A large scale program to develop a conceptual design for a demonstration fusion power plant (DEMO) has been initiated in Europe. Central elements are the baseline design points, which are developed by system codes. The assessment of the credibility of these design points is often hampered by missing information. The main physics and technology content of the central European system codes have been published (Kovari et al 2014 Fusion Eng. Des . 89 3054–69, 2016 Fusion Eng. Des . 104 9–20, Reux et al 2015 Nucl. Fusion 55 073011). In addition, this publication discusses key input parameters for the pulsed and conservative design option...).

VL - 57 UR - http://www.euro-fusionscipub.org/wp-content/uploads/WPPMIPR16_16121_submitted.pdf IS - 1 U1 -FP

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U3 - FP120 U5 - 6b859a47ed93fe9914481453756cfbce ER - TY - JOUR T1 - Overview of progress in European medium sized tokamaks towards an integrated plasma-edge/wall solution JF - Nuclear Fusion Y1 - 2017 A1 - Meyer, H. A1 - Eich, T. A1 - Citrin, J. A1 - Classen, I. A1 - Hogeweij, D. A1 - Jaulmes, F. A1 - Kappatou, A. A1 - van den Brand, H. A1 - Vanovac, B. A1 - Vijvers, W. A. J. A1 - Westerhof, E. A1 - et al. AB - Integrating the plasma core performance with an edge and scrape-off layer (SOL) that leads to tolerable heat and particle loads on the wall is a major challenge. The new European medium size tokamak task force (EU-MST) coordinates research on ASDEX Upgrade (AUG), MAST and TCV. This multi-machine approach within EU-MST, covering a wide parameter range, is instrumental to progress in the field, as ITER and DEMO core/pedestal and SOL parameters are not achievable simultaneously in present day devices. A two prong approach is adopted. On the one hand, scenarios with tolerable transient heat and particle loads, including active edge localised mode (ELM) control are developed. On the other hand, divertor solutions including advanced magnetic configurations are studied. Considerable progress has been made on both approaches, in particular in the fields of: ELM control with resonant magnetic perturbations (RMP), small ELM regimes, detachment onset and control, as well as filamentary scrape-off-layer transport. For example full ELM suppression has now been achieved on AUG at low collisionality with n = 2 RMP maintaining good confinement H H(98,y2) =approx 0.95. Advances have been made with respect to detachment onset and control. Studies in advanced divertor configurations (Snowflake, Super-X and X-point target divertor) shed new light on SOL physics. Cross field filamentary transport has been characterised in a wide parameter regime on AUG, MAST and TCV progressing the theoretical and experimental understanding crucial for predicting first wall loads in ITER and DEMO. Conditions in the SOL also play a crucial role for ELM stability and access to small ELM regimes. VL - 57 IS - 10 U1 - FP U2 - PEPD U5 - f781e58d912e0c330cdf9b05c806267b ER - TY - JOUR T1 - Plasma–wall interaction studies within the EUROfusion consortium: progress on plasma-facing components development and qualification JF - Nuclear Fusion Y1 - 2017 A1 - Brezinsek, S. A1 - Coenen, J. W. A1 - Schwartz-Selinger, T. A1 - Schmid, K. A1 - Kirschner, A. A1 - Hakola, A. A1 - Tabares, F. L. A1 - van der Meiden, H. J. A1 - Mayoral, M. A1 - Reinhart, M. A1 - Tsitrone, E. A1 - Vernimmen, J. W. M. A1 - Morgan, T. W. A1 - Ahlgren, T. A1 - Aints, M. A1 - Airila, M. A1 - Almaviva, S. A1 - Alves, E. A1 - Angot, T. A1 - Anita, V. A1 - R. Arredondo Parra A1 - Aumayr, F. A1 - Balden, M. A1 - Bauer, J. A1 - Ben Yaala, M. A1 - Berger, B. M. A1 - Bisson, R. A1 - Björkas, C. A1 - Bogdanovic Radovic, I. A1 - Borodin, D. A1 - Bucalossi, J. A1 - Butikova, J. A1 - Butoi, B. A1 - Cadez, I. A1 - Caniello, R. A1 - Caneve, L. A1 - Cartry, G. A1 - Catarino, N. A1 - Čekada, M. A1 - Ciraolo, G. A1 - Ciupinski, L. A1 - Colao, F. A1 - Corre, Y. A1 - Costin, C. A1 - Craciunescu, T. A1 - Cremona, A. A1 - de Angeli, M. A1 - de Castro, A. A1 - Dejarnac, R. A1 - Dellasega, D. A1 - Dinca, P. A1 - Dittmar, T. A1 - Dobrea, C. A1 - Hansen, P. A1 - Drenik, A. A1 - Eich, T. A1 - Elgeti, S. A1 - Falie, D. A1 - Fedorczak, N. A1 - Ferro, Y. A1 - Fornal, T. A1 - Fortuna, E. A1 - Gao, L. A1 - Gasior, P. A1 - Gherendi, M. A1 - Ghezzi, F. A1 - Gosar, Z. A1 - Greuner, H. A1 - Grigore, E. A1 - Grisolia, C. A1 - Groth, M. A1 - Gruca, M. A1 - Grzonka, J. A1 - Gunn, J. P. A1 - Hassouni, K. A1 - Heinola, K. A1 - Höschen, T. A1 - Huber, S. A1 - Jacob, W. A1 - Jepu, I. A1 - Jiang, X. A1 - Jogi, I. A1 - Kaiser, A. A1 - Karhunen, J. A1 - Kelemen, M. A1 - Köppen, M. A1 - Koslowski, H. R. A1 - Kreter, A. A1 - Kubkowska, M. A1 - Laan, M. A1 - Laguardia, L. A1 - Lahtinen, A. A1 - Lasa, A. A1 - Lazic, V. A1 - Lemahieu, N. A1 - Likonen, J. A1 - Linke, J. A1 - Litnovsky, A. A1 - Linsmeier, C. A1 - Loewenhoff, T. A1 - Lungu, C. A1 - Lungu, M. A1 - Maddaluno, G. A1 - Maier, H. A1 - Makkonen, T. A1 - Manhard, A. A1 - Marandet, Y. A1 - Markelj, S. A1 - Marot, L. A1 - Martin, C. A1 - Martin-Rojo, A. B. A1 - Martynova, Y. A1 - Mateus, R. A1 - Matveev, D. A1 - Mayer, M. A1 - Meisl, G. A1 - Mellet, N. A1 - Michau, A. A1 - Miettunen, J. A1 - Möller, S. A1 - Mougenot, J. A1 - Mozetic, M. A1 - Nemanič, V. A1 - Neu, R. A1 - Nordlund, K. A1 - Oberkofler, M. A1 - Oyarzabal, E. A1 - Panjan, M. A1 - Pardanaud, C. A1 - Paris, P. A1 - Passoni, M. A1 - Pegourie, B. A1 - Pelicon, P. A1 - Petersson, P. A1 - Piip, K. A1 - Pintsuk, G. A1 - Pompilian, G. O. A1 - Popa, G. A1 - Porosnicu, C. A1 - Primc, G. A1 - Probst, M. A1 - Räisänen, J. A1 - Rasinski, M. A1 - Ratynskaia, S. A1 - Reiser, D. A1 - Ricci, D. A1 - Richou, M. A1 - Riesch, J. A1 - Riva, G. A1 - Rosinski, M. A1 - Roubin, P. A1 - Rubel, M. A1 - Ruset, C. A1 - Safi, E. A1 - Sergienko, G. A1 - Siketic, Z. A1 - Sima, A. A1 - Spilker, B. A1 - Stadlmayr, R. A1 - Steudel, I. A1 - Ström, P. A1 - Tadic, T. A1 - Tafalla, D. A1 - Tale, I. A1 - Terentyev, D. A1 - Terra, A. A1 - Tiron, V. A1 - Tiseanu, I. A1 - Tolias, P. A1 - Tskhakaya, D. A1 - Uccello, A. A1 - Unterberg, B. A1 - Uytdenhoven, I. A1 - Vassallo, E. A1 - Vavpetic, P. A1 - Veis, P. A1 - Velicu, I. L. A1 - Voitkans, A. A1 - von Toussaint, U. A1 - Weckmann, A. A1 - Wirtz, M. A1 - Zaloznik, A. A1 - Zaplotnik, R. A1 - WP PFC contributors AB - The provision of a particle and power exhaust solution which is compatible with first-wall components and edge-plasma conditions is a key area of present-day fusion research and mandatory for a successful operation of ITER and DEMO. The work package plasma-facing components (WP PFC) within the European fusion programme