Overview of physics studies on ASDEX Upgrade

A. H. Hakola, T. Tala, et al., ASDEX Upgrade Team

Research output: Contribution to journalReview ArticleScientificpeer-review

3 Citations (Scopus)

Abstract

The ASDEX Upgrade (AUG) programme, jointly run with the EUROfusion MST1 task force, continues to significantly enhance the physics base of ITER and DEMO. Here, the full tungsten wall is a key asset for extrapolating to future devices. The high overall heating power, flexible heating mix and comprehensive diagnostic set allows studies ranging from mimicking the scrape-off-layer and divertor conditions of ITER and DEMO at high density to fully non-inductive operation (q 95 = 5.5, ) at low density. Higher installed electron cyclotron resonance heating power 6 MW, new diagnostics and improved analysis techniques have further enhanced the capabilities of AUG. Stable high-density H-modes with MW m-1 with fully detached strike-points have been demonstrated. The ballooning instability close to the separatrix has been identified as a potential cause leading to the H-mode density limit and is also found to play an important role for the access to small edge-localized modes (ELMs). Density limit disruptions have been successfully avoided using a path-oriented approach to disruption handling and progress has been made in understanding the dissipation and avoidance of runaway electron beams. ELM suppression with resonant magnetic perturbations is now routinely achieved reaching transiently . This gives new insight into the field penetration physics, in particular with respect to plasma flows. Modelling agrees well with plasma response measurements and a helically localised ballooning structure observed prior to the ELM is evidence for the changed edge stability due to the magnetic perturbations. The impact of 3D perturbations on heat load patterns and fast-ion losses have been further elaborated. Progress has also been made in understanding the ELM cycle itself. Here, new fast measurements of and E r allow for inter ELM transport analysis confirming that E r is dominated by the diamagnetic term even for fast timescales. New analysis techniques allow detailed comparison of the ELM crash and are in good agreement with nonlinear MHD modelling. The observation of accelerated ions during the ELM crash can be seen as evidence for the reconnection during the ELM. As type-I ELMs (even mitigated) are likely not a viable operational regime in DEMO studies of 'natural' no ELM regimes have been extended. Stable I-modes up to have been characterised using -feedback. Core physics has been advanced by more detailed characterisation of the turbulence with new measurements such as the eddy tilt angle - measured for the first time - or the cross-phase angle of and fluctuations. These new data put strong constraints on gyro-kinetic turbulence modelling. In addition, carefully executed studies in different main species (H, D and He) and with different heating mixes highlight the importance of the collisional energy exchange for interpreting energy confinement. A new regime with a hollow profile now gives access to regimes mimicking aspects of burning plasma conditions and lead to nonlinear interactions of energetic particle modes despite the sub-Alfvénic beam energy. This will help to validate the fast-ion codes for predicting ITER and DEMO.

Original languageEnglish
Article number112014
JournalNuclear Fusion
Volume59
Issue number11
DOIs
Publication statusPublished - 22 Jul 2019
MoE publication typeA2 Review article in a scientific journal

Fingerprint

physics
crashes
heating
perturbation
turbulence
ions
avoidance
energetic particles
magnetohydrodynamic flow
electron cyclotron resonance
hollow
tungsten
phase shift
penetration
dissipation
energy transfer
retarding
electron beams
vortices
heat

