TY - JOUR
T1 - The radio frequency heating of magnum-psi
JF - Fusion Science and Technology
Y1 - 2005
A1 - Koch, R.
A1 - Messiaen, A. M.
A1 - N.J. Lopes Cardozo
VL - 47
SN - 1536-1055
UR - ://000226380900056
U1 - Fusion Physics
U2 - PSI experimental
U5 - be1e76b5c5ecad7a2a0c1e31b5573443
ER -
TY - JOUR
T1 - The radiative improved mode in textor: Power exhaust and improved confinement at high density
JF - Fusion Science and Technology
Y1 - 2005
A1 - Unterberg, B.
A1 - Samm, U.
A1 - Tokar, M. Z.
A1 - Messiaen, A. M.
A1 - Ongena, J.
A1 - R. Jaspers
VL - 47
SN - 1536-1055
UR - ://000226876100014
U1 - Fusion Physics
U2 - Instrumentation development
U5 - 8c6bb439d9acda3e8817b641dc24e11a
ER -
TY - JOUR
T1 - Predictive modelling of the impact argon injection on H-mode plasmas in JET with the RITM code
JF - Plasma Physics and Controlled Fusion
Y1 - 2004
A1 - Unterberg, B.
A1 - Kalupin, D.
A1 - Tokar, M. Z.
A1 - Corrigan, G.
A1 - Dumortier, P.
A1 - Huber, A.
A1 - Jachmich, S.
A1 - Kempenaars, M.
A1 - Kreter, A.
A1 - Messiaen, A. M.
A1 - Monier-Garbet, P.
A1 - Ongena, J.
A1 - M. E. Puiatti
A1 - Valisa, M.
A1 - von Hellermann, M.
VL - 46
SN - 0741-3335
UR - ://000221876300027
N1 - Suppl. 5A
U1 - Fusion Physics
U2 - Instrumentation development
U5 - 4840b60202960765a6b4d1a5790ff35b
ER -
TY - JOUR
T1 - Comparison of L-mode regimes with enhanced confinement by impurity seeding in JET and DIII-D
JF - Plasma Physics and Controlled Fusion
Y1 - 2002
A1 - Jackson, G. L.
A1 - Murakami, M.
A1 - Baker, D. R.
A1 - Budny, R.
A1 - Charlet, M.
A1 - M.R. de Baar
A1 - Dumortier, P.
A1 - Evans, T. E.
A1 - Groebner, R. J.
A1 - Hawkes, N. C.
A1 - Hillis, D. L.
A1 - Ingesson, L. C.
A1 - Joffrin, E.
A1 - Koslowski, H. R.
A1 - Lawson, K. D.
A1 - Maddison, G.
A1 - McKee, G. R.
A1 - Messiaen, A. M.
A1 - Monier-Garbet, P.
A1 - M F F Nave
A1 - Ongena, J.
A1 - Rapp, J.
A1 - Sartori, F.
A1 - Staebler, G. M.
A1 - Stamp, M.
A1 - Strachan, J. D.
A1 - Tokar, M.
A1 - Unterberg, B.
A1 - von Hellermann, M.
A1 - Wade, M. R.
VL - 44
SN - 0741-3335
UR - ://000178415900008
U1 - Fusion Physics
U2 - Tokamak physics
U5 - 68b2e8cf0a8c32c1a473c0675fb5b7ce
ER -
TY - JOUR
T1 - Confinement properties of high density impurity seeded ELMy H-mode discharges at low and high triangularity on JET
JF - Plasma Physics and Controlled Fusion
Y1 - 2002
A1 - Dumortier, P.
A1 - Andrew, P.
A1 - Bonheure, G.
A1 - Budny, R. V.
A1 - Buttery, R.
A1 - Charlet, M.
A1 - Coffey, I.
A1 - de M. Baar
A1 - de Vries, P. C.
A1 - Eich, T.
A1 - Hillis, D.
A1 - Ingesson, C.
A1 - Jachmich, S.
A1 - Jackson, G.
A1 - Kallenbach, A.
A1 - Koslowski, H. R.
A1 - Lawson, K. D.
A1 - Liu, C.
A1 - Maddison, G.
A1 - Messiaen, A. M.
A1 - Monier-Garbet, P.
A1 - Murakami, M.
A1 - M F F Nave
A1 - Ongena, J.
A1 - Parail, V.
