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8 results on '"P. Froissard"'

1. Conditioning and high power operation of the lower hybrid current drive launcher in JET

Author

F. Rimini, B. Fischer, J. A. Romero, J.A. Dobbing, C. Gormezano, M. Lennholm, A. Ekedahl, P. Schildand, P. Froissard, F. X. Söldner, and P. Finburg

Subjects
Physics, Power transmission, Jet (fluid), Tokamak, Divertor, Nuclear engineering, Joint European Torus, Plasma, Condensed Matter Physics, Power (physics), law.invention, Nuclear Energy and Engineering, law, Electric field
Abstract

The full lower hybrid current drive (LHCD) system on the Joint European Torus (JET) has been operational since the start of the pumped divertor phase of JET in 1994. By a campaign of vacuum conditioning in the beginning of operation, the power transmission and conditioning of the fuli launcher was speeded up, as compared with the prototype launcher used in 1990/91. After vents of the tokamak, the conditioning can be recovered by -300 vacuum pulses over 3-4 days. Even after extensive conditioning and with efficient pumping, the power handling of the fuli LHCD system on plasma is limited by the maximum electric field in the waveguides, the limit being 400-500 kV/m.

Published
1998
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2. Runaway electron measurements in the JET tokamak

Author

R Martin Solis, P. van Belle, O.N. Jarvis, E Cecil, P Froissard, G.J. Sadler, B Fischer, B Esposito, N. Watkins, Raul Sanchez, J. M. Adams, and F.B. Marcus

Subjects
Physics, Jet (fluid), Tokamak, Turbulence, Astrophysics::High Energy Astrophysical Phenomena, Transport coefficient, Bremsstrahlung, Electron, Plasma, Condensed Matter Physics, law.invention, Magnetic field, Nuclear Energy and Engineering, law, Atomic physics
Abstract

The perpendicular x-ray emission up a to few MeV of runaway electrons has been measured in JET low-density ohmic discharges by means of the fast electron bremsstrahlung profile monitor. A diffusion model simulating the temporal evolution of the line-integrated x-ray signals is used to determine the runaway radial transport coefficient in the central region of the plasma ( for r/a

Published
1996
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3. Modelling of lower hybrid current drive and comparison with experimental results in JET

Author

C. Gormezano, F.G. Rimini, P. Froissard, F. X. Söldner, A. Ekedahl, Yu.F. Baranov, and M. Lennholm

Subjects
Physics, Nuclear and High Energy Physics, Jet (fluid), Wave propagation, Scattering, Electric field, Bremsstrahlung, Electron, Current (fluid), Atomic physics, Diffusion (business), Condensed Matter Physics, Computational physics
Abstract

A new code has been developed and benchmarked with data from lower hybrid current drive (LHCD) experiments in JET. The model includes stochastic radial diffusion of electrons and scattering of lower hybrid (LH) waves. The code is validated by comparing calculated and experimental current drive efficiencies as well as calculated and measured hard X ray bremsstrahlung emission radial profiles. Reasonable agreement has been found for full LH current driven cases and LH plus moderate DC electric field

Published
1996
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4. Review of neutral beam heating on JET for physics experiments and the production of high fusion performance plasmas