complements with laboratory experiments, i.e. in linear plasma devices, electron and ion beam loading facilities, the studies performed in toroidally confined magnetic devices, such as JET, ASDEX Upgrade, WEST etc. The connection of both groups is done via common physics and engineering studies, including the qualification and specification of plasma-facing components, and by modelling codes that simulate edge-plasma conditions and the plasma–material interaction as well as the study of fundamental processes. WP PFC addresses these critical points in order to ensure reliable and efficient use of conventional, solid PFCs in ITER (Be and W) and DEMO (W and steel) with respect to heat-load capabilities (transient and steady-state heat and particle loads), lifetime estimates (erosion, material mixing and surface morphology), and safety aspects (fuel retention, fuel removal, material migration and dust formation) particularly for quasi-steady-state conditions. Alternative scenarios and concepts (liquid Sn or Li as PFCs) for DEMO are developed and tested in the event that the conventional solution turns out to not be functional. Here, we present an overview of the activities with an emphasis on a few key results: (i) the observed synergistic effects in particle and heat loading of ITER-grade W with the available set of exposition devices on material properties such as roughness, ductility and microstructure; (ii) the progress in understanding of fuel retention, diffusion and outgassing in different W-based materials, including the impact of damage and impurities like N; and (iii), the preferential sputtering of Fe in EUROFER steel providing an in situ W surface and a potential first-wall solution for DEMO. VL - 57 IS - 11 U1 - PSI U2 - PMI U5 - 4f90e0cf51291a6cb8b6e575c66f5043 ER - TY - JOUR T1 - European roadmap to the realization of fusion energy: Mission for solution on heat-exhaust systems JF - Fusion Engineering and Design Y1 - 2015 A1 - Turnyanskiy, M. A1 - Neu, R. A1 - Albanese, R. A1 - Ambrosino, R. A1 - Bachmann, C. A1 - Brezinsek, S. A1 - Donne, A. J. H. A1 - Eich, T. A1 - Falchetto, G. A1 - G Federici A1 - Kalupin, D. A1 - X. Litaudon A1 - Mayoral, M. A1 - McDonald, D. C. A1 - Reimerdes, H. A1 - Romanelli, F. A1 - Wenninger, R. A1 - You, J. H. AB - Horizon 2020 is the largest EU Research and Innovation programme to date. The European fusion research programme for Horizon 2020 is outlined in the “Roadmap to the realization of fusion energy” and published in 2012 [1]. As part of it, the European Fusion Consortium (EUROfusion) has been established and will be responsible for implementing this roadmap through its members. The European fusion roadmap sets out a strategy for a collaboration to achieve the goal of generating fusion electricity by 2050. It is based on a goal-oriented approach with eight different missions including the development of heat-exhaust systems which must be capable of withstanding the large heat and particle fluxes of a fusion power plant (FPP). A summary of the main aims of the mission for a solution on heat-exhaust systems and the EUROfusion consortium strategy to set up an efficient Work Breakdown Structure and the collaborative efforts to address these challenges will be presented. VL - 96–97 N1 - Proceedings of the 28th Symposium On Fusion Technology (SOFT-28) U1 - FP U2 - TP U5 - b61995676469b29270465d18dfd8e778 ER - TY - JOUR T1 - Global and pedestal confinement in JET with a Be/W metallic wall JF - Nuclear Fusion Y1 - 2014 A1 - Beurskens, M. N. A. A1 - Frassinetti, L. A1 - Challis, C. A1 - Giroud, C. A1 - Saarelma, S. A1 - Alper, B. A1 - Angioni, C. A1 - P. Bilkova A1 - Bourdelle, C. A1 - Brezinsek, S. A1 - Buratti, P. A1 - Calabro, G. A1 - Eich, T. A1 - Flanagan, J. A1 - Giovannozzi, E. A1 - Groth, M. A1 - Hobirk, J. A1 - Joffrin, E. A1 - Leyland, M. J. A1 - Lomas, P. A1 - de la Luna, E. A1 - Kempenaars, M. A1 - Maddison, G. A1 - Maggi, C. A1 - Mantica, P. A1 - Maslov, M. A1 - Matthews, G. A1 - M-L Mayoral A1 - Neu, R. A1 - Nunes, I. A1 - Osborne, T. A1 - Rimini, F. A1 - Scannell, R. A1 - Solano, E. R. A1 - Snyder, P. B. A1 - Voitsekhovitch, I. A1 - de Vries, P. C. A1 - JET-EFDA Contributors AB - Type I ELMy H-mode operation in JET with the ITER-like Be/W wall (JET-ILW) generally occurs at lower pedestal pressures compared to those with the full carbon wall (JET-C). The pedestal density is similar but the pedestal temperature where type I ELMs occur is reduced and below to the so-called critical type I-type III transition temperature reported in JET-C experiments. Furthermore, the confinement factor H 98( y ,2) in type I ELMy H-mode baseline plasmas is generally lower in JET-ILW compared to JET-C at low power fractions P loss / P thr,08 < 2 (where P loss is ( P in − d W /d t ), and P thr,08 the LH power threshold from Martin et al 2008 ( J. Phys. Conf. Ser. 123 [http://dx.doi.org/10.1088/1742-6596/123/1/012033] 012033 )). Higher power fractions have thus far not been achieved in the baseline plasmas. At P loss / P thr,08 > 2, the confinement in JET-ILW hybrid plasmas is similar to that in JET-C. A reduction in pedestal pressure is the main reason for the reduced confinement in JET-ILW baseline ELMy H-mode plasmas where typically H 98( y ,2) = 0.8 is obtained, compared to H 98( y ,2) = 1.0 in JET-C. In JET-ILW hybrid plasmas a similarly reduced pedestal pressure is compensated by an increased peaking of the core pressure profile resulting in H 98( y ,2) ⩽ 1.25. The pedestal stability has significantly changed in high triangularity baseline plasmas where the confinement loss is also most apparent. Applying the same stability analysis for JET-C and JET-ILW, the measured pedestal in JET-ILW is stable with respect to the calculated peeling ballooning stability limit and the ELM collapse time has increased to 2 ms from typically 200 µ s in JET-C. This indicates that changes in the pedestal stability may have contributed to the reduced pedestal confinement in JET-ILW plasmas. A comparison of EPED1 pedestal pressure prediction with JET-ILW experimental data in over 500 JET-C and JET-ILW baseline and hybrid plasmas shows a good agreement with 0.8 < (measured p ped )/(predicted p ped,EPED ) < 1.2, but that the role of triangularity is generally weaker in the JET-ILW experimental data than in the model predictions. VL - 54 UR - http://www.iop.org/Jet/article?EFDP12051&EFDP12058 IS - 4 U1 - FP U2 - PDG U5 - 0db46cb7db189d845dec2f404c29ef68 ER - TY - JOUR T1 - Contrasting H-mode behaviour with deuterium fuelling and nitrogen seeding in the all-carbon and metallic versions of JET JF - Nuclear Fusion Y1 - 2014 A1 - G. P. Maddison A1 - Giroud, C. A1 - Alper, B. A1 - Arnoux, G. A1 - Balboa, I. A1 - Beurskens, M. N. A. A1 - Boboc, A. A1 - Brezinsek, S. A1 - Brix, M. A1 - Clever, M. A1 - Coelho, R. A1 - Coenen, J. W. A1 - Coffey, I. A1 - da Silva Aresta Belo, P. A1 - Devaux, S. A1 - Devynck, P. A1 - Eich, T. A1 - Felton, R. C. A1 - Flanagan, J. A1 - Frassinetti, L. A1 - Garzotti, L. A1 - Groth, M. A1 - Jachmich, S. A1 - Jarvinen, A. A1 - Joffrin, E. A1 - Kempenaars, M. A1 - Kruezi, U. A1 - Lawson, K. D. A1 - Lehnen, M. A1 - Leyland, M. J. A1 - Liu, Y. A1 - Lomas, P. J. A1 - Lowry, C. G. A1 - Marsen, S. A1 - Matthews, G. F. A1 - McCormick, G. K. A1 - Meigs, A. G. A1 - Morris, A. W. A1 - Neu, R. A1 - Nunes, I. M. A1 - Oberkofler, M. A1 - Rimini, F. G. A1 - Saarelma, S. A1 - Sieglin, B. A1 - Sips, A.C.C. A1 - Sirinelli, A. A1 - Stamp, M. F. A1 - G. J. van Rooij A1 - Ward, D. J. A1 - Wischmeier, M. A1 - JET-EFDA Contributors AB - The former all-carbon wall on JET has been replaced with beryllium in the main torus and tungsten in the divertor to mimic the surface materials envisaged for ITER. Comparisons are presented between type I H-mode characteristics in each design by examining respective scans over deuterium fuelling and impurity seeding, required to ameliorate exhaust loads both in JET at full capability and in ITER. Attention is focused upon a common high-triangularity, single-null divertor configuration at 2.5 MA, q 95 ≈ 3.5 yielding the most robust all-C performance. Contrasting results between the alternative linings are found firstly in unseeded plasmas, for which purity is improved and intrinsic radiation reduced in the ITER-like wall (ILW) but normalized energy confinement is ≈30% lower than in all-C counterparts, owing to a commensurately lower (electron) pedestal temperature. Divertor recycling is also radically altered, with slower, inboard/outboard asymmetric transients at ELMs and spontaneous oscillations in between them. Secondly, nitrogen seeding elicits opposite responses in the ILW to all-C experience, tending to raise plasma density, reduce ELM frequency, and above all to recover (electron) pedestal pressure, hence global confinement, almost back to previous levels. A hitherto unrecognized role of light impurities in pedestal stability and dynamics is consequently suggested. Thirdly, while heat loads on the divertor outboard target between ELMs are successfully reduced in proportion to the radiative cooling and ELM frequency effects of N in both wall environments, more surprisingly, average power ejected by ELMs also declines in the same proportion for the ILW. Detachment between transients is simultaneously promoted. Finally, inter-ELM W sources in the ILW divertor tend to fall with N input, although core accumulation possibly due to increased particle confinement still leads to significantly less steady conditions than in all-C plasmas. This limitation of ILW H-modes so far will be readdressed in future campaigns to continue progress towards a fully integrated scenario suitable for D T experiments on JET and for ‘baseline’ operation on ITER. The diverse changes in behaviour between all-C and ILW contexts demonstrate essentially the strong impact which boundary conditions and intrinsic impurities can have on tokamak-plasma states. VL - 54 UR - http://www.iop.org/Jet/article?EFDP13011&EFDP13018 U1 - MaSF U2 - MaSF-E U5 - f14366e6d4de5a085217627f6a96a779 ER - TY - JOUR T1 - Power handling of the JET ITER-like wall JF - Physica Scripta Y1 - 2014 A1 - Arnoux, G. A1 - Balboa, I. A1 - Clever, M. A1 - Devaux, S. A1 - P. de Vries A1 - Eich, T. A1 - M Firdaouss A1 - Jachmich, S. A1 - Lehnen, M. A1 - Lomas, P. J. A1 - Matthews, G. F. A1 - Mertens, P. A1 - Nunes, I. A1 - Riccardo, V. A1 - Ruset, C. A1 - Sieglin, B. A1 - D F Valcárcel A1 - J Wilson A1 - Zastrow, K. D. A1 - JET-EFDA Contributors AB - The ITER-like wall (ILW) at JET provides a unique opportunity to study the combination of material (beryllium and tungsten) that will be used for the plasma facing components (PFCs) in ITER. Both the limiters (Be) and divertor (CFC W coated and bulk W) have been designed to maximize their power handling capability. During the last experimental campaign (October 2010–July 2011) this capability has been assessed and even challenged in the case of the Be wall. The Be limiters' power handling capability (19 MW m −2 s −1/2 ), predicted with a simple model, has been proven to be robust by the experiments despite an unexpected power load pattern. This capability has been pushed to its limit leading to Be melt events, which revealed that the power load is toroidally asymmetric. The protection system of the ILW did not prevent melt events mainly because the protection strategy relies on the assumption that the power load is toroidally symmetric. The bulk W divertor target performed as predicted. Operations were constrained by: (i) an energy load limit (60 MJ m −2 ); (ii) the limited number of cycles of the surface temperature above 1200 °C in order to prevent thermal fatigue. This latter limit has been exceeded about 300 times and no signs of damage or thermal fatigue have been observed by the photogrammetric survey. VL - 2014 UR - http://stacks.iop.org/1402-4896/2014/i=T159/a=014009 IS - T159 U1 - FP U2 - PDG U5 - bf3504031bc533d74bc942444f6b73b4 ER - TY - JOUR T1 - Confinement and edge studies towards low ρ* and ν* at JET JF - Nuclear Fusion Y1 - 2013 A1 - Nunes, I. A1 - Lomas, P. J. A1 - McDonald, D. C. A1 - Saibene, G. A1 - Sartori, R. A1 - Voitsekhovitch, I. A1 - Beurskens, M. A1 - Arnoux, G. A1 - Boboc, A. A1 - Eich, T. A1 - Giroud, C. A1 - S. Heureux A1 - de la Luna, E. A1 - Maddison, G. A1 - Sips, A.C.C. A1 - Thomsen, H. A1 - Versloot, T. W. A1 - JET-EFDA Contributors AB -The size and capability of JET to reach high plasma current and field enables a study of the plasma behaviour at ion Larmor radius and collisionality values approaching those of ITER. In this paper such study is presented. The achievement of stationary type I ELMy H-modes at high current proved to be quite challenging. As the plasma current was increased, it became more difficult to achieve stationary conditions. Nevertheless, it was possible to achieve stable operation at high plasma current (up to 4.5 MA) and low q 95 (2.65–3) at JET. One of the main reasons to revisit the high plasma current experiments done in 1997 is the higher power available and the improvement of the pedestal diagnostics. Indeed, compared with previous results, higher stored energy was achieved but confinement was still degraded. The causes of this confinement degradation are discussed in the paper.

