Impact of ICRF on the scrape-off layer and on plasma wall interactions: From present experiments to fusion reactor

the ASDEX Upgrade Team; the Alcator C-Mod Team, the EUROfusion MST1 Team; JET Contributors; the ASDEX Upgrade Team; the Alcator C-Mod Team, the EUROfusion MST1 Team

doi:10.1016/j.nme.2018.11.017

Impact of ICRF on the scrape-off layer and on plasma wall interactions: From present experiments to fusion reactor

the ASDEX Upgrade Team, the Alcator C-Mod Team, the EUROfusion MST1 Team, JET Contributors, the ASDEX Upgrade Team, the Alcator C-Mod Team, the EUROfusion MST1 Team

Fusion Engineering

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

42 Scopus citations

Abstract

Recent achievements in studies of the effects of ICRF (Ion Cyclotron Range of Frequencies) power on the SOL (Scrape-Off Layer) and PWI (Plasma Wall Interactions) in ASDEX Upgrade (AUG), Alcator C-Mod, and JET-ILW are reviewed. Capabilities to diagnose and model the effect of DC biasing and associated impurity production at active antennas and on magnetic field connections to antennas are described. The experiments show that ICRF near-fields can lead not only to E × B convection, but also to modifications of the SOL density, which for Alcator C-Mod are limited to a narrow region near antenna. On the other hand, the SOL density distribution along with impurity sources can be tailored using local gas injection in AUG and JET-ILW with a positive effect on reduction of impurity sources. The technique of RF image current cancellation at antenna limiters was successfully applied in AUG using the 3-strap AUG antenna and extended to the 4-strap Alcator C-Mod field-aligned antenna. Multiple observations confirmed the reduction of the impact of ICRF on the SOL and on total impurity production when the ratio of the power of the central straps to the total antenna power is in the range 0.6 < P_cen/P_total< 0.8. Near-field calculations indicate that this fairly robust technique can be applied to the ITER ICRF antenna, enabling the mode of operation with reduced PWI. On the contrary, for the A2 antenna in JET-ILW the technique is hindered by RF sheaths excited at the antenna septum. Thus, in order to reduce the effect of ICRF power on PWI in a future fusion reactor, the antenna design has to be optimized along with design of plasma-facing components.

Original language	English
Pages (from-to)	131-140
Number of pages	10
Journal	Nuclear Materials and Energy
Volume	18
DOIs	https://doi.org/10.1016/j.nme.2018.11.017
State	Published - Jan 2019

Funding

This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom Research and Training Programme 2014–2018 under grant agreement No. 633053 . The views and opinions expressed herein do not necessarily reflect those of the European Commission. The work is supported by US DoE, Office of Science, Office of Fusion Energy Sciences, User Facility Alcator C-Mod under DE-FC02-99ER54512 and DE-SC 0010720, and under DOE Contract No. DE-AC05-00OR22725 with UT-Battelle, LLC.

Funders	Funder number
U.S. Department of Energy	DE-AC05-00OR22725
Office of Science
Fusion Energy Sciences	DE-FC02-99ER54512, DE-SC 0010720
Horizon 2020 Framework Programme
H2020 Euratom	633053

Keywords

3-strap
A2 antenna
ASDEX upgrade
Alcator C-Mod
Field-aligned antenna
ICRF
ILA
JET-ILW
Power balance, Three-strap
RF sheath
Sputtering

UN SDGs

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

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10.1016/j.nme.2018.11.017

Cite this

the ASDEX Upgrade Team, the Alcator C-Mod Team, the EUROfusion MST1 Team, JET Contributors, the ASDEX Upgrade Team, & the Alcator C-Mod Team, the EUROfusion MST1 Team (2019). Impact of ICRF on the scrape-off layer and on plasma wall interactions: From present experiments to fusion reactor. Nuclear Materials and Energy, 18, 131-140. https://doi.org/10.1016/j.nme.2018.11.017