A1 - M. E. Puiatti
A1 - Rapp, J.
A1 - Sartori, F.
A1 - Stamp, M.
A1 - Strachan, J. D.
A1 - Suttrop, W.
A1 - Telesca, G.
A1 - Tokar, M.
A1 - Unterberg, B.
A1 - Valisa, M.
A1 - von Hellermann, M.
A1 - Weyssow, B.
VL - 44
SN - 0741-3335
UR - ://000178415900005
U1 - Fusion Physics
U2 - Instrumentation development
U5 - 68c870a1f9f186cafff6c169e8f363c9
ER -
TY - JOUR
T1 - Radiation pattern and impurity transport in argon seeded ELMy H-mode discharges in JET
JF - Plasma Physics and Controlled Fusion
Y1 - 2002
A1 - M. E. Puiatti
A1 - Mattioli, M.
A1 - Telesca, G.
A1 - Valisa, M.
A1 - Coffey, I.
A1 - Dumortier, P.
A1 - Giroud, C.
A1 - Ingesson, L. C.
A1 - Lawson, K. D.
A1 - Maddison, G.
A1 - Messiaen, A. M.
A1 - Monier-Garbet, P.
A1 - Murari, A.
A1 - M F F Nave
A1 - Ongena, J.
A1 - Rapp, J.
A1 - Strachan, J.
A1 - Unterberg, B.
A1 - von Hellermann, M.
VL - 44
SN - 0741-3335
UR - ://000178415900006
U1 - Fusion Physics
U2 - Instrumentation development
U5 - b7de26cb1ddd1d27983717104d80d676
ER -
TY - JOUR
T1 - Quasistationary high confinement discharges with trans-greenwald density on TEXTOR-94
JF - Physical Review Letters
Y1 - 2000
A1 - Mank, G.
A1 - Messiaen, A. M.
A1 - Ongena, J.
A1 - Unterberg, B.
A1 - Dumortier, P.
A1 - Finken, K.H.
A1 - R. Jaspers
A1 - Koslowski, H. R.
A1 - Kramer-Flecken, A.
A1 - Rapp, J.
A1 - Samm, U.
A1 - van Wassenhove, G.
A1 - Weynants, R. R.
A1 - TEXTOR team
AB - Confinement quality as good as ELM-free H-mode at densities substantially above die Greenwald density limit((n) over bar(e,0)/n(GW) = 1.4) has been obtained in discharges with a radiative boundary under quasistationary conditions for 20 times the energy confinement time. This is achieved by optimizing the gas-fueling rate of RI-mode discharges which tailors their favorable energy confinement and lends to discharges with beta values just below the operational limit beta(n) = 2 of TEXTOR-94, thereby effectively avoiding confinement back transitions or disruptions. In addition, this high-density regime is favorable for helium removal and results in figures of merit tau(p,He)(*)/tau(E) approximate to 10-15, relevant for a future fusion power reactor.
VL - 85
SN - 0031-9007
U5 - d679c92594af854770fedce713c401d7
ER -
TY - JOUR
T1 - Neon radiation efficiency for different confinement regimes in TEXTOR-94
JF - Nuclear Fusion
Y1 - 2000
A1 - Telesca, G.
A1 - Unterberg, B.
A1 - R. Jaspers
A1 - Messiaen, A. M.
A1 - Ongena, J.
A1 - Rapp, J.
A1 - Samm, U.
A1 - Schoon, N.
A1 - Lehnen, M.
A1 - Tokar, M.
A1 - Van Oost, G.
A1 - Zagorski, R.
AB - For neon seeded discharges the quantity [DeltaP(rad)/DeltaZ(eff)(0)]/<()over bar>(2)(e0), which depends linearly on the effective neon cooling rates and which can be taken as a measure of the radiation efficiency of neon, is not a constant for a given machine. When, according to the mode of operation, [[DeltaP(rad)/DeltaZ(eff)(0)]/<()over bar>(2)(e0) is high, radiative power exhaust can be efficiently achieved at low Z(eff) The value of this ratio, which we refer to as the quality of neon cooling, is found to be correlated not only with the plasma edge temperature but also, and even more strongly, with the confinement properties of the discharges. Two different high confinement radiative regimes in TEXTOR-94 have been compared: radiative improved (RI) mode (highest confinement) and gas puff/pure radiofrequency mode (slightly lower confinement). Although the electron temperature profile is similar in the two regimes, due to feedback control of the input power level, it has been found experimentally that the quality of neon cooling is lower for the RI mode than for the gas puff/pure radiofrequency one. Similar behaviour has been observed for the quality of cooling of the residual intrinsic carbon, determined with independent diagnostics and methods. Simulations with the self-consistent RITM code confirm that particle transport, in particular the perpendicular diffusivity at the edge, is a key parameter to determine the level of the power radiated at the edge for a given impurity concentration in the plasma core.