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U5 - d22634a34b4738abab689b664e7b3ea9 ER - TY - JOUR T1 - Impact of carbon and tungsten as divertor materials on the scrape-off layer conditions in JET JF - Nuclear Fusion Y1 - 2013 A1 - Groth, M. A1 - Brezinsek, S. A1 - Belo, P. A1 - Beurskens, M. N. A. A1 - Brix, M. A1 - Clever, M. A1 - Coenen, J. W. A1 - Corrigan, C. A1 - Eich, T. A1 - Flanagan, J. A1 - Guillemaut, C. A1 - Giroud, C. A1 - Harting, D. A1 - Huber, A. A1 - Jachmich, S. A1 - Kruezi, U. A1 - Lawson, K. D. A1 - Lehnen, M. A1 - Lowry, C. A1 - Maggi, C. F. A1 - Marsen, S. A1 - Meigs, A. G. A1 - Pitts, R.A. A1 - Sergienko, G. A1 - Sieglin, B. A1 - Silva, C. A1 - Sirinelli, A. A1 - Stamp, M. F. A1 - G. J. van Rooij A1 - Wiesen, S. A1 - JET-EFDA Contributors AB -The impact of carbon and beryllium/tungsten as plasma-facing components on plasma radiation, divertor power and particle fluxes, and plasma and neutral conditions in the divertors has been assessed in JET both experimentally and by edge fluid code simulations for plasmas in low-confinement mode. In high-recycling conditions the studies show a 30% reduction in total radiation in the scrape-off (SOL) layer when replacing carbon (JET-C) with beryllium in the main chamber and tungsten in the divertor (JET-ILW). Correspondingly, at the low-field side (LFS) divertor plate a two-fold increase in power conducted to the plate and a two-fold increase in electron temperature at the strike point were measured. In low-recycling conditions the SOL was found to be nearly identical for both materials' configurations. Saturation and rollover of the ion currents to both low- and high-field side (HFS) plates was measured to occur at 30% higher upstream densities and radiated power fraction in JET-ILW. Past saturation, it was possible to reduce the ion currents to the LFS targets by a factor of 2 and to continue operating in stable, detached conditions in JET-ILW; in JET-C the reduction was limited to 50%. These observations are in qualitative agreement with predictions from the fluid edge code package EDGE2D/EIRENE, for which a 30% reduction of the total radiated power is also yielded when switching from C to Be/W. For matching upstream parameters the magnitude of predicted radiation is, however, 50% to 100% lower than measured, independent of the materials' configuration. Inclusion of deuterium molecules and molecular ions, and temperature and density dependent rates in EIRENE reproduced the experimentally observed rollover of the ion current to the LFS plate, via reducing the electron temperature at the plate.