Keywords

  • DEMO
  • ITER
  • magnetic confinement
  • nuclear fusion
  • tokamak physics

Cite this

Hakola, A. H. ; Tala, T. ; et al. ; ASDEX Upgrade Team. / Overview of physics studies on ASDEX Upgrade. In: Nuclear Fusion. 2019 ; Vol. 59, No. 11.
@article{2237a1b8aa464eca994cede756713213,
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abstract = "The ASDEX Upgrade (AUG) programme, jointly run with the EUROfusion MST1 task force, continues to significantly enhance the physics base of ITER and DEMO. Here, the full tungsten wall is a key asset for extrapolating to future devices. The high overall heating power, flexible heating mix and comprehensive diagnostic set allows studies ranging from mimicking the scrape-off-layer and divertor conditions of ITER and DEMO at high density to fully non-inductive operation (q 95 = 5.5, ) at low density. Higher installed electron cyclotron resonance heating power 6 MW, new diagnostics and improved analysis techniques have further enhanced the capabilities of AUG. Stable high-density H-modes with MW m-1 with fully detached strike-points have been demonstrated. The ballooning instability close to the separatrix has been identified as a potential cause leading to the H-mode density limit and is also found to play an important role for the access to small edge-localized modes (ELMs). Density limit disruptions have been successfully avoided using a path-oriented approach to disruption handling and progress has been made in understanding the dissipation and avoidance of runaway electron beams. ELM suppression with resonant magnetic perturbations is now routinely achieved reaching transiently . This gives new insight into the field penetration physics, in particular with respect to plasma flows. Modelling agrees well with plasma response measurements and a helically localised ballooning structure observed prior to the ELM is evidence for the changed edge stability due to the magnetic perturbations. The impact of 3D perturbations on heat load patterns and fast-ion losses have been further elaborated. Progress has also been made in understanding the ELM cycle itself. Here, new fast measurements of and E r allow for inter ELM transport analysis confirming that E r is dominated by the diamagnetic term even for fast timescales. New analysis techniques allow detailed comparison of the ELM crash and are in good agreement with nonlinear MHD modelling. The observation of accelerated ions during the ELM crash can be seen as evidence for the reconnection during the ELM. As type-I ELMs (even mitigated) are likely not a viable operational regime in DEMO studies of 'natural' no ELM regimes have been extended. Stable I-modes up to have been characterised using -feedback. Core physics has been advanced by more detailed characterisation of the turbulence with new measurements such as the eddy tilt angle - measured for the first time - or the cross-phase angle of and fluctuations. These new data put strong constraints on gyro-kinetic turbulence modelling. In addition, carefully executed studies in different main species (H, D and He) and with different heating mixes highlight the importance of the collisional energy exchange for interpreting energy confinement. A new regime with a hollow profile now gives access to regimes mimicking aspects of burning plasma conditions and lead to nonlinear interactions of energetic particle modes despite the sub-Alfv{\'e}nic beam energy. This will help to validate the fast-ion codes for predicting ITER and DEMO.",
keywords = "DEMO, ITER, magnetic confinement, nuclear fusion, tokamak physics",
author = "H. Meyer and C. Angioni and Albert, {C. G.} and N. Arden and {Arredondo Parra}, R. and O. Asunta and {De Baar}, M. and M. Balden and V. Bandaru and K. Behler and A. Bergmann and J. Bernardo and M. Bernert and A. Biancalani and R. Bilato and G. Birkenmeier and Blanken, {T. C.} and V. Bobkov and A. Bock and T. Bolzonella and A. Bortolon and B. B{\"o}swirth and C. Bottereau and A. Bottino and {Van Den Brand}, H. and S. Brezinsek and D. Brida and F. Brochard and C. Bruhn and J. Buchanan and A. Buhler and A. Burckhart and Y. Camenen and D. Carlton and M. Carr and D. Carralero and C. Castaldo and M. Cavedon and C. Cazzaniga and S. Ceccuzzi and C. Challis and A. Chankin and S. Chapman and C. Cianfarani and F. Clairet and S. Coda and Hakola, {A. H.} and Y. Liu and A. Salmi and T. Tala and {et al.} and {ASDEX Upgrade Team}",
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Overview of physics studies on ASDEX Upgrade. / Hakola, A. H.; Tala, T.; et al.; ASDEX Upgrade Team.

In: Nuclear Fusion, Vol. 59, No. 11, 112014, 22.07.2019.

Research output: Contribution to journalReview ArticleScientificpeer-review

TY - JOUR

T1 - Overview of physics studies on ASDEX Upgrade

AU - Meyer, H.

AU - Angioni, C.

AU - Albert, C. G.

AU - Arden, N.

AU - Arredondo Parra, R.

AU - Asunta, O.

AU - De Baar, M.

AU - Balden, M.

AU - Bandaru, V.

AU - Behler, K.

AU - Bergmann, A.

AU - Bernardo, J.

AU - Bernert, M.

AU - Biancalani, A.

AU - Bilato, R.

AU - Birkenmeier, G.

AU - Blanken, T. C.

AU - Bobkov, V.

AU - Bock, A.

AU - Bolzonella, T.

AU - Bortolon, A.

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 - Camenen, Y.

AU - Carlton, D.

AU - Carr, M.

AU - Carralero, D.

AU - Castaldo, C.

AU - Cavedon, M.

AU - Cazzaniga, C.

AU - Ceccuzzi, S.

AU - Challis, C.

AU - Chankin, A.

AU - Chapman, S.

AU - Cianfarani, C.

AU - Clairet, F.

AU - Coda, S.

AU - Hakola, A. H.

AU - Liu, Y.

AU - Salmi, A.

AU - Tala, T.