VL - 40
SN - 0029-5515
U5 - 66b93b69e28b4e9cfd7a27bc5f595fcd
ER -
TY - JOUR
T1 - Pellet fuelling into radiative improved confinement discharges in TEXTOR-94
JF - Nuclear Fusion
Y1 - 2000
A1 - Hobirk, J.
A1 - Messiaen, A. M.
A1 - Finken, K.H.
A1 - Ongena, J.
A1 - Brix, M.
A1 - R. Jaspers
A1 - Koslowski, H. R.
A1 - Kramer-Flecken, A.
A1 - Mank, G.
A1 - Rapp, J.
A1 - Telesca, G.
A1 - Unterberg, B.
AB - Normally pellet injection in strongly heated discharges leads at most to a relatively short improvement of the energy and particle confinement times. In contrast to this finding, the radiative improved (RI) mode plasma of TEXTOR-94 is a very well suited target for pellet injection: the interaction of a pellet with the high density plasma together with the radiatively cooled edge leads in the best cases to an improved energy confinement time which lasts to the end of the heating phase. The pellet injection causes at first a density increase; this phase is followed by a quick partial particle loss and later an increase to a quasi-stationary value. Because of the linear density dependence of RI mode confinement this leads to an additional increase in energy confinement time.
VL - 40
SN - 0029-5515
U5 - 3837997950591be2fa71cb06059f09e4
ER -
TY - JOUR
T1 - MHD activity at the beta limit in RI mode discharges on TEXTOR-94
JF - Nuclear Fusion
Y1 - 2000
A1 - Koslowski, H. R.
A1 - Fuchs, G.
A1 - R. Jaspers
A1 - Kramer-Flecken, A.
A1 - Messiaen, A. M.
A1 - Ongena, J.
A1 - Rapp, J.
A1 - SchÃ¼ller, F. C.
A1 - Tokar, M. Z.
AB - The beta limit in radiative improved (RI mode) discharges where energy confinement is enhanced due to an increased radiation level from the edge by impurity seeding of neon has been investigated. Under these discharge conditions spontaneous confinement transitions from higher to lower energy confinement can be observed when the beta limit is approached. The empirically determined limit of the normalized toroidal beta, PN, is 2.2, pp reaches values up to 1.5 in the circular limiter tokamak TEXTOR-94. The sawtooth activity is often stabilized and replaced by central mode oscillations around q = 1 when high values (greater than or equal to 1) of the confinement enhancement factor f(H93) With respect to the ELM-free ITER-93H mode scaling are reached. Measurements of the plasma current distribution show that already before the confinement transition the central current density decreases, i.e. the current profile broadens and magnetic shear is decreased. The deterioration of energy confinement has been found to correlate with the onset of MHD activity either at the q = 1.5 and/or the q = 2 surface. The enhanced transport after the beta drop is caused by the MHD mode activity in the plasma; the favourable stabilization of the ITG mode under RI mode conditions is not altered. The possible role of pressure driven contributions to the destabilization of the observed MHD modes will be discussed.
VL - 40
SN - 0029-5515
U5 - f94700a6ab15f8582f7d02f8b148253f
ER -
TY - JOUR
T1 - Overview of radiative improved mode results on TEXTOR-94
JF - Nuclear Fusion
Y1 - 1999
A1 - Weynants, R. R.
A1 - Messiaen, A. M.
A1 - Ongena, J.
A1 - Unterberg, B.
A1 - Bonheure, G.
A1 - Dumortier, P.
A1 - R. Jaspers
A1 - Koch, R.
A1 - Koslowski, H. R.
A1 - Kramer-Flecken, A.
A1 - Mank, G.
A1 - Rapp, J.
A1 - Tokar, M. Z.
A1 - van Wassenhove, G.
A1 - Biel, W.
A1 - Brix, M.
A1 - Durodie, F.
