Overview of ASDEX upgrade results

D. Aguiam, Leena Aho-Mantila, C. Angioni, N. Arden, R. Arredondo Parra, O. Asunta, M. De Baar, M. Balden, K. Behler, A. Bergmann, J. Bernardo, M. Bernert, M. Beurskens, A. Biancalani, R. Bilato, G. Birkenmeier, V. Bobkov, A. Bock, A. Bogomolov, T. BolzonellaB. Böswirth, C. Bottereau, A. Bottino, H. Van Den Brand, S. Brezinsek, D. Brida, F. Brochard, C. Bruhn, J. Buchanan, A. Buhler, A. Burckhart, D. Cambon-Silva, Y. Camenen, P. Carvalho, G. Carrasco, C. Cazzaniga, M. Carr, D. Carralero, L. Casali, C. Castaldo, M. Cavedon, C. Challis, A. Chankin, I. Chapman, F. Clairet, I. Classen, S. Coda, R. Coelho, Antti H. Hakola, Antti Salmi, A. Kallenbach, ASDEX Upgrade Team,

Research output: Contribution to journalReview ArticleScientificpeer-review

22 Citations (Scopus)

Abstract

The ASDEX Upgrade (AUG) programme is directed towards physics input to critical elements of the ITER design and the preparation of ITER operation, as well as addressing physics issues for a future DEMO design. Since 2015, AUG is equipped with a new pair of 3-strap ICRF antennas, which were designed for a reduction of tungsten release during ICRF operation. As predicted, a factor two reduction on the ICRF-induced W plasma content could be achieved by the reduction of the sheath voltage at the antenna limiters via the compensation of the image currents of the central and side straps in the antenna frame. There are two main operational scenario lines in AUG. Experiments with low collisionality, which comprise current drive, ELM mitigation/suppression and fast ion physics, are mainly done with freshly boronized walls to reduce the tungsten influx at these high edge temperature conditions. Full ELM suppression and non-inductive operation up to a plasma current of Ip = 0.8 MA could be obtained at low plasma density. Plasma exhaust is studied under conditions of high neutral divertor pressure and separatrix electron density, where a fresh boronization is not required. Substantial progress could be achieved for the understanding of the confinement degradation by strong D puffing and the improvement with nitrogen or carbon seeding. Inward/outward shifts of the electron density profile relative to the temperature profile effect the edge stability via the pressure profile changes and lead to improved/decreased pedestal performance. Seeding and D gas puffing are found to effect the core fueling via changes in a region of high density on the high field side (HFSHD). The integration of all above mentioned operational scenarios will be feasible and naturally obtained in a large device where the edge is more opaque for neutrals and higher plasma temperatures provide a lower collisionality. The combination of exhaust control with pellet fueling has been successfully demonstrated. High divertor enrichment values of nitrogen EN ≥ 10 have been obtained during pellet injection, which is a prerequisite for the simultaneous achievement of good core plasma purity and high divertor radiation levels. Impurity accumulation observed in the all-metal AUG device caused by the strong neoclassical inward transport of tungsten in the pedestal is expected to be relieved by the higher neoclassical temperature screening in larger devices.

Original languageEnglish
Article number102015
JournalNuclear Fusion
Volume57
Issue number10
DOIs
Publication statusPublished - 28 Jun 2017
MoE publication typeA2 Review article in a scientific journal

Fingerprint

straps
tungsten
refueling
antennas
inoculation
pellets
physics
retarding
nitrogen
electron density profiles
plasma currents
high temperature plasmas
sheaths
temperature profiles
plasma density
purity
screening
injection
degradation
impurities

