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Core transport properties in JT-60U and JET identity plasmas

(2011) NUCLEAR FUSION. 51(7).
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Abstract
The paper compares the transport properties of a set of dimensionless identity experiments performed between JET and JT-60U in the advanced tokamak regime with internal transport barrier, ITB. These International Tokamak Physics Activity, ITPA, joint experiments were carried out with the same plasma shape, toroidal magnetic field ripple and dimensionless profiles as close as possible during the ITB triggering phase in terms of safety factor, normalized Larmor radius, normalized collision frequency, thermal beta, ratio of ion to electron temperatures. Similarities in the ITB triggering mechanisms and sustainment were observed when a good match was achieved of the most relevant normalized profiles except the toroidal Mach number. Similar thermal ion transport levels in the two devices have been measured in either monotonic or non-monotonic q-profiles. In contrast, differences between JET and JT-60U were observed on the electron thermal and particle confinement in reversed magnetic shear configurations. It was found that the larger shear reversal in the very centre (inside normalized radius of 0.2) of JT-60U plasmas allowed the sustainment of stronger electron density ITBs compared with JET. As a consequence of peaked density profile, the core bootstrap current density is more than five times higher in JT-60U compared with JET. Thanks to the bootstrap effect and the slightly broader neutral beam deposition, reversed magnetic shear configurations are self-sustained in JT-60U scenarios. Analyses of similarities and differences between the two devices address key questions on the validity of the usual assumptions made in ITER steady scenario modelling, e. g. a flat density profile in the core with thermal transport barrier? Such assumptions have consequences on the prediction of fusion performance, bootstrap current and on the sustainment of the scenario.
Keywords
TOKAMAK PLASMAS, NEOCLASSICAL TRANSPORT, BARRIERS, TCV, DENSITY PEAKING

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Chicago
Litaudon, X, Y Sakamoto, PC de Vries, A Salmi, T Tala, C Angioni, S Benkadda, et al. 2011. “Core Transport Properties in JT-60U and JET Identity Plasmas.” Nuclear Fusion 51 (7).
APA
Litaudon, X., Sakamoto, Y., de Vries, P., Salmi, A., Tala, T., Angioni, C., Benkadda, S., et al. (2011). Core transport properties in JT-60U and JET identity plasmas. NUCLEAR FUSION, 51(7).
Vancouver
1.
Litaudon X, Sakamoto Y, de Vries P, Salmi A, Tala T, Angioni C, et al. Core transport properties in JT-60U and JET identity plasmas. NUCLEAR FUSION. 2011;51(7).
MLA
Litaudon, X, Y Sakamoto, PC de Vries, et al. “Core Transport Properties in JT-60U and JET Identity Plasmas.” NUCLEAR FUSION 51.7 (2011): n. pag. Print.
@article{1860609,
  abstract     = {The paper compares the transport properties of a set of dimensionless identity experiments performed between JET and JT-60U in the advanced tokamak regime with internal transport barrier, ITB. These International Tokamak Physics Activity, ITPA, joint experiments were carried out with the same plasma shape, toroidal magnetic field ripple and dimensionless profiles as close as possible during the ITB triggering phase in terms of safety factor, normalized Larmor radius, normalized collision frequency, thermal beta, ratio of ion to electron temperatures. Similarities in the ITB triggering mechanisms and sustainment were observed when a good match was achieved of the most relevant normalized profiles except the toroidal Mach number. Similar thermal ion transport levels in the two devices have been measured in either monotonic or non-monotonic q-profiles. In contrast, differences between JET and JT-60U were observed on the electron thermal and particle confinement in reversed magnetic shear configurations. It was found that the larger shear reversal in the very centre (inside normalized radius of 0.2) of JT-60U plasmas allowed the sustainment of stronger electron density ITBs compared with JET. As a consequence of peaked density profile, the core bootstrap current density is more than five times higher in JT-60U compared with JET. Thanks to the bootstrap effect and the slightly broader neutral beam deposition, reversed magnetic shear configurations are self-sustained in JT-60U scenarios. Analyses of similarities and differences between the two devices address key questions on the validity of the usual assumptions made in ITER steady scenario modelling, e. g. a flat density profile in the core with thermal transport barrier? Such assumptions have consequences on the prediction of fusion performance, bootstrap current and on the sustainment of the scenario.},
  articleno    = {073020},
  author       = {Litaudon, X and Sakamoto, Y and de Vries, PC and Salmi, A and Tala, T and Angioni, C and Benkadda, S and Beurskens, MNA and Bourdelle, C and Brix, M and Cromb{\'e}, Kristel and Fujita, T and Futatani, S and Garbet, X and Giroud, C and Hawkes, NC and Hayashi, N and Hoang, GT and Hogeweij, GMD and Matsunaga, G and Nakano, T and Oyama, N and Parail, V and Shinohara, K and Suzuki, T and Takechi, M and Takenaga, H and Takizuka, T and Urano, H and Voitsekhovitch, I and Yoshida, M},
  issn         = {0029-5515},
  journal      = {NUCLEAR FUSION},
  keyword      = {TOKAMAK PLASMAS,NEOCLASSICAL TRANSPORT,BARRIERS,TCV,DENSITY PEAKING},
  language     = {eng},
  number       = {7},
  pages        = {13},
  title        = {Core transport properties in JT-60U and JET identity plasmas},
  url          = {http://dx.doi.org/10.1088/0029-5515/51/7/073020},
  volume       = {51},
  year         = {2011},
}

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