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U5 - e6475d91c3e0170859510179c3cf0128 ER - TY - JOUR T1 - Overview of ASDEX Upgrade results JF - Nuclear Fusion Y1 - 2013 A1 - Stroth, U. A1 - Adamek, J. A1 - Aho-Mantila, L. A1 - Akaslompolo, S. A1 - Amdor, C. A1 - Angioni, C. A1 - Balden, M. A1 - Bardin, S. A1 - L. Barrera Orte A1 - Behler, K. A1 - Belonohy, E. A1 - Bergmann, A. A1 - Bernert, M. A1 - Bilato, R. A1 - Birkenmeier, G. A1 - Bobkov, V. A1 - Boom, J. A1 - Bottereau, C. A1 - Bottino, A. A1 - Braun, F. A1 - Brezinsek, S. A1 - Brochard, T. A1 - M. Brüdgam A1 - Buhler, A. A1 - Burckhart, A. A1 - Casson, F. J. A1 - Chankin, A. A1 - Chapman, I. A1 - Clairet, F. A1 - Classen, I.G.J. A1 - Coenen, J. W. A1 - Conway, G. D. A1 - Coster, D. P. A1 - Curran, D. A1 - da Silva, F. A1 - P. de Marné A1 - D'Inca, R. A1 - Douai, D. A1 - Drube, R. A1 - Dunne, M. A1 - Dux, R. A1 - Eich, T. A1 - Eixenberger, H. A1 - Endstrasser, N. A1 - Engelhardt, K. A1 - Esposito, B. A1 - Fable, E. A1 - Fischer, R. A1 - H. Fünfgelder A1 - Fuchs, J. C. A1 - K. Gál A1 - M. García Muñoz A1 - Geiger, B. A1 - Giannone, L. A1 - T. Görler A1 - da Graca, S. A1 - Greuner, H. A1 - Gruber, O. A1 - Gude, A. A1 - Guimarais, L. A1 - S. Günter A1 - Haas, G. A1 - Hakola, A. H. A1 - Hangan, D. A1 - Happel, T. A1 - T. Härtl A1 - Hauff, T. A1 - Heinemann, B. A1 - Herrmann, A. A1 - Hobirk, J. A1 - H. Höhnle A1 - M. Hölzl A1 - Hopf, C. A1 - Houben, A. A1 - Igochine, V. A1 - Ionita, C. A1 - Janzer, A. A1 - Jenko, F. A1 - Kantor, M. A1 - C.-P. Käsemann A1 - Kallenbach, A. A1 - S. Kálvin A1 - Kantor, M. A1 - Kappatou, A. A1 - Kardaun, O. A1 - Kasparek, W. A1 - Kaufmann, M. A1 - Kirk, A. A1 - H.-J. Klingshirn A1 - Kocan, M. A1 - Kocsis, G. A1 - Konz, C. A1 - Koslowski, R. A1 - Krieger, K. A1 - Kubic, M. A1 - Kurki-Suonio, T. A1 - Kurzan, B. A1 - Lackner, K. A1 - Lang, P. T. A1 - Lauber, P. A1 - Laux, M. A1 - Lazaros, A. A1 - Leipold, F. A1 - Leuterer, F. A1 - Lindig, S. A1 - Lisgo, S. A1 - Lohs, A. A1 - Lunt, T. A1 - Maier, H. A1 - Makkonen, T. A1 - Mank, K. A1 - M.-E. Manso A1 - Maraschek, M. A1 - Mayer, M. A1 - McCarthy, P. J. A1 - McDermott, R. A1 - Mehlmann, F. A1 - Meister, H. A1 - Menchero, L. A1 - Meo, F. A1 - Merkel, P. A1 - Merkel, R. A1 - Mertens, V. A1 - Merz, F. A1 - Mlynek, A. A1 - Monaco, F. A1 - Müller, S. A1 - H.W. Müller A1 - M. Münich A1 - Neu, G. A1 - Neu, R. A1 - Neuwirth, D. A1 - Nocente, M. A1 - Nold, B. A1 - Noterdaeme, J. M. A1 - Pautasso, G. A1 - Pereverzev, G. A1 - B. Plöckl A1 - Podoba, Y. A1 - Pompon, F. A1 - Poli, E. A1 - Polozhiy, K. A1 - Potzel, S. A1 - M. J. Pueschel A1 - Putterich, T. A1 - Rathgeber, S. K. A1 - Raupp, G. A1 - Reich, M. A1 - Reimold, F. A1 - Ribeiro, T. A1 - Riedl, R. A1 - Rohde, V. A1 - G. J. van Rooij A1 - Roth, J. A1 - Rott, M. A1 - Ryter, F. A1 - Salewski, M. A1 - Santos, J. A1 - Sauter, P. A1 - Scarabosio, A. A1 - Schall, G. A1 - Schmid, K. A1 - Schneider, P. A. A1 - Schneider, W. A1 - Schrittwieser, R. A1 - Schubert, M. A1 - Schweinzer, J. A1 - Scott, B. A1 - Sempf, M. A1 - Sertoli, M. A1 - Siccinio, M. A1 - Sieglin, B. A1 - Sigalov, A. A1 - Silva, A. A1 - Sommer, F. A1 - A. Stäbler A1 - Stober, J. A1 - Streibl, B. A1 - Strumberger, E. A1 - Sugiyama, K. A1 - Suttrop, W. A1 - Tala, T. A1 - Tardini, G. A1 - Teschke, M. A1 - Tichmann, C. A1 - Told, D. A1 - Treutterer, W. A1 - Tsalas, M. A1 - VanZeeland, M. A. A1 - Varela, P. A1 - Veres, G. A1 - Vicente, J. A1 - Vianello, N. A1 - Vierle, T. A1 - Viezzer, E. A1 - Viola, B. A1 - Vorpahl, C. A1 - Wachowski, M. A1 - Wagner, D. A1 - Wauters, T. A1 - Weller, A. A1 - Wenninger, R. A1 - Wieland, B. A1 - Willensdorfer, M. A1 - Wischmeier, M. A1 - Wolfrum, E. A1 - E. Würsching A1 - Yu, Q. A1 - Zammuto, I. A1 - Zasche, D. A1 - Zehetbauer, T. A1 - Zhang, Y. A1 - Zilker, M. A1 - Zohm, H. AB - The medium size divertor tokamak ASDEX Upgrade (major and minor radii 1.65 m and 0.5 m, respectively, magnetic-field strength 2.5 T) possesses flexible shaping and versatile heating and current drive systems. Recently the technical capabilities were extended by increasing the electron cyclotron resonance heating (ECRH) power, by installing 2 × 8 internal magnetic perturbation coils, and by improving the ion cyclotron range of frequency compatibility with the tungsten wall. With the perturbation coils, reliable suppression of large type-I edge localized modes (ELMs) could be demonstrated in a wide operational window, which opens up above a critical plasma pedestal density. The pellet fuelling efficiency was observed to increase which gives access to H-mode discharges with peaked density profiles at line densities clearly exceeding the empirical Greenwald limit. Owing to the increased ECRH power of 4 MW, H-mode discharges could be studied in regimes with dominant electron heating and low plasma rotation velocities, i.e. under conditions particularly relevant for ITER. The ion-pressure gradient and the neoclassical radial electric field emerge as key parameters for the transition. Using the total simultaneously available heating power of 23 MW, high performance discharges have been carried out where feed-back controlled radiative cooling in the core and the divertor allowed the divertor peak power loads to be maintained below 5 MW m −2 . Under attached divertor conditions, a multi-device scaling expression for the power-decay length was obtained which is independent of major radius and decreases with magnetic field resulting in a decay length of 1 mm for ITER. At higher densities and under partially detached conditions, however, a broadening of the decay length is observed. In discharges with density ramps up to the density limit, the divertor plasma shows a complex behaviour with a localized high-density region in the inner divertor before the outer divertor detaches. Turbulent transport is studied in the core and the scrape-off layer (SOL). Discharges over a wide parameter range exhibit a close link between core momentum and density transport. Consistent with gyro-kinetic calculations, the density gradient at half plasma radius determines the momentum transport through residual stress and thus the central toroidal rotation. In the SOL a close comparison of probe data with a gyro-fluid code showed excellent agreement and points to the dominance of drift waves. Intermittent structures from ELMs and from turbulence are shown to have high ion temperatures even at large distances outside the separatrix. VL - 53 UR - http://hdl.handle.net/11858/00-001M-0000-0026-E166-7 IS - 10 U1 - FP U2 - PDG U5 - 0b5b08fdc590c85cc01e6d1db1958848 ER - TY - JOUR T1 - Impact of nitrogen seeding on confinement and power load control of a high-triangularity JET ELMy H-mode plasma with a metal wall JF - Nuclear Fusion Y1 - 2013 A1 - Giroud, C. A1 - G. P. Maddison A1 - Jachmich, S. A1 - Rimini, F. A1 - Beurskens, M. N. A. A1 - Balboa, I. A1 - Brezinsek, S. A1 - Coelho, R. A1 - Coenen, J. W. A1 - Frassinetti, L. A1 - Joffrin, E. A1 - Oberkofler, M. A1 - Lehnen, M. A1 - Liu, Y. A1 - Marsen, S. A1 - McCormick, K. A1 - Meigs, A. A1 - Neu, R. A1 - Sieglin, B. A1 - G. J. van Rooij A1 - Arnoux, G. A1 - Belo, P. A1 - Brix, M. A1 - Clever, M. A1 - Coffey, I. A1 - Devaux, S. A1 - Douai, D. A1 - Eich, T. A1 - Flanagan, J. A1 - S. Grünhagen A1 - Huber, A. A1 - Kempenaars, M. A1 - Kruezi, U. A1 - Lawson, K. A1 - Lomas, P. A1 - Lowry, C. A1 - Nunes, I. A1 - Sirinnelli, A. A1 - Sips, A.C.C. A1 - Stamp, M. A1 - Wiesen, S. A1 - JET-EFDA Contributors AB - This paper reports the impact on confinement and power load of the high-shape 2.5 MA ELMy H-mode scenario at JET of a change from all carbon plasma-facing components to an all metal wall. In preparation to this change, systematic studies of power load reduction and impact on confinement as a result of fuelling in combination with nitrogen seeding were carried out in JET-C and are compared with their counterpart in JET with a metallic wall. An unexpected and significant change is reported on the decrease in the pedestal confinement but is partially recovered with the injection of nitrogen. VL - 53 UR - http://stacks.iop.org/0029-5515/53/i=11/a=113025 U1 - PSI U2 - PSI-E U5 - 7d3797a6a25b0cd8d9b26c4b70a4587d ER - TY - JOUR T1 - Impact of the ITER-like wall on divertor detachment and on the density limit in the JET tokamak JF - Journal of Nuclear Materials Y1 - 2013 A1 - Huber, A. A1 - Brezinsek, S. A1 - Groth, M. A1 - de Vries, P. C. A1 - Riccardo, V. A1 - G. J. van Rooij A1 - Sergienko, G. A1 - Arnoux, G. A1 - Boboc, A. A1 - P. Bilkova A1 - Calabro, G. A1 - Clever, M. A1 - Coenen, J. W. A1 - Beurskens, M. N. A. A1 - Eich, T. A1 - Jachmich, S. A1 - Lehnen, M. A1 - Lerche, E. A1 - Marsen, S. A1 - Matthews, G. F. A1 - McCormick, K. A1 - Meigs, A. G. A1 - Mertens, P. A1 - Philipps, V. A1 - Rapp, J. A1 - Samm, U. A1 - Stamp, M. A1 - Wischmeier, M. A1 - Wiesen, S. AB - L-mode and H-mode density limits with the ITER-like wall (ILW) have been investigated in the recent experimental campaign and compared with experiments in the JET carbon material configuration. The density limit is up to 40% higher in the JET-ILW than in the JET-CFC machine. This is linked to the formerly higher radiation fraction and, correspondingly, to earlier divertor detachment in the JET-CFC. In the ILW configuration, the discharge demonstrates a stable operation with a completely detached outer divertor in L- and H-mode. In contrary to the well-known “heating power independent” Greenwald limit, the L-mode densities limit increases moderately with rising heating power ( ∼ P heat 0.4 ) independently of the wall material. The H–L transition constitutes an effective undisruptive density limit for an H-mode plasma. Detachment itself does not trigger the H–L back transition and does not present a limit on plasma density. In the range of neutral beam heating 8–10.5 MW, no dependence of the H-mode density limit on the heating power was observed. VL - 438, Supplement UR - http://www.sciencedirect.com/science/article/pii/S0022311513000305 N1 -A new pellet injection system was installed at JET designed for both fuelling and ELM pacing. The purpose of the pacing section was to validate pellet ELM pacing as a suitable tool for ELM mitigation in ITER. Pellet pacing was confirmed at the large size scale of JET. The dynamics of triggered ELMs was investigated with respect to their spontaneous counterparts. Triggered ELMs show features also typical for spontaneous ELMs in several operational regimes. Since none of these regimes was unsettled by the pellets this is a strong hint for compatibility with other plasma control tools. Observations and modelling results indicate the ELM triggering occurs by the evolution of the pellet ablation plasmoid into the first ELM filament followed by a poloidal spread of the instability. An ELM obviously can be forced by a pellet due to the strong local perturbation imposed already under unusual onset conditions but then evolves like any ELM typical for the corresponding plasma regime. For tool optimization the pellet mass and hence the convective confinement losses imposed have to be minimized. In our experiments, a lower mass threshold was observed for the first time. It has been found that to reliably trigger an ELM the pellet needs to be sufficiently large (and fast) to penetrate close to the pedestal top. Recent investigations are clear steps forward to validate the pellet pacing approach for ITER.

