1
|
Krawczyk N, Czarnecka A, Ivanova-Stanik I, Zagórski R, Challis C, Frigione D, Giroud C, Graves J, Mantsinen MJ, Silburn S. Application of the VUV and the soft x-ray systems on JET for the study of intrinsic impurity behavior in neon seeded hybrid discharges. Rev Sci Instrum 2018; 89:10D131. [PMID: 30399789 DOI: 10.1063/1.5038930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 07/10/2018] [Indexed: 06/08/2023]
Abstract
This paper reports on impurity behavior in a set of hybrid discharges with Ne seeding-one of the techniques considered to reduce the power load on reactor walls. A series of experiments carried out with light gas injection on JET with the ITER-Like-Wall (ILW) suggests increased tungsten release and impurity accumulation [C. Challis et al., Europhysics Conference Abstracts 41F, 2.153 (2017)]. The presented method relies mainly on the measurements collected by vacuum-ultra-violet and soft X-ray (SXR) diagnostics including the "SOXMOS" spectrometer and the SXR camera system. Both diagnostics have some limitations. Consequently, only a combination of measurements from these systems is able to provide comprehensive information about high-Z [e.g., tungsten (W)] and mid-Z [nickel (Ni), iron (Fe), copper (Cu), and molybdenum (Mo)] impurities for their further quantitative diagnosis. Moreover, thanks to the large number of the SXR lines of sight, determination of a 2D radiation profile was also possible. Additionally, the experimental results were compared with numerical modeling based on integrated simulations with COREDIV. Detailed analysis confirmed that during seeding experiments, higher tungsten release is observed, which was also found in the past. Additionally, it was noticed that besides W, the contribution of molybdenum to SXR radiation was greater, which can be explained by the place of its origin.
Collapse
Affiliation(s)
- N Krawczyk
- Institute of Plasma Physics and Laser Microfusion, Hery 23, Warsaw 01-497, Poland
| | - A Czarnecka
- Institute of Plasma Physics and Laser Microfusion, Hery 23, Warsaw 01-497, Poland
| | - I Ivanova-Stanik
- Institute of Plasma Physics and Laser Microfusion, Hery 23, Warsaw 01-497, Poland
| | - R Zagórski
- Institute of Plasma Physics and Laser Microfusion, Hery 23, Warsaw 01-497, Poland
| | - C Challis
- CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - D Frigione
- Associazione EURO-ENEA, C.R.E. Frascati, Frascati, Italy
| | - C Giroud
- CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - J Graves
- Centre de Recherches en Physique des Plasmas, EPFL, Lausanne, Switzerland
| | | | - S Silburn
- CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| |
Collapse
|
2
|
García-Muñoz M, Fahrbach HU, Günter S, Igochine V, Mantsinen MJ, Maraschek M, Martin P, Piovesan P, Sassenberg K, Zohm H. Fast-ion losses due to high-frequency MHD perturbations in the ASDEX upgrade Tokamak. Phys Rev Lett 2008; 100:055005. [PMID: 18352383 DOI: 10.1103/physrevlett.100.055005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2007] [Indexed: 05/26/2023]
Abstract
Time-resolved energy and pitch angle measurements of fast-ion losses correlated in frequency and phase with high-frequency magnetohydrodynamic perturbations have been obtained for the first time in a magnetic fusion device and are presented here. A detailed analysis of fast-ion losses due to toroidal Alfvén eigenmodes has revealed the existence of a new core-localized magnetohydrodynamic perturbation, the sierpes mode. The sierpes mode is a non-Alfvénic instability which dominates the losses of fast ions in ion cyclotron resonance heated discharges, and it is named for its footprint in the spectrograms ("sierpes" means "snake" in Spanish). The sierpes mode has been reconstructed by means of highly resolved multichord soft-x-ray measurements.
Collapse
Affiliation(s)
- M García-Muñoz
- Max-Planck-Institut für Plasmaphysik, EURATOM Association Boltzmannstrasse 2, D-85748 Garching, Germany.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
3
|
Eriksson LG, Mueck A, Sauter O, Coda S, Mantsinen MJ, Mayoral ML, Westerhof E, Buttery RJ, McDonald D, Johnson T, Noterdaeme JM, De Vries P. Destabilization of fast-ion-induced long sawteeth by localized current drive in the JET tokamak. Phys Rev Lett 2004; 92:235004. [PMID: 15245165 DOI: 10.1103/physrevlett.92.235004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2003] [Indexed: 05/24/2023]
Abstract
In a tokamak fusion reactor the energetic alpha particles will transiently stabilize the magnetohydrodynamic activity causing sawtooth oscillations. The crash events terminating long sawtooth free periods can provide seed islands for neoclassical tearing modes [Phys. Rev. Lett. 88, 105001 (2002)]]. To shorten the sawtooth periods localized current drive near the q=1 surface is a possibility. This Letter provides the first experimental evidence for the effectiveness of this method in the different physics regime associated with fast-ion-induced long sawteeth on the JET tokamak.
