Effect of the scrape-off layer in AORSA full wave simulations of fast wave minority, mid/high harmonic, and helicon heating regimes

N. Bertelli; E. F. Jaeger; C. Lau; D. Blazevski; D. L. Green; L. Berry; P. T. Bonoli; S. Gerhardt; J. C. Hosea; B. Leblanc; R. J. Perkins; C. K. Phillips; R. I. Pinsker; R. Prater; C. M. Qin; P. M. Ryan; G. Taylor; E. J. Valeo; J. R. Wilson; J. C. Wright; X. J. Zhang

doi:10.1063/1.4936475

Effect of the scrape-off layer in AORSA full wave simulations of fast wave minority, mid/high harmonic, and helicon heating regimes

N. Bertelli, E. F. Jaeger, C. Lau, D. Blazevski, D. L. Green, L. Berry, P. T. Bonoli, S. Gerhardt, J. C. Hosea, B. Leblanc, R. J. Perkins, C. K. Phillips, R. I. Pinsker, R. Prater, C. M. Qin, P. M. Ryan, G. Taylor, E. J. Valeo, J. R. Wilson, J. C. WrightX. J. Zhang

Diagnostics and Control

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

3 Scopus citations

Abstract

Several experiments on different machines and in different fast wave (FW) heating regimes, such as hydrogen minority heating and high harmonic fast waves, have found strong interactions between radio-frequency (RF) waves and the scrape-off layer (SOL) region. This paper examines the propagation and the power loss in the SOL by using the full wave code AORSA, in which the edge plasma beyond the last closed flux surface (LCFS) is included in the solution domain and a collisional damping parameter is used as a proxy to represent the real, and most likely nonlinear, damping processes. 3D AORSA results for the National Spherical Torus eXperiment (NSTX), where a full antenna spectrum is reconstructed, are shown, confirming the same behavior found for a single toroidal mode results in Bertelli et al, Nucl. Fusion, 54 083004, 2014, namely, a strong transition to higher SOL power losses (driven by the RF field) when the FW cut-off is moved away from in front of the antenna by increasing the edge density. Additionally, full wave simulations have been extended to "conventional" tokamaks with higher aspect ratios, such as the DIII-D, Alcator C-Mod, and EAST devices. DIII-D results show similar behavior found in NSTX and NSTX-U, consistent with previous DIII-D experimental observations. In contrast, a different behavior has been found for Alcator C-Mod and EAST, which operate in the minority heating regime unlike NSTX/NSTX-U and DIII-D, which operate in the mid/high harmonic regime. A substantial discussion of some of the main aspects, such as (i) the pitch angle of the magnetic field; (ii) minority heating vs. mid/high harmonic regimes is presented showing the different behavior of the RF field in the SOL region for NSTX-U scenarios with different plasma current. Finally, the preliminary results of the impact of the SOL region on the evaluation of the helicon current drive efficiency in DIII-D is presented for the first time and briefly compared with the different regimes mentioned above.

Original language	English
Title of host publication	Radio Frequency Power in Plasmas
Subtitle of host publication	Proceedings of the 21St Topical Conference
Editors	Robert I. Pinsker
Publisher	American Institute of Physics Inc.
ISBN (Electronic)	9780735413368
DOIs	https://doi.org/10.1063/1.4936475
State	Published - Dec 10 2015
Event	21st Topical Conference on Radiofrequency Power in Plasmas - Lake Arrowhead, United States Duration: Apr 27 2015 → Apr 29 2015

Publication series

Name	AIP Conference Proceedings
Volume	1689
ISSN (Print)	0094-243X
ISSN (Electronic)	1551-7616

Conference

Conference	21st Topical Conference on Radiofrequency Power in Plasmas
Country/Territory	United States
City	Lake Arrowhead
Period	04/27/15 → 04/29/15

Funding

This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences under contract numbers DE-FC02-01ER54648, DE-AC02-09CH11466, and DEAC02-05CH11231.

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10.1063/1.4936475

Cite this

Bertelli, N., Jaeger, E. F., Lau, C., Blazevski, D., Green, D. L., Berry, L., Bonoli, P. T., Gerhardt, S., Hosea, J. C., Leblanc, B., Perkins, R. J., Phillips, C. K., Pinsker, R. I., Prater, R., Qin, C. M., Ryan, P. M., Taylor, G., Valeo, E. J., Wilson, J. R., ... Zhang, X. J. (2015). Effect of the scrape-off layer in AORSA full wave simulations of fast wave minority, mid/high harmonic, and helicon heating regimes. In R. I. Pinsker (Ed.), Radio Frequency Power in Plasmas: Proceedings of the 21St Topical Conference Article 030010 (AIP Conference Proceedings; Vol. 1689). American Institute of Physics Inc.. https://doi.org/10.1063/1.4936475