VL - 51 SN - 0029-5515 IS - 3 N1 - ISI Document Delivery No.: 729AETimes Cited: 4Cited Reference Count: 38 U1 -FP

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U5 - 506bca96c5637433dac75b877a0bcc14 ER - TY - JOUR T1 - Fuel retention in impurity seeded discharges in JET after Be evaporation JF - Nuclear Fusion Y1 - 2011 A1 - Brezinsek, S. A1 - Loarer, T. A1 - Krieger, K. A1 - Jachmich, S. A1 - Tsalas, M. A1 - Coffey, I. A1 - Esser, H. G. A1 - Eich, T. A1 - Fundamenski, W. A1 - Giroud, C. A1 - Grunhagen, S. A1 - Huber, A. A1 - Kruezi, U. A1 - Knipe, S. A1 - G. P. Maddison A1 - McCormick, K. A1 - Meigs, A. G. A1 - Morgan, P. A1 - Philipps, V. A1 - Sergienko, G. A1 - Stagg, R. A1 - Stamp, M. F. A1 - Tabares, F. L. AB -Preparatory experiments for the ITER-Like Wall in JET were carried out to simulate the massive Be first wall by a thin Be layer, induced by evaporation of about 2.0 g Be, and to study its impact on fuel retention and divertor radiation with reduced C content and N seeding. Residual gas analysis reveals a reduction of hydrocarbons by one order of magnitude and of O by a factor of 5 in the partial pressure owing to the evaporation. The evolution of wall conditions, impurity fluxes and divertor radiation have been studied in ELMy H-mode plasmas (B(t) = 2.7T, I(p) = 2.5 MA, P(aux) = 16MW) whereas a non-seeded reference discharge was executed prior to the evaporation. The in situ measured Be flux at the midplane increased by about a factor of 40 whereas the C flux decreased by similar to 50% in the limiter phase of the first discharge with respect to the reference, but erosion of the Be layer and partial coverage with C takes place quickly. To make best use of the protective Be layer, only the first four discharges were employed for a gas balance analysis providing a D retention rate of 1.94 x 10(21) Ds(-1) which is comparable to rates with C walls. But the Be evaporation provides a non-saturated surface with respect to D and short term retention is not negligible in the balance; the measured retention is overestimated with respect to steady-state conditions like that of the ILW. Moreover, C was only moderately reduced and co-deposition of fuel with eroded Be and C occurs. The lower C content leads to a minor reduction in divertor radiation as the reference phase prior to seeding indicates. N adds to the radiation of D and the remaining C, and the N content rises due to the legacy effect which has been quantified by gas balance to be 30% of the injected N. C radiation increases with exposure time, and both contributors cause an increase in the radiated fraction in the divertor from 50% to 70%. The radiation pattern suggests that N dominates the increase in the first discharges though C is still the dominating radiator. Therefore, the validity of a proxy of the Be first wall by a thin Be layer is limited and restricted to plasma operation directly after the Be evaporation.

