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U5 - e6fbf10944c346e164a89755f84348fd ER - TY - JOUR T1 - Overview of experiments with radiation cooling at high confinement and high density in limited and diverted discharges JF - Plasma Physics and Controlled Fusion Y1 - 1999 A1 - Ongena, J. A1 - Messiaen, A. M. A1 - Unterberg, B. A1 - Budny, R. V. A1 - Bush, C. E. A1 - Hill, K. A1 - Hoang, G. T. A1 - Jackson, G. A1 - Kallenbach, A. A1 - Monier-Garbet, P. A1 - Mueller, D. A1 - Murakami, M. A1 - Staebler, G. A1 - Ryter, F. A1 - Wade, M. A1 - Bell, M. A1 - Boedo, J. A1 - Bonheure, G. A1 - Dumortier, P. A1 - Durodie, F. A1 - Finken, K.H. A1 - Fuchs, G. A1 - Giesen, B. A1 - Hutteman, P. A1 - R. Jaspers A1 - Koch, R. A1 - Kramer-Flecken, A. A1 - Mertens, P. A1 - Moyer, R. A1 - Pospieszczyk, A. A1 - Ramsey, A. A1 - Samm, U. A1 - Sauer, M. A1 - Schweer, B. A1 - Uhlemann, R. A1 - Vandenplas, P. E. A1 - Van Oost, G. A1 - Vervier, M. A1 - van Wassenhove, G. A1 - Waidmann, G. A1 - Weynants, R. R. A1 - Wolf, G. H. A1 - ASDEX Upgrade Team A1 - DIII-D Team A1 - TEXTOR team A1 - Tftr Team A1 - Tore Supra, Team AB - An overview is presented of recent experiments with radiating mantles on limiter and divertor machines, realizing simultaneously high confinement and high density at high-radiation levels. A variety of operational regimes has been observed and the characteristics of each are documented. High-performance plasmas (i.e. edge localized mode (ELM)-free H-mode confinement quality f(H93) greater than or equal to 1 and normalized beta values beta(n) greater than or equal to 2 simultaneously) with radiating mantles have been demonstrated under quasistationary conditions during the maximum flattop time of the machine (equal to tens of confinement times) on DIII-D and TEXTOR-94. Maximum values for beta(n) up to 4 and for the advanced tokamak confinement-stability product beta(n) x f(L89) up to 13, have been obtained in very high confinement mode (VH-mode) like discharges with radiating mantles in DIII-D. There is a striking similarity between improved ohmic confinement discharges (with or without Ne seeding) and radiating mantle discharges, indicating a possible common origin for the confinement improvement observed. Possible scenarios for the application of radiating mantles on larger machines such as JET and JT-60U are indicated. VL - 41 SN - 0741-3335 U5 - a4b81a1ae4f8558230486711dfd95b29 ER - TY - JOUR T1 - High confinement and high density with stationary plasma energy and strong edge radiation cooling in the upgraded Torus experiment for technology oriented research (TEXTOR-94) JF - Physics of Plasmas Y1 - 1997 A1 - Messiaen, A. M. A1 - Ongena, J. A1 - Unterberg, B. A1 - Boedo, J. A1 - Fuchs, G. A1 - R. Jaspers A1 - Konen, L. A1 - Koslowski, H. R. A1 - Mank, G. A1 - Rapp, J. A1 - Samm, U. A1 - Vandenplas, P. E. A1 - Van Oost, G. A1 - van Wassenhove, G. A1 - Waidmann, G. A1 - Weynants, R. R. A1 - Wolf, G. H. A1 - Bertschinger, G. A1 - Bonheure, G. A1 - Brix, M. A1 - Dumortier, P. A1 - Durodie, F. A1 - Finken, K.H. A1 - Giesen, B. A1 - Hillis, D. A1 - Hutteman, P. A1 - Koch, R. A1 - KramerFlecken, A. A1 - Lyssoivan, A. A1 - Mertens, P. A1 - Pospieszczyk, A. A1 - PostZwicker, A. A1 - Sauer, M. A1 - Schweer, B. A1 - Schwelberger, J. A1 - Telesca, G. A1 - Tokar, M. Z. A1 - Uhlemann, R. A1 - Vervier, M. A1 - Winter, J. AB - An overview of the results obtained so far for the radiative I-mode regime on the upgraded Torus Experiment for Technology Oriented Research (TEXTOR-94) [Proceedings of die 16th IEEE Symposium on Fusion Engineering (Institute of Electrical and Electronics Engineers, Piscataway, NJ, 1995), Vol. 1, p. 470] is given. This regime is obtained under quasistationary conditions with edge neon seeding in a pumped limiter tokamak with circular cross section. It combines high confinement and high beta (up to a normalized beta, beta(n) = 2) with low edge q values (down to q(a) = 2.8) and high density even above the Greenwald limit together with dominant edge radiative heat exhaust, and therefore shows promise for the future of fusion research. Bulk and edge properties of these discharges an described, and a detailed account is given of the energy and particle confinement and their scaling. Energy confinement scales linearly with density as for the nonsaturated Ohmic Neo-Alcator scaling, but the usual degradation with total power remains. No deleterious effects of the neon seeding on fusion reactivity and plasma stability have been observed. (C) 1997 American Institute of Physics. VL - 4 SN - 1070-664X U5 - 037ff68bcb3900c7ddfb694848a692ba ER - TY - JOUR T1 - Recent Results on Ion-Cyclotron and Combined Heating of Textor JF - Fusion Engineering and Design Y1 - 1995 A1 - Koch, R. A1 - Messiaen, A. M. A1 - Ongena, J. A1 - Vannieuwenhove, R. A1 - Van Oost, G. A1 - van Wassenhove, G. A1 - Dumortier, P. A1 - Durodie, F. A1 - Vandenplas, P. E. A1 - Vanesteer, D. A1 - Vervier, M. A1 - Weynants, R. R. A1 - Finken, K.H. A1 - Euringer, H. A1 - Philipps, V. A1 - Samm, U. A1 - Unterberg, B. A1 - Winter, J. A1 - Bertschinger, G. A1 - Esser, H. G. A1 - Fuchs, G. A1 - Giesen, B. A1 - Hintz, E. A1 - Hoenen, F. A1 - Hutteman, P. A1 - Konen, L. A1 - Korten, M. A1 - Koslowski, H. R. A1 - KramerFlecken, A. A1 - Lochter, M. A1 - Mank, G. A1 - Pospieszczyk, A. A1 - Schweer, B. A1 - Soltwisch, H. A1 - Telesca, G. A1 - Uhlemann, R. A1 - Waidmann, G. A1 - Wolf, G. H. A1 - Boedo, J. A1 - Gray, D. A1 - Hillis, D. L. A1 - Oyevaar, T. A1 - Tammen, H. F. A1 - Tanabe, T. A1 - Ueda, Y. AB - The recent experimental activity in the field of auxiliary heating and related topics on TEXTOR is reviewed. TEXTOR is equipped with up to 4 MW of ion cyclotron heating power and 3.4 MW of neutral beam injection. The combination of the radiating boundary concept with high auxiliary power has extended the improved confinement domain to the large density regime and demonstrated the viability of the radiating boundary concept for long pulse high power operation. Improved confinement was also achieved in third harmonic heating, characterised by predominant coupling of the RF to the beam ions. Operation of an unshielded antenna with insulated limiters proved that RF sheaths are taking place on the side limiters and are suppressed by insulation. Control of the helium flux by the RF was successfully demonstrated using the interaction of the RF with fast He-3 ions injected by neutral beam. Preliminary tests with a high Z limiter indicate compatibility, and even a positive effect, of the RF. Experience gained in operating unshielded antennas is also commented on. VL - 26 SN - 0920-3796 U5 - 450239f862a46538964cd016ce30beba ER -