@inproceedings{dac628d680ef446c87972ba1eee64028,

title = "Effect of the scrape-off layer in AORSA full wave simulations of fast wave minority, mid/high harmonic, and helicon heating regimes",

abstract = "Several experiments on different machines and in different fast wave (FW) heating regimes, such as hydrogen minority heating and high harmonic fast waves, have found strong interactions between radio-frequency (RF) waves and the scrape-off layer (SOL) region. This paper examines the propagation and the power loss in the SOL by using the full wave code AORSA, in which the edge plasma beyond the last closed flux surface (LCFS) is included in the solution domain and a collisional damping parameter is used as a proxy to represent the real, and most likely nonlinear, damping processes. 3D AORSA results for the National Spherical Torus eXperiment (NSTX), where a full antenna spectrum is reconstructed, are shown, confirming the same behavior found for a single toroidal mode results in Bertelli et al, Nucl. Fusion, 54 083004, 2014, namely, a strong transition to higher SOL power losses (driven by the RF field) when the FW cut-off is moved away from in front of the antenna by increasing the edge density. Additionally, full wave simulations have been extended to {"}conventional{"} tokamaks with higher aspect ratios, such as the DIII-D, Alcator C-Mod, and EAST devices. DIII-D results show similar behavior found in NSTX and NSTX-U, consistent with previous DIII-D experimental observations. In contrast, a different behavior has been found for Alcator C-Mod and EAST, which operate in the minority heating regime unlike NSTX/NSTX-U and DIII-D, which operate in the mid/high harmonic regime. A substantial discussion of some of the main aspects, such as (i) the pitch angle of the magnetic field; (ii) minority heating vs. mid/high harmonic regimes is presented showing the different behavior of the RF field in the SOL region for NSTX-U scenarios with different plasma current. Finally, the preliminary results of the impact of the SOL region on the evaluation of the helicon current drive efficiency in DIII-D is presented for the first time and briefly compared with the different regimes mentioned above.",

author = "N. Bertelli and Jaeger, {E. F.} and C. Lau and D. Blazevski and Green, {D. L.} and L. Berry and Bonoli, {P. T.} and S. Gerhardt and Hosea, {J. C.} and B. Leblanc and Perkins, {R. J.} and Phillips, {C. K.} and Pinsker, {R. I.} and R. Prater and Qin, {C. M.} and Ryan, {P. M.} and G. Taylor and Valeo, {E. J.} and Wilson, {J. R.} and Wright, {J. C.} and Zhang, {X. J.}",

note = "Publisher Copyright: {\textcopyright} 2015 AIP Publishing LLC.; 21st Topical Conference on Radiofrequency Power in Plasmas ; Conference date: 27-04-2015 Through 29-04-2015",

year = "2015",

month = dec,

day = "10",

doi = "10.1063/1.4936475",

language = "English",

series = "AIP Conference Proceedings",

publisher = "American Institute of Physics Inc.",

editor = "Pinsker, {Robert I.}",

booktitle = "Radio Frequency Power in Plasmas",

}

Bertelli, N, Jaeger, EF, Lau, C, Blazevski, D, Green, DL, Berry, L, Bonoli, PT, Gerhardt, S, Hosea, JC, Leblanc, B, Perkins, RJ, Phillips, CK, Pinsker, RI, Prater, R, Qin, CM, Ryan, PM, Taylor, G, Valeo, EJ, Wilson, JR, Wright, JC & Zhang, XJ 2015, Effect of the scrape-off layer in AORSA full wave simulations of fast wave minority, mid/high harmonic, and helicon heating regimes. in RI Pinsker (ed.), Radio Frequency Power in Plasmas: Proceedings of the 21St Topical Conference., 030010, AIP Conference Proceedings, vol. 1689, American Institute of Physics Inc., 21st Topical Conference on Radiofrequency Power in Plasmas, Lake Arrowhead, United States, 04/27/15. https://doi.org/10.1063/1.4936475

Effect of the scrape-off layer in AORSA full wave simulations of fast wave minority, mid/high harmonic, and helicon heating regimes. / Bertelli, N.; Jaeger, E. F.; Lau, C. et al.
Radio Frequency Power in Plasmas: Proceedings of the 21St Topical Conference. ed. / Robert I. Pinsker. American Institute of Physics Inc., 2015. 030010 (AIP Conference Proceedings; Vol. 1689).

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

TY - GEN

T1 - Effect of the scrape-off layer in AORSA full wave simulations of fast wave minority, mid/high harmonic, and helicon heating regimes

AU - Bertelli, N.

AU - Jaeger, E. F.

AU - Lau, C.

AU - Blazevski, D.

AU - Green, D. L.

AU - Berry, L.

AU - Bonoli, P. T.

AU - Gerhardt, S.

AU - Hosea, J. C.

AU - Leblanc, B.

AU - Perkins, R. J.

AU - Phillips, C. K.

