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Doyle, E. J.*; Houlberg, W. A.*; Kamada, Yutaka; Mukhovatov, V.*; Osborne, T. H.*; Polevoi, A.*; Bateman, G.*; Connor, J. W.*; Cordey, J. G.*; Fujita, Takaaki; et al.
Nuclear Fusion, 47(6), p.S18 - S127, 2007/06
no abstracts in English
McDonald, D. C.*; Cordey, J. G.*; Thomsen, K.*; Kardaun, O. J. W. F.*; Snipes, J. A.*; Greenwald, M.*; Sugiyama, L.*; Ryter, F.*; Kus, A.*; Stober, J.*; et al.
Nuclear Fusion, 47(3), p.147 - 174, 2007/03
Times Cited Count:51 Percentile:29.82(Physics, Fluids & Plasmas)This paper describes the updates to and analysis of the International Tokamak Physics Activity (ITPA) Global H-node Confinement Database version 3 (DB3) over the period 1994-2004. Global data, for the energy confinement time and its controlling parameters, have now been collected from 18 machines of different sizes and shapes: ASDEX, ASDEX Upgrade, C-Mod CoMPASS-D, DIII-D, JET, JFT-2M, JT-60U, MAST, NSTX, PBX-M, PDX, START, T-10, TCV, TdeV, TFTR and TUMAN-3M. A wide range of physics studies has been performed on DB3 with particular progress made in the separation of core and edge behavior, dimensionless parameter analyses and the comparison of the database with one-dimensional transport code. A key aim of the database has always been to provide a basis for estimating the energy confinement properties of next step machines such as ITER, and so the impact of the database and its analysis on such machines is also discussed.
McDonald, D. C.*; Meakins, A. J.*; Svensson, J.*; Kirk, A.*; Andrew, Y.*; Cordey, J. G.*; Takizuka, Tomonori; ITPA H-mode Threshold Database Working Group*
Plasma Physics and Controlled Fusion, 48(5A), p.A439 - A447, 2006/05
Times Cited Count:10 Percentile:34.06(Physics, Fluids & Plasmas)The H-mode power threshold is estimated from the International threshold database by the ordinary least square log-linear regression (OLS), the errors-in-variables log-linear orthogonal regression and the generalized maximum-likekihood (M-L) method. A chi-squared analysis shows that none of the studied models are entirely consistent with the data, indicating that further refinement of the physical and statistical model is required. For ITER-like parameters, a M-L analysis shows a predicted threshold of 38.4 MW, compared with 31.1 MW for the OLS.
Kaye, S. M.*; Valovic, M.*; Chudnovskiy, A.*; Cordey, J. G.*; McDonald, D.*; Meakins, A.*; Thomsen, K.*; Akers, R.*; Bracco, G.*; Brickley, C.*; et al.
Plasma Physics and Controlled Fusion, 48(5A), p.A429 - A438, 2006/05
Times Cited Count:15 Percentile:45.90(Physics, Fluids & Plasmas)The effects of aspect ratio and beta on confinement scaling are studied with the use of the H-mode database extended by the low aspect ratio data from NSTX and MAST. Various statistical methods are applied. Development of scalings using engineering parameters as predictor variables results in the inverse-aspect-ratio scaling with the range from 0.38 to 1.29. The transformation of these scalings to physics variables results in an unfavorouble dependence of the normalized energy confinement time on beta. There is a strong correlation between the inverse aspect ratio and beta, and this makes scalings based on physics variables imprecise.
Cordey, J. G.*; Thomsen, K.*; Chudnovskiy, A.*; Kardaun, O. J. W. F.*; Takizuka, Tomonori; Snipes, J. A.*; Greenwald, M.*; Sugiyama, L.*; Ryter, F.*; Kus, A.*; et al.
Nuclear Fusion, 45(9), p.1078 - 1084, 2005/09
Times Cited Count:51 Percentile:82.17(Physics, Fluids & Plasmas)The condition of the latest version of the ELMy H-mode database has been re-examined. It is shown that there is bias in the ordinary least squares regression for some of the variables. To address these shortcomings three different techniques are employed: (a)principal component regression, (b)an error in variables technique and (c)the selection of a better conditioned dataset with fewer variables. Scalings in terms of the dimensionless physics valiables, as well as the standard set of engineering variables, are derived. The new scalings give a very similar performance for existing scalings for ITER at the standard beta, but a much improvement performance at higher beta.
Saibene, G.*; Hatae, Takaki; Campbell, D. J.*; Cordey, J. G.*; la Luna, E. de.*; Giroud, C.*; Guenther, K.*; Kamada, Yutaka; Kempenaars, M. A. H.*; Loarte, A.*; et al.
