J., & Wilgen, J. (2014). LH and ICRF driven scrape-off-layer density modifications and their impact on LH coupling on Alcator C-Mod. In Radiofrequency Power in Plasmas - Proceedings of the 20th Topical Conference (pp. 410-413). (AIP Conference Proceedings; Vol. 1580). American Institute of Physics Inc.. https://doi.org/10.1063/1.4864575

@inproceedings{29be935159b04a5a8bdc1f637751f071,

title = "LH and ICRF driven scrape-off-layer density modifications and their impact on LH coupling on Alcator C-Mod",

abstract = "Studies of scrape-off-layer (SOL) density profiles by a reflectometer at three poloidal locations adjacent to the lower hybrid (LH) launcher show that for a wide range of plasma parameters, the application of either LH power only or combined with ion cyclotron range of frequencies (ICRF) power induces large modifications on SOL profiles and also creates strong poloidal density striations. With density striations, calculating LH reflection coefficient assuming a poloidally uniform density profile becomes inadequate to represent experimental conditions. The experimentally measured LH reflection coefficient appears to be close to that calculated using the measured density profile in front of the waveguide mouth, where strong density depletion is observed. Using profiles from other locations can result in a factor of 2 too low in reflection coefficient calculation. The poloidal density striations with LH power can be reproduced by a 2-D diffusive-convective model that includes the dynamics of the LH induced E×B convective eddies. Adding ICRF power, the density modifications and striations become more complicated and often lead to worse LH coupling, especially in cases that the ICRF antenna is magnetically connected to the LH launcher.",

keywords = "ICRF, LH coupling, Lower Hybrid, SOL, density profile, et al.cator C-Mod, reflectometer",

author = "C. Lau and Y. Lin and Hanson, {G. R.} and G. Wallace and Wukitch, {S. J.} and B. Labombard and R. Ochoukov and S. Shiraiwa and J. Terry and J. Wilgen",

year = "2014",

doi = "10.1063/1.4864575",

language = "English",

isbn = "9780735412101",

series = "AIP Conference Proceedings",

publisher = "American Institute of Physics Inc.",

pages = "410--413",

booktitle = "Radiofrequency Power in Plasmas - Proceedings of the 20th Topical Conference",

note = "20th Topical Conference on Radiofrequency Power in Plasmas ; Conference date: 25-06-2013 Through 28-06-2013",

}

Lau, C, Lin, Y, Hanson, GR, Wallace, G, Wukitch, SJ, Labombard, B, Ochoukov, R, Shiraiwa, S, Terry, J & Wilgen, J 2014, LH and ICRF driven scrape-off-layer density modifications and their impact on LH coupling on Alcator C-Mod. in Radiofrequency Power in Plasmas - Proceedings of the 20th Topical Conference. AIP Conference Proceedings, vol. 1580, American Institute of Physics Inc., pp. 410-413, 20th Topical Conference on Radiofrequency Power in Plasmas, Sorrento, Italy, 06/25/13. https://doi.org/10.1063/1.4864575

LH and ICRF driven scrape-off-layer density modifications and their impact on LH coupling on Alcator C-Mod. / Lau, C.; Lin, Y.; Hanson, G. R. et al.
Radiofrequency Power in Plasmas - Proceedings of the 20th Topical Conference. American Institute of Physics Inc., 2014. p. 410-413 (AIP Conference Proceedings; Vol. 1580).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

TY - GEN

T1 - LH and ICRF driven scrape-off-layer density modifications and their impact on LH coupling on Alcator C-Mod

AU - Lau, C.

AU - Lin, Y.

AU - Hanson, G. R.

AU - Wallace, G.

AU - Wukitch, S. J.

AU - Labombard, B.

AU - Ochoukov, R.

AU - Shiraiwa, S.

AU - Terry, J.

AU - Wilgen, J.

PY - 2014

Y1 - 2014

N2 - Studies of scrape-off-layer (SOL) density profiles by a reflectometer at three poloidal locations adjacent to the lower hybrid (LH) launcher show that for a wide range of plasma parameters, the application of either LH power only or combined with ion cyclotron range of frequencies (ICRF) power induces large modifications on SOL profiles and also creates strong poloidal density striations. With density striations, calculating LH reflection coefficient assuming a poloidally uniform density profile becomes inadequate to represent experimental conditions. The experimentally measured LH reflection coefficient appears to be close to that calculated using the measured density profile in front of the waveguide mouth, where strong density depletion is observed. Using profiles from other locations can result in a factor of 2 too low in reflection coefficient calculation. The poloidal density striations with LH power can be reproduced by a 2-D diffusive-convective model that includes the dynamics of the LH induced E×B convective eddies. Adding ICRF power, the density modifications and striations become more complicated and often lead to worse LH coupling, especially in cases that the ICRF antenna is magnetically connected to the LH launcher.

AB - Studies of scrape-off-layer (SOL) density profiles by a reflectometer at three poloidal locations adjacent to the lower hybrid (LH) launcher show that for a wide range of plasma parameters, the application of either LH power only or combined with ion cyclotron range of frequencies (ICRF) power induces large modifications on SOL profiles and also creates strong poloidal density striations. With density striations, calculating LH reflection coefficient assuming a poloidally uniform density profile becomes inadequate to represent experimental conditions. The experimentally measured LH reflection coefficient appears to be close to that calculated using the measured density profile in front of the waveguide mouth, where strong density depletion is observed. Using profiles from other locations can result in a factor of 2 too low in reflection coefficient calculation. The poloidal density striations with LH power can be reproduced by a 2-D diffusive-convective model that includes the dynamics of the LH induced E×B convective eddies. Adding ICRF power, the density modifications and striations become more complicated and often lead to worse LH coupling, especially in cases that the ICRF antenna is magnetically connected to the LH launcher.

KW - ICRF

KW - LH coupling

KW - Lower Hybrid

KW - SOL

KW - density profile

KW - et al.cator C-Mod

KW - reflectometer

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U2 - 10.1063/1.4864575

DO - 10.1063/1.4864575

M3 - Conference contribution

AN - SCOPUS:84906351401

SN - 9780735412101

T3 - AIP Conference Proceedings

SP - 410

EP - 413

BT - Radiofrequency Power in Plasmas - Proceedings of the 20th Topical Conference

PB - American Institute of Physics Inc.

T2 - 20th Topical Conference on Radiofrequency Power in Plasmas

Y2 - 25 June 2013 through 28 June 2013

ER -

LH and ICRF driven scrape-off-layer density modifications and their impact on LH coupling on Alcator C-Mod

Abstract

Publication series

Conference

Funding

Keywords

UN SDGs

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