AU - Pinsker, R. I.

AU - Prater, R.

AU - Qin, C. M.

AU - Ryan, P. M.

AU - Taylor, G.

AU - Valeo, E. J.

AU - Wilson, J. R.

AU - Wright, J. C.

AU - Zhang, X. J.

PY - 2015/12/10

Y1 - 2015/12/10

N2 - Several experiments on different machines and in different fast wave (FW) heating regimes, such as hydrogen minority heating and high harmonic fast waves, have found strong interactions between radio-frequency (RF) waves and the scrape-off layer (SOL) region. This paper examines the propagation and the power loss in the SOL by using the full wave code AORSA, in which the edge plasma beyond the last closed flux surface (LCFS) is included in the solution domain and a collisional damping parameter is used as a proxy to represent the real, and most likely nonlinear, damping processes. 3D AORSA results for the National Spherical Torus eXperiment (NSTX), where a full antenna spectrum is reconstructed, are shown, confirming the same behavior found for a single toroidal mode results in Bertelli et al, Nucl. Fusion, 54 083004, 2014, namely, a strong transition to higher SOL power losses (driven by the RF field) when the FW cut-off is moved away from in front of the antenna by increasing the edge density. Additionally, full wave simulations have been extended to "conventional" tokamaks with higher aspect ratios, such as the DIII-D, Alcator C-Mod, and EAST devices. DIII-D results show similar behavior found in NSTX and NSTX-U, consistent with previous DIII-D experimental observations. In contrast, a different behavior has been found for Alcator C-Mod and EAST, which operate in the minority heating regime unlike NSTX/NSTX-U and DIII-D, which operate in the mid/high harmonic regime. A substantial discussion of some of the main aspects, such as (i) the pitch angle of the magnetic field; (ii) minority heating vs. mid/high harmonic regimes is presented showing the different behavior of the RF field in the SOL region for NSTX-U scenarios with different plasma current. Finally, the preliminary results of the impact of the SOL region on the evaluation of the helicon current drive efficiency in DIII-D is presented for the first time and briefly compared with the different regimes mentioned above.

AB - Several experiments on different machines and in different fast wave (FW) heating regimes, such as hydrogen minority heating and high harmonic fast waves, have found strong interactions between radio-frequency (RF) waves and the scrape-off layer (SOL) region. This paper examines the propagation and the power loss in the SOL by using the full wave code AORSA, in which the edge plasma beyond the last closed flux surface (LCFS) is included in the solution domain and a collisional damping parameter is used as a proxy to represent the real, and most likely nonlinear, damping processes. 3D AORSA results for the National Spherical Torus eXperiment (NSTX), where a full antenna spectrum is reconstructed, are shown, confirming the same behavior found for a single toroidal mode results in Bertelli et al, Nucl. Fusion, 54 083004, 2014, namely, a strong transition to higher SOL power losses (driven by the RF field) when the FW cut-off is moved away from in front of the antenna by increasing the edge density. Additionally, full wave simulations have been extended to "conventional" tokamaks with higher aspect ratios, such as the DIII-D, Alcator C-Mod, and EAST devices. DIII-D results show similar behavior found in NSTX and NSTX-U, consistent with previous DIII-D experimental observations. In contrast, a different behavior has been found for Alcator C-Mod and EAST, which operate in the minority heating regime unlike NSTX/NSTX-U and DIII-D, which operate in the mid/high harmonic regime. A substantial discussion of some of the main aspects, such as (i) the pitch angle of the magnetic field; (ii) minority heating vs. mid/high harmonic regimes is presented showing the different behavior of the RF field in the SOL region for NSTX-U scenarios with different plasma current. Finally, the preliminary results of the impact of the SOL region on the evaluation of the helicon current drive efficiency in DIII-D is presented for the first time and briefly compared with the different regimes mentioned above.

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U2 - 10.1063/1.4936475

DO - 10.1063/1.4936475

M3 - Conference contribution

AN - SCOPUS:84984535787

T3 - AIP Conference Proceedings

BT - Radio Frequency Power in Plasmas

A2 - Pinsker, Robert I.

PB - American Institute of Physics Inc.

T2 - 21st Topical Conference on Radiofrequency Power in Plasmas

Y2 - 27 April 2015 through 29 April 2015

ER -

Bertelli N, Jaeger EF, Lau C, Blazevski D, Green DL, Berry L et al. Effect of the scrape-off layer in AORSA full wave simulations of fast wave minority, mid/high harmonic, and helicon heating regimes. In Pinsker RI, editor, Radio Frequency Power in Plasmas: Proceedings of the 21St Topical Conference. American Institute of Physics Inc. 2015. 030010. (AIP Conference Proceedings). doi: 10.1063/1.4936475

Effect of the scrape-off layer in AORSA full wave simulations of fast wave minority, mid/high harmonic, and helicon heating regimes

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