A1 - Esser, G.
A1 - Finken, K.H.
A1 - Fuchs, G.
A1 - Giesen, B.
A1 - Hobirk, J.
A1 - Huttemann, P.
A1 - Lehnen, M.
A1 - Lyssoivan, A.
A1 - Mertens, P.
A1 - Pospieszczyk, A.
A1 - Samm, U.
A1 - Sauer, M.
A1 - Schweer, B.
A1 - Uhlemann, R.
A1 - Van Oost, G.
A1 - Vandenplas, P. E.
A1 - Vervier, M.
A1 - Philipps, V.
A1 - Waidmann, G.
A1 - Wolf, G. H.
AB - The radiative improved (RI) mode is a tokamak regime offering many attractive reactor features. In the article, the RI mode of TEXTOR-94 is shown to follow the same scaling as the linear ohmic confinement regime and is thus identified as one of the most fundamental tokamak operational regimes. The current understanding derived from experiments and modelling of the conditions necessary for sustaining the mode is reviewed, as are the mechanisms leading to L-RI mode transition. The article discusses the compatibility of high impurity seeding with the low central power density of a burning reactor, as well as RI mode properties at and beyond the Greenwald density.
VL - 39
SN - 0029-5515
U5 - d8925aa0d22855a9d5ab471016f6b56a
ER -
TY - JOUR
T1 - Evidence of suppression of ITG-instability in the radiatively improved mode in TEXTOR-94
JF - Plasma Physics and Controlled Fusion
Y1 - 1999
A1 - Tokar, M. Z.
A1 - R. Jaspers
A1 - Weynants, R. R.
A1 - Koslowski, H. R.
A1 - Kramer-Flecken, A.
A1 - Messiaen, A. M.
A1 - Ongena, J.
A1 - Unterberg, B.
AB - Characteristics of the toroidal ITG-instability are analysed for conditions of the L-mode and the radiatively improved (RI) mode triggered in TEXTOR-94 by puffing of neon. Analysis is performed for experimentally measured profiles of the plasma parameters and densities of impurity species. It is shown that in the Pi-mode the anomalous transport induced by this kind of instability is reduced significantly in a large part of the plasma volume. This is an important channel of the energy confinement improvement. The role of the radial electric field is envisaged.
VL - 41
SN - 0741-3335
U5 - ac767b5ef95307e83f7e8e29938e30e0
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 - Confinement mechanisms in the radiatively improved mode
JF - Plasma Physics and Controlled Fusion
Y1 - 1999
A1 - Tokar, M. Z.
A1 - R. Jaspers
A1 - Koslowski, H. R.
A1 - Kramer-Flecken, A.
A1 - Messiaen, A. M.
A1 - Ongena, J.
A1 - Rogister, A. A.
A1 - Unterberg, B.
A1 - Weynants, R. R.
AB - The characteristics of the toroidal ion temperature gradient (ITG) instability, considered as the main source of anomalous transport in the low (L) confinement mode of tokamaks, are analysed for the conditions of the radiatively improved (RI) mode triggered by seeding of impurities. Based on experimental profiles from TEXTOR-94 we deduce that the ITG-induced turbulence is quenched in the RI-mode in a large part of the plasma radius. Under those conditions the dissipative trapped electron (DTE) instability dominates the transport. The peaking of the electron density, one of the most remarkable features of the L-RI transition, is explained by the difference in contributions of ITG and DTE unstable modes to the diffusive and convective components of the electron flow. The shearing of the plasma toroidal velocity observed in the RI-modes with unbalanced neutral injection is successfully modelled by taking into account both the anomalous plasma viscosity due to ITG-turbulence and predictions of the revisited neoclassical theory.
VL - 41
SN - 0741-3335
U5 - c2f8f981a0aceef5a6790d561084f208
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 - High confinement and high density with stationary plasma energy and strong edge radiation in the TEXTOR-94 tokamak
JF - Physical Review Letters
Y1 - 1996
A1 - Messiaen, A. M.
A1 - Ongena, J.
A1 - Samm, U.
A1 - Unterberg, B.
A1 - van Wassenhove, G.
A1 - Durodie, F.
A1 - R. Jaspers
A1 - Tokar, M. Z.
A1 - Vandenplas, P. E.
A1 - Van Oost, G.
A1 - Winter, J.
A1 - Wolf, G. H.