@article{0082084f8dbd4848b8755968afffbda1,

title = "Impact of ICRF on the scrape-off layer and on plasma wall interactions: From present experiments to fusion reactor",

abstract = "Recent achievements in studies of the effects of ICRF (Ion Cyclotron Range of Frequencies) power on the SOL (Scrape-Off Layer) and PWI (Plasma Wall Interactions) in ASDEX Upgrade (AUG), Alcator C-Mod, and JET-ILW are reviewed. Capabilities to diagnose and model the effect of DC biasing and associated impurity production at active antennas and on magnetic field connections to antennas are described. The experiments show that ICRF near-fields can lead not only to E × B convection, but also to modifications of the SOL density, which for Alcator C-Mod are limited to a narrow region near antenna. On the other hand, the SOL density distribution along with impurity sources can be tailored using local gas injection in AUG and JET-ILW with a positive effect on reduction of impurity sources. The technique of RF image current cancellation at antenna limiters was successfully applied in AUG using the 3-strap AUG antenna and extended to the 4-strap Alcator C-Mod field-aligned antenna. Multiple observations confirmed the reduction of the impact of ICRF on the SOL and on total impurity production when the ratio of the power of the central straps to the total antenna power is in the range 0.6 < Pcen/Ptotal< 0.8. Near-field calculations indicate that this fairly robust technique can be applied to the ITER ICRF antenna, enabling the mode of operation with reduced PWI. On the contrary, for the A2 antenna in JET-ILW the technique is hindered by RF sheaths excited at the antenna septum. Thus, in order to reduce the effect of ICRF power on PWI in a future fusion reactor, the antenna design has to be optimized along with design of plasma-facing components.",

keywords = "3-strap, A2 antenna, ASDEX upgrade, Alcator C-Mod, Field-aligned antenna, ICRF, ILA, JET-ILW, Power balance, Three-strap, RF sheath, Sputtering",

author = "{the ASDEX Upgrade Team} and {the Alcator C-Mod Team, the EUROfusion MST1 Team} and {JET Contributors} and {the ASDEX Upgrade Team} and {the Alcator C-Mod Team, the EUROfusion MST1 Team} and V. Bobkov and D. Aguiam and R. Bilato and S. Brezinsek and L. Colas and A. Czarnecka and P. Dumortier and R. Dux and H. Faugel and H. F{\"u}nfgelder and Ph Jacquet and A. Kallenbach and A. Krivska and Klepper, {C. C.} and E. Lerche and Y. Lin and D. Milanesio and R. Maggiora and I. Monakhov and R. Neu and Noterdaeme, {J. M.} and R. Ochoukov and Th P{\"u}tterich and M. Reinke and W. Tierens and A. Tuccilo and O. Tudisco and {Van Eester}, D. and J. Wright and S. Wukitch and W. Zhang",

note = "Publisher Copyright: {\textcopyright} 2018 Elsevier Ltd",

year = "2019",

month = jan,

doi = "10.1016/j.nme.2018.11.017",

language = "English",

volume = "18",

pages = "131--140",

journal = "Nuclear Materials and Energy",

issn = "2352-1791",

publisher = "Elsevier",

}

the ASDEX Upgrade Team, the Alcator C-Mod Team, the EUROfusion MST1 Team, JET Contributors, the ASDEX Upgrade Team & the Alcator C-Mod Team, the EUROfusion MST1 Team 2019, 'Impact of ICRF on the scrape-off layer and on plasma wall interactions: From present experiments to fusion reactor', Nuclear Materials and Energy, vol. 18, pp. 131-140. https://doi.org/10.1016/j.nme.2018.11.017

TY - JOUR

T1 - Impact of ICRF on the scrape-off layer and on plasma wall interactions

T2 - From present experiments to fusion reactor

AU - the ASDEX Upgrade Team

AU - the Alcator C-Mod Team, the EUROfusion MST1 Team

AU - JET Contributors

AU - the ASDEX Upgrade Team

AU - the Alcator C-Mod Team, the EUROfusion MST1 Team

AU - Bobkov, V.

AU - Aguiam, D.

AU - Bilato, R.

AU - Brezinsek, S.

AU - Colas, L.

AU - Czarnecka, A.

AU - Dumortier, P.

AU - Dux, R.

AU - Faugel, H.

AU - Fünfgelder, H.

AU - Jacquet, Ph

AU - Kallenbach, A.

AU - Krivska, A.

AU - Klepper, C. C.

AU - Lerche, E.

AU - Lin, Y.

AU - Milanesio, D.

AU - Maggiora, R.

AU - Monakhov, I.

AU - Neu, R.