Collapse
Affiliation(s)
- L-G Eriksson
- Association EURATOM-CEA, CEA/DSM/DRFC, CEA-Cadarache, F-13108 St. Paul lez Durance, France
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
4
|
Mantsinen MJ, Ingesson LC, Johnson T, Kiptily VG, Mayoral ML, Sharapov SE, Alper B, Bertalot L, Conroy S, Eriksson LG, Hellsten T, Noterdaeme JM, Popovichev S, Righi E, Tuccillo AA. Controlling the profile of ion-cyclotron-resonant ions in JET with the wave-induced pinch effect. Phys Rev Lett 2002; 89:115004. [PMID: 12225145 DOI: 10.1103/physrevlett.89.115004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2002] [Indexed: 05/23/2023]
Abstract
Experiments on the JET tokamak show that the wave-induced pinch in the presence of toroidally asymmetric waves can provide a tool for controlling the profile of ion-cyclotron-resonant 3He ions. Direct evidence for the wave-induced pinch has been obtained from the measured gamma-ray emission profiles. Concurrent differences in the excitation of Alfvén eigenmodes (AEs), sawtooth stabilization, electron temperatures, and fast-ion stored energies are observed. The measured location of the AEs and gamma-ray emission profiles are consistent with the fast-ion radial gradient providing the drive for AEs.
Collapse
Affiliation(s)
- M J Mantsinen
- Association Euratom-Tekes, Helsinki University of Technology, Finland
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Sauter O, Westerhof E, Mayoral ML, Alper B, Belo PA, Buttery RJ, Gondhalekar A, Hellsten T, Hender TC, Howell DF, Johnson T, Lamalle P, Mantsinen MJ, Milani F, Nave MFF, Nguyen F, Pecquet AL, Pinches SD, Podda S, Rapp J. Control of neoclassical tearing modes by sawtooth control. Phys Rev Lett 2002; 88:105001. [PMID: 11909362 DOI: 10.1103/physrevlett.88.105001] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2001] [Indexed: 05/23/2023]
Abstract
The onset of a neoclassical tearing mode (NTM) depends on the existence of a large enough seed island. It is shown in the Joint European Torus that NTMs can be readily destabilized by long-period sawteeth, such as obtained by sawtooth stabilization from ion-cyclotron heating or current drive. This has important implications for burning plasma scenarios, as alpha particles strongly stabilize the sawteeth. It is also shown that, by adding heating and current drive just outside the inversion radius, sawteeth are destabilized, resulting in shorter sawtooth periods and larger beta values being obtained without NTMs.
Collapse
Affiliation(s)
- O Sauter
- Centre de Recherches en Physique des Plasmas, Ass. EURATOM-Confédération Suisse, EPFL, 1015 Lausanne, Switzerland
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Mantsinen MJ, Mayoral ML, Kiptily VG, Sharapov SE, Alper B, Bickley A, de Baar M, Eriksson LG, Gondhalekar A, Hellsten T, Lawson K, Nguyen F, Noterdaeme JM, Righi E, Tuccillo AA, Zerbini M. Alpha-tail production with ion-cyclotron-resonance heating of 4He-beam ions in JET plasmas. Phys Rev Lett 2002; 88:105002. [PMID: 11909363 DOI: 10.1103/physrevlett.88.105002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2001] [Indexed: 05/23/2023]
Abstract
Third-harmonic ion-cyclotron-resonance heating of 4He-beam ions has produced for the first time on the JET tokamak high-energy populations of 4He ions to simulate 3.5 MeV fusion-born alpha (alpha) particles. Acceleration of 4He ions to the MeV energy range is confirmed by gamma-ray emission from the nuclear reaction 9Be(alpha,ngamma) 12C and excitation of Alfvén eigenmodes. Concomitant electron heating and sawtooth stabilization are observed. The scheme could be used in next-step tokamaks to gain information on trapped alpha particles and to test alpha diagnostics in the early nonactivated phase of operation.
Collapse
Affiliation(s)
- M J Mantsinen
- Helsinki University of Technology, Association Euratom-Tekes, Finland
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|