VL - 51 SN - 0029-5515 UR - http://www.euro-fusionscipub.org/wp-content/uploads/2014/11/EFDP10061.pdf IS - 7 N1 - ISI Document Delivery No.: 781LITimes Cited: 0Cited Reference Count: 13 U1 -FP

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U5 - d2612de26ff79da3d955b0cf79718bb1 ER - TY - JOUR T1 - Moderation of target loads using fuelling and impurity seeding on JET JF - Journal of Nuclear Materials Y1 - 2011 A1 - Maddison, G. A1 - Giroud, C. A1 - McCormick, K. A1 - Alonso, A. A1 - Alper, B. A1 - Andrew, Y. A1 - Arnoux, G. A1 - Belo, P. A1 - Beurskens, M. A1 - Boboc, A. A1 - Brett, A. A1 - Brezinsek, S. A1 - Brix, M. A1 - Coffey, I. A1 - de la Luna, E. A1 - Devaux, S. A1 - P. de Vries A1 - Devynck, P. A1 - Eich, T. A1 - Felton, R. A1 - Fundamenski, W. A1 - Harling, J. A1 - Harting, D. A1 - Hobirk, J. A1 - Huber, A. A1 - Jachmich, S. A1 - Jenkins, I. A1 - Joffrin, E. A1 - Kallenbach, A. A1 - Kempenaars, M. A1 - Lehnen, M. A1 - Loarer, T. A1 - Lomas, P. A1 - McDonald, D. A1 - Meigs, A. A1 - Monier-Garbet, P. A1 - Morgan, P. A1 - Moulton, D. A1 - Riccardo, V. A1 - Rimini, F. A1 - Sergienko, G. A1 - Sirinelli, A. A1 - Stamp, M. A1 - Telesca, G. A1 - Thomsen, H. A1 - Voitsekhovitch, I. KW - ELMY H-MODES KW - RETENTION AB -Operation with an all metal, ITER-like wall on JET is scheduled from 2011. Adaptation particularly of baseline ELMy H-mode (q(95) approximate to 3.5) to the new exhaust constraints involved has been explored by systematic scans of deuterium fuelling and seeding with extrinsic impurities neon or nitrogen. Peak heat load between ELMs on the outboard target can be strongly reduced by fuelling (recycling), and approach detachment with either seed species, for only approximate to 10% loss of normalised energy confinement. Simultaneously, normalised plasma density and total radiation averaged between ELMs are not simply increased, but at stronger fuelling can actually fall with increasing seeding, indicating some redistribution of efflux power temporally and spatially. At highest nitrogen seeding, ELMs can also be mitigated, even while the electron pedestal and confinement are largely preserved. Charge-exchange recombination spectroscopy indicates a substitution of intrinsic carbon with extrinsic species. (C) 2010 EURATOM. Published by Elsevier B.V. All rights reserved.

VL - 415 SN - 0022-3115 IS - 1, Suppl. N1 - ISI Document Delivery No.: 862XTTimes Cited: 5Cited Reference Count: 1019th International Conference on Plasma-Surface Interactions in Controlled Fusion Devices (PSI)MAY 24-28, 2010San Diego, CALawrence Livermore Natl LabS U1 -FP

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U5 - 8d83f5b5cfb0081dac434500d27b5dd4 ER - TY - JOUR T1 - Overview of experimental preparation for the ITER-Like Wall at JET JF - Journal of Nuclear Materials Y1 - 2011 A1 - Brezinsek, S. A1 - Fundamenski, W. A1 - Eich, T. A1 - Coad, J. P. A1 - Giroud, C. A1 - Huber, A. A1 - Jachmich, S. A1 - Joffrin, E. A1 - Krieger, K. A1 - McCormick, K. A1 - Lehnen, M. A1 - Loarer, T. A1 - de la Luna, E. A1 - Maddison, G. A1 - Matthews, G. F. A1 - Mertens, P. A1 - Nunes, I. A1 - Philipps, V. A1 - Riccardo, V. A1 - Rubel, M. A1 - Stamp, M. F. A1 - Tsalas, M. KW - divertor KW - PROJECT KW - Tungsten AB -Experiments in JET with carbon-based plasma-facing components have been carried out in preparation of the ITER-Like Wall with beryllium main chamber and full tungsten divertor. The preparatory work was twofold: (i) development of techniques, which ensure safe operation with the new wall and (ii) provision of reference plasmas, which allow a comparison of operation with carbon and metallic wall. (i) Compatibility with the W divertor with respect to energy loads could be achieved in N-2 seeded plasmas at high densities and low temperatures, finally approaching partial detachment, with only moderate confinement reduction of 10%. Strike-point sweeping increases the operational space further by re-distributing the load over several components. (ii) Be and C migration to the divertor has been documented with spectroscopy and QMBs under different plasma conditions providing a database which will allow a comparison of the material transport to remote areas with metallic walls. Fuel retention rates of 1.0-2.0 x 10(21) D s(-1) were obtained as references in accompanied gas balance studies. (C) 2010 Published by Elsevier B.V.

VL - 415 SN - 0022-3115 IS - 1 N1 - ISI Document Delivery No.: 862XTTimes Cited: 8Cited Reference Count: 1719th International Conference on Plasma-Surface Interactions in Controlled Fusion Devices (PSI)MAY 24-28, 2010San Diego, CALawrence Livermore Natl LabS U1 -FP

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U5 - d47299eebfd541ed3d2532c0cfcec12f ER - TY - JOUR T1 - Plasma surface interactions in impurity seeded plasmas JF - Journal of Nuclear Materials Y1 - 2011 A1 - Kallenbach, A. A1 - Balden, M. A1 - Dux, R. A1 - Eich, T. A1 - Giroud, C. A1 - Huber, A. A1 - G. P. Maddison A1 - Mayer, M. A1 - McCormick, K. A1 - Neu, R. A1 - Petrie, T. W. A1 - Putterich, T. A1 - Rapp, J. A1 - Reinke, M. L. A1 - Schmid, K. A1 - Schweinzer, J. A1 - Wolfe, S. KW - ASDEX UPGRADE KW - BOUNDARY KW - divertor KW - EDGE PROPERTIES KW - H-MODE DISCHARGES KW - HEAT LOAD KW - HIGH-DENSITY KW - IMPROVED CONFINEMENT KW - JET KW - TOKAMAK AB -With tokamak devices developing towards higher heating powers, and carbon plasma facing components being increasingly replaced by high-Z materials like tungsten, impurity seeding for radiative power dissipation gains more importance. This review summarizes the core and divertor radiative characteristics of potential seeding species, namely noble gases and nitrogen. Due to its radiative capability below 10 eV, nitrogen turns out to be a suitable replacement for carbon as a divertor radiator. For typical plasma parameters and high radiation levels, it becomes the most important eroding species for high-Z plasma facing components. Nitrogen exhibits pronounced storage in near-surface tungsten layers in an about 1:1 W/N atomic ratio, which may effect W sputtering. While the inter-ELM erosion of tungsten can be almost completely eliminated by electron temperature reduction, type-I ELMs remain an effective sputtering source. Since a large ELM cannot be significantly ameliorated by radiation, impurity seeding has to be integrated with a benign ELM scenario, like the type-III ELMy H-mode or active ELM control by pellets or resonant magnetic perturbations. (C) 2010 Elsevier B.V. All rights reserved.