AU - Noterdaeme, J. M.

AU - Ochoukov, R.

AU - Pütterich, Th

AU - Reinke, M.

AU - Tierens, W.

AU - Tuccilo, A.

AU - Tudisco, O.

AU - Van Eester, D.

AU - Wright, J.

AU - Wukitch, S.

AU - Zhang, W.

PY - 2019/1

Y1 - 2019/1

N2 - Recent achievements in studies of the effects of ICRF (Ion Cyclotron Range of Frequencies) power on the SOL (Scrape-Off Layer) and PWI (Plasma Wall Interactions) in ASDEX Upgrade (AUG), Alcator C-Mod, and JET-ILW are reviewed. Capabilities to diagnose and model the effect of DC biasing and associated impurity production at active antennas and on magnetic field connections to antennas are described. The experiments show that ICRF near-fields can lead not only to E × B convection, but also to modifications of the SOL density, which for Alcator C-Mod are limited to a narrow region near antenna. On the other hand, the SOL density distribution along with impurity sources can be tailored using local gas injection in AUG and JET-ILW with a positive effect on reduction of impurity sources. The technique of RF image current cancellation at antenna limiters was successfully applied in AUG using the 3-strap AUG antenna and extended to the 4-strap Alcator C-Mod field-aligned antenna. Multiple observations confirmed the reduction of the impact of ICRF on the SOL and on total impurity production when the ratio of the power of the central straps to the total antenna power is in the range 0.6 < Pcen/Ptotal< 0.8. Near-field calculations indicate that this fairly robust technique can be applied to the ITER ICRF antenna, enabling the mode of operation with reduced PWI. On the contrary, for the A2 antenna in JET-ILW the technique is hindered by RF sheaths excited at the antenna septum. Thus, in order to reduce the effect of ICRF power on PWI in a future fusion reactor, the antenna design has to be optimized along with design of plasma-facing components.

AB - Recent achievements in studies of the effects of ICRF (Ion Cyclotron Range of Frequencies) power on the SOL (Scrape-Off Layer) and PWI (Plasma Wall Interactions) in ASDEX Upgrade (AUG), Alcator C-Mod, and JET-ILW are reviewed. Capabilities to diagnose and model the effect of DC biasing and associated impurity production at active antennas and on magnetic field connections to antennas are described. The experiments show that ICRF near-fields can lead not only to E × B convection, but also to modifications of the SOL density, which for Alcator C-Mod are limited to a narrow region near antenna. On the other hand, the SOL density distribution along with impurity sources can be tailored using local gas injection in AUG and JET-ILW with a positive effect on reduction of impurity sources. The technique of RF image current cancellation at antenna limiters was successfully applied in AUG using the 3-strap AUG antenna and extended to the 4-strap Alcator C-Mod field-aligned antenna. Multiple observations confirmed the reduction of the impact of ICRF on the SOL and on total impurity production when the ratio of the power of the central straps to the total antenna power is in the range 0.6 < Pcen/Ptotal< 0.8. Near-field calculations indicate that this fairly robust technique can be applied to the ITER ICRF antenna, enabling the mode of operation with reduced PWI. On the contrary, for the A2 antenna in JET-ILW the technique is hindered by RF sheaths excited at the antenna septum. Thus, in order to reduce the effect of ICRF power on PWI in a future fusion reactor, the antenna design has to be optimized along with design of plasma-facing components.

KW - 3-strap

KW - A2 antenna

KW - ASDEX upgrade

KW - Alcator C-Mod

KW - Field-aligned antenna

KW - ICRF

KW - ILA

KW - JET-ILW

KW - Power balance, Three-strap

KW - RF sheath

KW - Sputtering

UR - http://www.scopus.com/inward/record.url?scp=85059039214&partnerID=8YFLogxK

U2 - 10.1016/j.nme.2018.11.017

DO - 10.1016/j.nme.2018.11.017

M3 - Article

AN - SCOPUS:85059039214

SN - 2352-1791

VL - 18

SP - 131

EP - 140

JO - Nuclear Materials and Energy

JF - Nuclear Materials and Energy

ER -

Impact of ICRF on the scrape-off layer and on plasma wall interactions: From present experiments to fusion reactor

Abstract

Funding

Keywords

UN SDGs

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