A1 - Bertschinger, G.
A1 - Bonheure, G.
A1 - Dumortier, P.
A1 - Euringer, H.
A1 - Finken, K.H.
A1 - Fuchs, G.
A1 - Giesen, B.
A1 - Koch, R.
A1 - Konen, L.
A1 - Konigs, C.
A1 - Koslowski, H. R.
A1 - KramerFlecken, A.
A1 - Lyssoivan, A.
A1 - Mank, G.
A1 - Rapp, J.
A1 - Schoon, N.
A1 - Telesca, G.
A1 - Uhlemann, R.
A1 - Vervier, M.
A1 - Waidmann, G.
A1 - Weynants, R. R.
AB - Stationary high energy confinement is observed on TEXTOR-94 for times limited only by the flux swing of the transformer using strong edge radiation cooling. Necessary tools are the feedback control of the radiated power and of the plasma energy content. At the highest densities obtained (up to 1.2 times the Greenwald limit), energy confinement exceeds the edge-localized-mode-free H-mode scaling ITERH93-P by more than 20%. beta limits of TEXTOR-94 are reached with f(H89)/q(a) approximate to 0.6 No detrimental effect of the seeded impurity is seen. These high confinement discharges meet many conditions necessary for a fusion reactor regime.
VL - 77
SN - 0031-9007
U5 - deb38c04f581d00fb67801bc857ea35e
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 -
TY - JOUR
T1 - Review of Recent Advances in Heating and Current Drive on Textor
JF - Plasma Physics and Controlled Fusion
Y1 - 1993
A1 - Messiaen, A. M.
A1 - Van Eester, D.
A1 - Koch, R.
A1 - Ongena, J.
A1 - van Wassenhove, G.
A1 - Weynants, R. R.
A1 - Borgermans, P.
A1 - Conrads, H.
A1 - Dumortier, P.
A1 - Durodie, F.
A1 - Fuchs, G.
A1 - Euringer, H.
A1 - Giesen, B.
A1 - Hillis, D.
A1 - Hoenen, F.
A1 - Koslowski, H. R.
A1 - KramerFlecken, A.
A1 - Lochter, M.
A1 - Oyevaar, T.
A1 - Soltwisch, H.
A1 - Tammen, H. F.
A1 - Telesca, G.
A1 - Uhlemann, R.
A1 - van den Durpel, L.
A1 - Vandenplas, P. E.
A1 - Soltwisch, H.
A1 - Tammen, H. F.
A1 - Telesca, G.
A1 - Uhlemann, R.
A1 - van den Durpel, L.
A1 - Vandenplas, P. E.
A1 - Vannieuwenhove, R.
A1 - Van Oost, G.
A1 - Vervier, M.
A1 - Waidmann, G.
AB - Co-injection (DO --> D+) applied to TEXTOR leads to a hot ion node regime with enhanced confinement. A synergistic increase of the beam effects is observed with the addition of ICRH at omega = 2omega(cD) = omega(cH) (H minority heating scenario) resulting, beside other reviewed effects, in a significant increase of the ion temperature and of the beam driven current (respectively larger than 30 % and 50 % for the addition of an RF power comparable to the NBI one). The large ion heating efficiency of ICRH also remains when ICRH is added to balanced injection and the hot ion mode regime remains up to the maximum achieved beta (=2/3 of the Troyan limit with more than 6MW of auxiliary heating). ICRH also leads to the formation of a more 'isotropic' tail. These results are interpreted with the help of a Fokker-Planck code which computes the beam distribution function in presence of RF and of TRANSP simulations. The amount of RF absorption by the H minority by the ion beam and die bulk plasma is theoretically evaluated. It is shown that a large part of the synergistic effects can be explained by the rise of the electron temperature due to the minority heating which increases the beam slowing down time and its critical energy. A smaller contribution to the effects is due to direct coupling of the RF power to the beam (less than 10 % of the total RF absorbed power) and to the decrease of the plasma toroidal rotation induced by the RF. ICRH has also been added to co-injection at omega = 3omega(CD). In this case no minority heating is present and the RF energy coupling to the beam is one of the dominant effects. It leads to the formation of a very energetic tail of the ion beam with a strong increase of the beam-target neutron reactivity.
VL - 35
SN - 0741-3335
U5 - 776e534e7dc4a86e8d5264ae11eecc6d
ER -