VL - 415 SN - 0022-3115 IS - 1, Suppl. N1 - ISI Document Delivery No.: 862XTTimes Cited: 3Cited Reference Count: 4819th International Conference on Plasma-Surface Interactions in Controlled Fusion Devices (PSI)MAY 24-28, 2010San Diego, CALawrence Livermore Natl LabS U1 -PSI

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U5 - 6643b17b2ab92eef6511ae0a8d4e6815 ER - TY - JOUR T1 - Strike-point splitting induced by external magnetic perturbations: Observations on JET and MAST and associated modelling JF - Journal of Nuclear Materials Y1 - 2011 A1 - Nardon, E. A1 - Cahyna, P. A1 - Devaux, S. A1 - Kirk, A. A1 - Alfier, A. A1 - de la Luna, E. A1 - De Temmerman, G. A1 - Denner, P. A1 - Eich, T. A1 - Gerbaud, T. A1 - Harting, D. A1 - Jachmich, S. A1 - Koslowski, H. R. A1 - Liang, Y. A1 - Sun, Y. AB -Heat flux deposition profiles, calculated from infrared imaging, are presented for JET and MAST cases in the presence of external magnetic perturbations. In L-mode, a clear splitting of the strike-point is observed and well reproduced by modelling based on field line tracing with no plasma magnetic response included (vacuum field approximation). In H-mode, in contrast, the splitting is not clearly observed in spite of being expected from vacuum field modelling. As illustrated by modelling results, screening effects could explain the absence of a clear splitting in H-mode. (C) 2010 Elsevier B.V. All rights reserved.

VL - 415 SN - 0022-3115 UR - http://www.euro-fusionscipub.org/wp-content/uploads/2014/11/EFDC100516.pdf IS - 1 N1 - ISI Document Delivery No.: 862XTTimes Cited: 3Cited Reference Count: 1519th International Conference on Plasma-Surface Interactions in Controlled Fusion Devices (PSI)MAY 24-28, 2010San Diego, CALawrence Livermore Natl LabS U1 -PSI

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U5 - 87f3e090e63f522b87bdce9eead79965 ER - TY - JOUR T1 - Type-I ELM power deposition profile width and temporal shape in JET JF - Journal of Nuclear Materials Y1 - 2011 A1 - Eich, T. A1 - Thomsen, H. A1 - Fundamenski, W. A1 - Arnoux, G. A1 - Brezinsek, S. A1 - Devaux, S. A1 - Herrmann, A. A1 - Jachmich, S. A1 - Rapp, J. KW - EXTRAPOLATION KW - HEAT-FLUX KW - ITER AB -A new infra red camera (IR) for high resolution infra red studies for the outer divertor target plate in JET has been installed. Shot integrated energy balance between tile embedded thermocouples and IR based estimation of deposited energy on the outer tile gives fair agreement in the range of 80-120%. The assumptions of the temporal evolution of type-I ELMs power load as made for ITER define a lower, conservative boundary within the observed variation of the data. The broadening of the ELM induced power profiles are, in contrast to earlier results based on a lower resolution IR system at JET, found to be in the range of 1.4-4.3 when compared to the inter-ELM wetted area. (C) 2011 Published by Elsevier B.V.

VL - 415 SN - 0022-3115 IS - 1, Suppl. N1 - ISI Document Delivery No.: 862XTTimes Cited: 10Cited Reference Count: 919th International Conference on Plasma-Surface Interactions in Controlled Fusion Devices (PSI)MAY 24-28, 2010San Diego, CALawrence Livermore Natl LabS U1 -PSI

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U5 - 30dcc77d9a4292044ac2b4e9ba1acbd6 ER - TY - JOUR T1 - Characterization of edge profiles and fluctuations in discharges with type-II and nitrogen-mitigated edge localized modes in ASDEX Upgrade JF - Plasma Physics and Controlled Fusion Y1 - 2011 A1 - Wolfrum, E. A1 - Bernert, M. A1 - Boom, J. E. A1 - Burckhart, A. A1 - Classen, I. G. J. A1 - Conway, G. D. A1 - Eich, T. A1 - Fischer, R. A1 - Gude, A. A1 - Herrmann, A. A1 - Luhmann Jr., N. C. A1 - Maraschek, M. A1 - McDermott, R. A1 - Park, H. K. A1 - T Pütterich A1 - Vicente, J. A1 - Wieland, B. A1 - Willensdorfer, M. A1 - ASDEX Upgrade Team AB - Edge localized modes (ELMs) with high frequency and low power loss (type-II ELMs) occur in high triangularity, near double null configurations in ASDEX Upgrade with full tungsten plasma facing components. The transition from type-I to type-II ELMs is shown to occur above a collisionality threshold. For the first time the characteristic MHD fluctuations around 40 kHz have been localized. The fluctuations are observed in a wide region extending from the pedestal inward to normalized poloidal radius ρ pol = 0.7. Their amplitudes on the low-field side of the plasma exhibit maxima above and below the mid-plane. The fluctuations move in the electron drift direction and lead to a reduced edge electron temperature gradient. The reduction in the edge pressure gradient is connected with these MHD fluctuations, which affect the electron temperature but not the electron density profiles. A comparison with nitrogen-mitigated type-I ELMs in the same plasma shape shows that core profiles are also affected. The electron temperature profile is self-similar for type-I and nitrogen-mitigated type-I ELMs but is not self-similar in the case of type-II ELMs. VL - 53 IS - 8 U1 - FP U2 - PDG U5 - 96834303cba945bc786624fc66aecfbd ER - TY - JOUR T1 - Effect of ELMs on rotation and momentum confinement in H-mode discharges in JET JF - Plasma Physics and Controlled Fusion Y1 - 2010 A1 - Versloot, T. W. A1 - de Vries, P. C. A1 - Giroud, C. A1 - Hua, M. D. A1 - Beurskens, M. N. A. A1 - Brix, M. A1 - Eich, T. A1 - de la Luna, E. A1 - Tala, T. A1 - Naulin, V. A1 - Zastrow, K. D. KW - ASDEX UPGRADE KW - ENERGY KW - I ELMS KW - JT-60U KW - PARTICLE LOSSES KW - TRANSPORT AB - The loss of plasma toroidal angular momentum and thermal energy by edge localized modes (ELMs) has been studied in JET. The analysis shows a consistently larger drop in momentum in comparison with the energy loss associated with the ELMs. This difference originates from the large reduction in angular frequency at the plasma edge, observed to penetrate into the plasma up to r/a similar to 0.65 during large type-I ELMs. As a result, the time averaged angular frequency is lowered near the top of the pedestal with increasing ELM frequency, resulting in a significant drop in thermal Mach number at the edge. An increase in profile peaking of ion temperature and angular frequency is observed. At the same time the plasma confinement is reduced while the ratio of confinement times (R-tau = tau(E)/tau(phi)) increases noticeably with ELM frequency. This change could be explained by the relatively larger ELM induced losses for momentum in combination with the observed longer build-up time for the momentum density at the plasma edge. VL - 52 SN - 0741-3335 UR -