Keywords

  • DEMO
  • ITER
  • nuclear fusion
  • tokamak physics

Cite this

Aguiam, D., Aho-Mantila, L., Angioni, C., Arden, N., Arredondo Parra, R., Asunta, O. (2017). Overview of ASDEX upgrade results. Nuclear Fusion, 57(10), [102015]. https://doi.org/10.1088/1741-4326/aa64f6
Aguiam, D. ; Aho-Mantila, Leena ; Angioni, C. ; Arden, N. ; Arredondo Parra, R. ; Asunta, O. ; De Baar, M. ; Balden, M. ; Behler, K. ; Bergmann, A. ; Bernardo, J. ; Bernert, M. ; Beurskens, M. ; Biancalani, A. ; Bilato, R. ; Birkenmeier, G. ; Bobkov, V. ; Bock, A. ; Bogomolov, A. ; Bolzonella, T. ; Böswirth, B. ; Bottereau, C. ; Bottino, A. ; Van Den Brand, H. ; Brezinsek, S. ; Brida, D. ; Brochard, F. ; Bruhn, C. ; Buchanan, J. ; Buhler, A. ; Burckhart, A. ; Cambon-Silva, D. ; Camenen, Y. ; Carvalho, P. ; Carrasco, G. ; Cazzaniga, C. ; Carr, M. ; Carralero, D. ; Casali, L. ; Castaldo, C. ; Cavedon, M. ; Challis, C. ; Chankin, A. ; Chapman, I. ; Clairet, F. ; Classen, I. ; Coda, S. ; Coelho, R. ; Hakola, Antti H. ; Salmi, Antti ; Kallenbach, A. ; ASDEX Upgrade Team. / Overview of ASDEX upgrade results. In: Nuclear Fusion. 2017 ; Vol. 57, No. 10.
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abstract = "The ASDEX Upgrade (AUG) programme is directed towards physics input to critical elements of the ITER design and the preparation of ITER operation, as well as addressing physics issues for a future DEMO design. Since 2015, AUG is equipped with a new pair of 3-strap ICRF antennas, which were designed for a reduction of tungsten release during ICRF operation. As predicted, a factor two reduction on the ICRF-induced W plasma content could be achieved by the reduction of the sheath voltage at the antenna limiters via the compensation of the image currents of the central and side straps in the antenna frame. There are two main operational scenario lines in AUG. Experiments with low collisionality, which comprise current drive, ELM mitigation/suppression and fast ion physics, are mainly done with freshly boronized walls to reduce the tungsten influx at these high edge temperature conditions. Full ELM suppression and non-inductive operation up to a plasma current of Ip = 0.8 MA could be obtained at low plasma density. Plasma exhaust is studied under conditions of high neutral divertor pressure and separatrix electron density, where a fresh boronization is not required. Substantial progress could be achieved for the understanding of the confinement degradation by strong D puffing and the improvement with nitrogen or carbon seeding. Inward/outward shifts of the electron density profile relative to the temperature profile effect the edge stability via the pressure profile changes and lead to improved/decreased pedestal performance. Seeding and D gas puffing are found to effect the core fueling via changes in a region of high density on the high field side (HFSHD). The integration of all above mentioned operational scenarios will be feasible and naturally obtained in a large device where the edge is more opaque for neutrals and higher plasma temperatures provide a lower collisionality. The combination of exhaust control with pellet fueling has been successfully demonstrated. High divertor enrichment values of nitrogen EN ≥ 10 have been obtained during pellet injection, which is a prerequisite for the simultaneous achievement of good core plasma purity and high divertor radiation levels. Impurity accumulation observed in the all-metal AUG device caused by the strong neoclassical inward transport of tungsten in the pedestal is expected to be relieved by the higher neoclassical temperature screening in larger devices.",
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Aguiam, D, Aho-Mantila, L, Angioni, C, Arden, N, Arredondo Parra, R, Asunta, O, De Baar, M, Balden, M, Behler, K, Bergmann, A, Bernardo, J, Bernert, M, Beurskens, M, Biancalani, A, Bilato, R, Birkenmeier, G, Bobkov, V, Bock, A, Bogomolov, A, Bolzonella, T, Böswirth, B, Bottereau, C, Bottino, A, Van Den Brand, H, Brezinsek, S, Brida, D, Brochard, F, Bruhn, C, Buchanan, J, Buhler, A, Burckhart, A, Cambon-Silva, D, Camenen, Y, Carvalho, P, Carrasco, G, Cazzaniga, C, Carr, M, Carralero, D, Casali, L, Castaldo, C, Cavedon, M, Challis, C, Chankin, A, Chapman, I, Clairet, F, Classen, I, Coda, S, Coelho, R, Hakola, AH, Salmi, A, Kallenbach, A, ASDEX Upgrade Team 2017, 'Overview of ASDEX upgrade results', Nuclear Fusion, vol. 57, no. 10, 102015. https://doi.org/10.1088/1741-4326/aa64f6