Plasma Physics and Controlled Fusion, 46(5A), p.A195 - A205, 2004/05
Times Cited Count:10 Percentile:31.94(Physics, Fluids & Plasmas)Towards establishment of the control scheme and evaluation of the H-mode pedestal structure and behavior of the Edge Localized Mode (ELM) in ITER, we carried out an comparison experiment among the two large tokamaks (JT-60 and JET) for the first time. This paper report the initial results. In both devices, the same plasma shape was adopted and the three non-dimensional parameters (beta, normalized gyro radius and the normalized collisionality) were set identical. The pedestal width was almost similar in the two devices, however the pressure gradient was higher in JET by a factor of 1.5. The possible reason is a small aspect ration in JET.
Mukhovatov, V.*; Shimomura, Yasuo; Polevoi, A. R.*; Shimada, Michiya; Sugihara, Masayoshi; Bateman, G.*; Cordey, J. G.*; Kardaun, O. J. F.*; Pereverzev, G. V.*; Voitsekhovich, I.*; et al.
Nuclear Fusion, 43(9), p.942 - 948, 2003/09
Times Cited Count:43 Percentile:76.46(Physics, Fluids & Plasmas)The values of Q = (fusion power)/(auxiliary heating power) predicted for ITER by three different methods are compared. The first method utilises an empirical confinement time scaling and prescribed radial profiles of transport coefficients, the second approach extrapolates from especially designed ITER similarity experiments, and the third approach is based on partly theory-based transport models. The energy confinement time given by the ITERH-98(y,2) scaling for an inductive scenario with plasma current of 15 MA and plasma density 15% below the Greenwald density is 3.7 s with one estimated technical standard deviation of 14%. This translates in the first approach into an interval for Q of [6-15] at the auxiliary heating power Paux = 40 MW and [6-30] at the minimum heating power satisfying a good confinement ELMy H-mode. Predictions of similarity experiments from JET and of theory-based transport models overlap with the prediction using the empirical confinement-time scaling within its estimated margin of uncertainty.
Ongena, J.*; Budny, R.*; Dumortier, P.*; Jackson, G. L.*; Kubo, Hirotaka; Messiaen, A. M.*; Murakami, Masanori*; Strachan, J. D.*; Sydora, R.*; Tokar, M.*; et al.
Physics of Plasmas, 8(5), p.2188 - 2198, 2001/05
Times Cited Count:49 Percentile:79.65(Physics, Fluids & Plasmas)no abstracts in English
Boucher, D.*; Connor, J. W.*; Houlberg, W. A.*; Turner, M. F.*; Bracco, G.*; Chudnovskiy, A.*; Cordey, J. G.*; Greenwald, M. J.*; Hoang, G. T.*; Hogeweij, G. M. D.*; et al.
Nuclear Fusion, 40(12), p.1955 - 1981, 2000/12
no abstracts in English
Takizuka, Tomonori; Fukuda, Takeshi; Kamada, Yutaka; Kikuchi, Mitsuru; Matsuda, Toshiaki; Miura, Yukitoshi; Naito, Osamu; Tamai, Hiroshi; D.Boucher*; G.Bracco*; et al.
Fusion Energy 1996, 2, p.795 - 806, 1997/00
no abstracts in English
Kaye, S. M.*; Greenwald, M. J.*; U.Stroth*; O.Kardaun*; A.Kus*; Schissel, D. R.*; J.DeBoo*; Bracco, G.*; K.Thomsen*; Cordey, J. G.*; et al.
Nuclear Fusion, 37(9), p.1303 - 1328, 1997/00
Times Cited Count:162 Percentile:96.74(Physics, Fluids & Plasmas)no abstracts in English
Cordey, J. G.*; Takizuka, Tomonori; Miura, Yukitoshi; ; D.Boucher*; J.W.Connor*; Kardaun, O.*; Ryter, F.*; M.F.Turner*; A.Taroni*; et al.
Science, 275(5298), p.290 - 291, 1997/00
no abstracts in English
Kardaun, O.*; Ryter, F.*; Stroth, U.*; Kus, A.*; Deboo, J. C.*; Schissel, D. P.*; Bramson, G.*; Carlstrom, T. N.*; Thomsen, K.*; Campbell, D. J.*; et al.
Plasma Physics and Controlled Nuclear Fusion Research 1992, Vol.3, p.251 - 270, 1993/00
no abstracts in English
Christiansen, J. P.*; Cordey, J. G.*; Thomsen, K.*; A.Tanga*; Deboo, J. C.*; Schissel, D. P.*; T.S.Taylor*; Kardaun, O.*; F.Wagner*; Ryter, F.*; et al.
Nuclear Fusion, 32(2), p.291 - 338, 1992/00
Times Cited Count:73 Percentile:88.63(Physics, Fluids & Plasmas)no abstracts in English