AU - et al.,

AU - ASDEX Upgrade Team

PY - 2019/7/22

Y1 - 2019/7/22

N2 - The ASDEX Upgrade (AUG) programme, jointly run with the EUROfusion MST1 task force, continues to significantly enhance the physics base of ITER and DEMO. Here, the full tungsten wall is a key asset for extrapolating to future devices. The high overall heating power, flexible heating mix and comprehensive diagnostic set allows studies ranging from mimicking the scrape-off-layer and divertor conditions of ITER and DEMO at high density to fully non-inductive operation (q 95 = 5.5, ) at low density. Higher installed electron cyclotron resonance heating power 6 MW, new diagnostics and improved analysis techniques have further enhanced the capabilities of AUG. Stable high-density H-modes with MW m-1 with fully detached strike-points have been demonstrated. The ballooning instability close to the separatrix has been identified as a potential cause leading to the H-mode density limit and is also found to play an important role for the access to small edge-localized modes (ELMs). Density limit disruptions have been successfully avoided using a path-oriented approach to disruption handling and progress has been made in understanding the dissipation and avoidance of runaway electron beams. ELM suppression with resonant magnetic perturbations is now routinely achieved reaching transiently . This gives new insight into the field penetration physics, in particular with respect to plasma flows. Modelling agrees well with plasma response measurements and a helically localised ballooning structure observed prior to the ELM is evidence for the changed edge stability due to the magnetic perturbations. The impact of 3D perturbations on heat load patterns and fast-ion losses have been further elaborated. Progress has also been made in understanding the ELM cycle itself. Here, new fast measurements of and E r allow for inter ELM transport analysis confirming that E r is dominated by the diamagnetic term even for fast timescales. New analysis techniques allow detailed comparison of the ELM crash and are in good agreement with nonlinear MHD modelling. The observation of accelerated ions during the ELM crash can be seen as evidence for the reconnection during the ELM. As type-I ELMs (even mitigated) are likely not a viable operational regime in DEMO studies of 'natural' no ELM regimes have been extended. Stable I-modes up to have been characterised using -feedback. Core physics has been advanced by more detailed characterisation of the turbulence with new measurements such as the eddy tilt angle - measured for the first time - or the cross-phase angle of and fluctuations. These new data put strong constraints on gyro-kinetic turbulence modelling. In addition, carefully executed studies in different main species (H, D and He) and with different heating mixes highlight the importance of the collisional energy exchange for interpreting energy confinement. A new regime with a hollow profile now gives access to regimes mimicking aspects of burning plasma conditions and lead to nonlinear interactions of energetic particle modes despite the sub-Alfvénic beam energy. This will help to validate the fast-ion codes for predicting ITER and DEMO.

AB - The ASDEX Upgrade (AUG) programme, jointly run with the EUROfusion MST1 task force, continues to significantly enhance the physics base of ITER and DEMO. Here, the full tungsten wall is a key asset for extrapolating to future devices. The high overall heating power, flexible heating mix and comprehensive diagnostic set allows studies ranging from mimicking the scrape-off-layer and divertor conditions of ITER and DEMO at high density to fully non-inductive operation (q 95 = 5.5, ) at low density. Higher installed electron cyclotron resonance heating power 6 MW, new diagnostics and improved analysis techniques have further enhanced the capabilities of AUG. Stable high-density H-modes with MW m-1 with fully detached strike-points have been demonstrated. The ballooning instability close to the separatrix has been identified as a potential cause leading to the H-mode density limit and is also found to play an important role for the access to small edge-localized modes (ELMs). Density limit disruptions have been successfully avoided using a path-oriented approach to disruption handling and progress has been made in understanding the dissipation and avoidance of runaway electron beams. ELM suppression with resonant magnetic perturbations is now routinely achieved reaching transiently . This gives new insight into the field penetration physics, in particular with respect to plasma flows. Modelling agrees well with plasma response measurements and a helically localised ballooning structure observed prior to the ELM is evidence for the changed edge stability due to the magnetic perturbations. The impact of 3D perturbations on heat load patterns and fast-ion losses have been further elaborated. Progress has also been made in understanding the ELM cycle itself. Here, new fast measurements of and E r allow for inter ELM transport analysis confirming that E r is dominated by the diamagnetic term even for fast timescales. New analysis techniques allow detailed comparison of the ELM crash and are in good agreement with nonlinear MHD modelling. The observation of accelerated ions during the ELM crash can be seen as evidence for the reconnection during the ELM. As type-I ELMs (even mitigated) are likely not a viable operational regime in DEMO studies of 'natural' no ELM regimes have been extended. Stable I-modes up to have been characterised using -feedback. Core physics has been advanced by more detailed characterisation of the turbulence with new measurements such as the eddy tilt angle - measured for the first time - or the cross-phase angle of and fluctuations. These new data put strong constraints on gyro-kinetic turbulence modelling. In addition, carefully executed studies in different main species (H, D and He) and with different heating mixes highlight the importance of the collisional energy exchange for interpreting energy confinement. A new regime with a hollow profile now gives access to regimes mimicking aspects of burning plasma conditions and lead to nonlinear interactions of energetic particle modes despite the sub-Alfvénic beam energy. This will help to validate the fast-ion codes for predicting ITER and DEMO.

KW - DEMO

KW - ITER

KW - magnetic confinement

KW - nuclear fusion

KW - tokamak physics

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