Overview of ASDEX upgrade results. / Aguiam, D.; Aho-Mantila, Leena; Angioni, C.; Arden, N.; Arredondo Parra, R.; Asunta, O.; De Baar, M.; Balden, M.; Behler, K.; Bergmann, A.; Bernardo, J.; Bernert, M.; Beurskens, M.; Biancalani, A.; Bilato, R.; Birkenmeier, G.; Bobkov, V.; Bock, A.; Bogomolov, A.; Bolzonella, T.; Böswirth, B.; Bottereau, C.; Bottino, A.; Van Den Brand, H.; Brezinsek, S.; Brida, D.; Brochard, F.; Bruhn, C.; Buchanan, J.; Buhler, A.; Burckhart, A.; Cambon-Silva, D.; Camenen, Y.; Carvalho, P.; Carrasco, G.; Cazzaniga, C.; Carr, M.; Carralero, D.; Casali, L.; Castaldo, C.; Cavedon, M.; Challis, C.; Chankin, A.; Chapman, I.; Clairet, F.; Classen, I.; Coda, S.; Coelho, R.; Hakola, Antti H.; Salmi, Antti; Kallenbach, A. (Corresponding Author); ASDEX Upgrade Team.

In: Nuclear Fusion, Vol. 57, No. 10, 102015, 28.06.2017.

Research output: Contribution to journalReview ArticleScientificpeer-review

TY - JOUR

T1 - Overview of ASDEX upgrade results

AU - Aguiam, D.

AU - Aho-Mantila, Leena

AU - Angioni, C.

AU - Arden, N.

AU - Arredondo Parra, R.

AU - Asunta, O.

AU - De Baar, M.

AU - Balden, M.

AU - Behler, K.

AU - Bergmann, A.

AU - Bernardo, J.

AU - Bernert, M.

AU - Beurskens, M.

AU - Biancalani, A.

AU - Bilato, R.

AU - Birkenmeier, G.

AU - Bobkov, V.

AU - Bock, A.

AU - Bogomolov, A.

AU - Bolzonella, T.

AU - Böswirth, B.

AU - Bottereau, C.

AU - Bottino, A.

AU - Van Den Brand, H.

AU - Brezinsek, S.

AU - Brida, D.

AU - Brochard, F.

AU - Bruhn, C.

AU - Buchanan, J.

AU - Buhler, A.

AU - Burckhart, A.

AU - Cambon-Silva, D.

AU - Camenen, Y.

AU - Carvalho, P.

AU - Carrasco, G.

AU - Cazzaniga, C.

AU - Carr, M.

AU - Carralero, D.

AU - Casali, L.

AU - Castaldo, C.

AU - Cavedon, M.

AU - Challis, C.

AU - Chankin, A.

AU - Chapman, I.

AU - Clairet, F.

AU - Classen, I.

AU - Coda, S.

AU - Coelho, R.

AU - Hakola, Antti H.

AU - Salmi, Antti

AU - Kallenbach, A.

AU - ASDEX Upgrade Team

PY - 2017/6/28

Y1 - 2017/6/28

N2 - The ASDEX Upgrade (AUG) programme is directed towards physics input to critical elements of the ITER design and the preparation of ITER operation, as well as addressing physics issues for a future DEMO design. Since 2015, AUG is equipped with a new pair of 3-strap ICRF antennas, which were designed for a reduction of tungsten release during ICRF operation. As predicted, a factor two reduction on the ICRF-induced W plasma content could be achieved by the reduction of the sheath voltage at the antenna limiters via the compensation of the image currents of the central and side straps in the antenna frame. There are two main operational scenario lines in AUG. Experiments with low collisionality, which comprise current drive, ELM mitigation/suppression and fast ion physics, are mainly done with freshly boronized walls to reduce the tungsten influx at these high edge temperature conditions. Full ELM suppression and non-inductive operation up to a plasma current of Ip = 0.8 MA could be obtained at low plasma density. Plasma exhaust is studied under conditions of high neutral divertor pressure and separatrix electron density, where a fresh boronization is not required. Substantial progress could be achieved for the understanding of the confinement degradation by strong D puffing and the improvement with nitrogen or carbon seeding. Inward/outward shifts of the electron density profile relative to the temperature profile effect the edge stability via the pressure profile changes and lead to improved/decreased pedestal performance. Seeding and D gas puffing are found to effect the core fueling via changes in a region of high density on the high field side (HFSHD). The integration of all above mentioned operational scenarios will be feasible and naturally obtained in a large device where the edge is more opaque for neutrals and higher plasma temperatures provide a lower collisionality. The combination of exhaust control with pellet fueling has been successfully demonstrated. High divertor enrichment values of nitrogen EN ≥ 10 have been obtained during pellet injection, which is a prerequisite for the simultaneous achievement of good core plasma purity and high divertor radiation levels. Impurity accumulation observed in the all-metal AUG device caused by the strong neoclassical inward transport of tungsten in the pedestal is expected to be relieved by the higher neoclassical temperature screening in larger devices.

AB - The ASDEX Upgrade (AUG) programme is directed towards physics input to critical elements of the ITER design and the preparation of ITER operation, as well as addressing physics issues for a future DEMO design. Since 2015, AUG is equipped with a new pair of 3-strap ICRF antennas, which were designed for a reduction of tungsten release during ICRF operation. As predicted, a factor two reduction on the ICRF-induced W plasma content could be achieved by the reduction of the sheath voltage at the antenna limiters via the compensation of the image currents of the central and side straps in the antenna frame. There are two main operational scenario lines in AUG. Experiments with low collisionality, which comprise current drive, ELM mitigation/suppression and fast ion physics, are mainly done with freshly boronized walls to reduce the tungsten influx at these high edge temperature conditions. Full ELM suppression and non-inductive operation up to a plasma current of Ip = 0.8 MA could be obtained at low plasma density. Plasma exhaust is studied under conditions of high neutral divertor pressure and separatrix electron density, where a fresh boronization is not required. Substantial progress could be achieved for the understanding of the confinement degradation by strong D puffing and the improvement with nitrogen or carbon seeding. Inward/outward shifts of the electron density profile relative to the temperature profile effect the edge stability via the pressure profile changes and lead to improved/decreased pedestal performance. Seeding and D gas puffing are found to effect the core fueling via changes in a region of high density on the high field side (HFSHD). The integration of all above mentioned operational scenarios will be feasible and naturally obtained in a large device where the edge is more opaque for neutrals and higher plasma temperatures provide a lower collisionality. The combination of exhaust control with pellet fueling has been successfully demonstrated. High divertor enrichment values of nitrogen EN ≥ 10 have been obtained during pellet injection, which is a prerequisite for the simultaneous achievement of good core plasma purity and high divertor radiation levels. Impurity accumulation observed in the all-metal AUG device caused by the strong neoclassical inward transport of tungsten in the pedestal is expected to be relieved by the higher neoclassical temperature screening in larger devices.

KW - DEMO

KW - ITER

KW - nuclear fusion

KW - tokamak physics

UR - http://www.scopus.com/inward/record.url?scp=85028458117&partnerID=8YFLogxK

U2 - 10.1088/1741-4326/aa64f6

DO - 10.1088/1741-4326/aa64f6

M3 - Review Article

AN - SCOPUS:85028458117

VL - 57

JO - Nuclear Fusion

JF - Nuclear Fusion

SN - 0029-5515

IS - 10

M1 - 102015

ER -

Aguiam D, Aho-Mantila L, Angioni C, Arden N, Arredondo Parra R, Asunta O et al. Overview of ASDEX upgrade results. Nuclear Fusion. 2017 Jun 28;57(10). 102015. https://doi.org/10.1088/1741-4326/aa64f6