Author

R. König, N. Peacock, E. Martin, L. Lauro-Taroni, D.V. Bartlett, B. Ingram, G. Vlases, A. Sibley, C. Terella, C. Lowry, N. A. Gottardi, T. Elevant, G. Saibene, J. Christiansen, M. Baronian, A. Tesini, T. Raimondi, A. J. Bickley, J. How, H. van der Beken, A. Haigh, N. C. Hawkes, M. C. Ramos de Andrade, H. Morsi, G. Murphy, M. Botman, A. Dines, A. Gondhalekar, C. Gormezano, M. Irving, H. Brelen, M. Tabellini, B. Schunke, B.J.D. Tubbing, G. Sadler, P. R. Thomas, C. Gowers, P. E. Stott, G. Corrigan, S. Cooper, W. J. Brewerton, H. D. Falter, M. Keilhacker, A. Korotkov, V. Marchese, M. Cox, P. Breger, M. Nilsen, T. Szabo, M. L. Watkins, R. Claesen, C. J. Hancock, I. D. Young, S. Ali-Arshad, M. J. Watson, O. N. Jarvis, E. Bertolini, C. Walker, S. Clement, Y. Baranov, W. Bailey, G. Celentano, C. Froger, K. D. Lawson, D. Stork, D.F.H. Start, A. Cherubini, R. Monk, S. L. Dmitrenko, H. Jaeckel, S. Richards, C. A. Steed, L. G. Eriksson, S. F. Mills, S. J. Booth, P. G. Doyle, P. Meriguet, R. J. M. Pearce, H. Duquenoy, G. Radford, R. Prentice, F. Jensen, M. A. Pick, C. D. Challis, B. Alper, R. Wolf, J. Lingertat, F. Soldner, M. O'Mullane, N. Deliyanakis, P. Nielsen, A. C. Bell, R. Lasser, E. Deksnis, J. P. Coad, P. J. Harbour, E. M. Jones, T. Budo, F. Marcus, N. Davies, B. Balet, F.G. Rimini, M. Comiskey, T. Wade, P. Burton, T. Bonicelli, P. Gaze, K. Fullard, D. Martin, W. Zwingmann, T. Winkel, M. Ottaviani, P. Massmann, J. O'Rourke, D. Bond, P. Boucquey, P. Barabaschi, R. D. Gill, M. Cooke, B. Patel, W. Suverkroop, A. Kaye, D. Chiron, T. Businaro, D. Goodall, M.F. Stamp, G. B. Denne-Hinnov, R. Ostrom, A. Girard, L. Horton, F. Trevalion, C. Woodward, J. Ehrenberg, M. Johnson, A. Loarte, S. Puppin, R. Simoni, J. Jacquinot, A. Galetsas, W. Obert, M. Schmid, J. F. Junger, J. F. Jaeger, P. Andrew, L. Rossi, K. Borras, P. Smeulders, R. Reichle, A. Rolfe, J. Plancoulaine, P. Chuilon, T. T. C. Jones, R. Barnsley, A. Gibson, P. Card, N. Dolgetta, R. Rookes, M. Rapisarda, A. Colton, P. Schild, H. Buttgereit, M. von Hellermann, C. Perry, Henrik Bindslev, M. Garribba, F. Hurd, J. Mart, C. Sborchia, S. M. Scott, K. Blackler, A. Santagiustina, G. Bosia, C. Cottrell, I. Coffey, G. Newbert, S. Papastergiou, P. Butcher, L. Svensson, G. Vayakis, O. Da Costa, T. Hender, S. Weber, C. F. Maggi, V. V. Parail, P. Froissard, A. Taroni, A.E. Costley, J. P. Poffe, V.P. Bhatnagar, A. C. Maas, Y. Agarici, K. Thomsen, H. McBryan, Francesco Porcelli, H. Altmann, T. J. Wijnands, T. Brown, R. T. Ross, D. O'Brien, R. N. Litunovski, J. J. Davies, R. Russ, P. Kupschus, Annika Ekedahl, G. Magyar, G. Fishpool, H. Deesch, A. C. C. Sips, N. G. Kidd, C. Caldwell-Nichols, T. P. Hughes, M. Newmann, R. Sartori, S. Corti, S. K. Erents, T. Martin, R. Haange, A. M. Edwards, J.A. Dobbing, M. Gadeberg, G. Matthews, Laurie Porte, M. Wykes, D. Wilson, S. J. Davies, J. M. Adams, D. Ward, Wolfgang Kerner, L. Zannelli, J. G. Cordey, A. Tanga, P. Peacock, P. Bertoldi, H. Summers, L. Galbiati, W. J. Dickson, N. P. Hawkes, Michael Loughlin, David Campbell, D. Summers, P. Stangeby, D. Campling, J. L. Hemmerich, G. Benali, S. E. Dorling, J.A. Hoekzema, P. Haynes, J. L. Salanave, F. Junique, M. Salisbury, M. Brusati, J. Wesson, E. Oord, R. Giannella, M. Bures, J. Freiling, G. Janeschitz, M. Huart, E. Righi, G. Sanazzaro, P. J. Lomas, G. Deschamps, P. Stubberfield, M. Lennholm, E. Thompson, B. Macklin, P. J. Howarth, L. P. D. F. Jones, B. E. Keen, P. Noll, M. Brandon, R. Smith, P. Barker, F. Nave, P.D. Morgan, and P. Crawley

Subjects
Physics, Fusion, Jet (fluid), Mechanical Engineering, Nuclear engineering, Plasma, Neutral beam injection, Ion, Nuclear physics, Nuclear Energy and Engineering, Nuclear fusion, General Materials Science, Tritium, Beam (structure), Civil and Structural Engineering
Abstract

The JET neutral beam injection system has proved to be both effective and reliable as a plasma heating device. The ion heating and plasma fuelling characteristics of the system are ideally suited to the production of high fusion performance plasmas while the flexibility in the choice of beam species (H, D, T, 3 He or 4 He) and the ability to inject into almost any JET plasma configuration allows a wide variety of related physics experiments to be carried out. The capability to inject (for the first time) tritium beams was essential to the successful execution of the first tritium experiments in which 1.7 MW of power from DT fusion reactions was generated.

Published
1995
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5. Determination of the suprathermal electron distribution function during lower hybrid current drive in JET

Author

Annika Ekedahl, D.V. Bartlett, A. Airoldi, M. Brusati, R. P. da Silva, P. Froissard, G. Ramponi, and Yves Peysson

Subjects
Physics, Nuclear and High Energy Physics, Jet (fluid), Astrophysics::High Energy Astrophysical Phenomena, Cyclotron, Electron, __, Condensed Matter Physics, Lower hybrid oscillation, law.invention, Magnetic field, Distribution function, law, Plasma diagnostics, Current (fluid), Atomic physics
Abstract

The information provided by different diagnostics has been combined in order to characterize the fast electron distribution function in lower hybrid current drive experiments on JET. In particular, X ray and electron cyclotron emission data are complementary in defining the fast electron energy contents in the directions parallel and perpendicular to the magnetic field. A numerical analysis chain has been developed which identifies the main moments of the distribution function of the current carrying fast electrons and allows simulations based on these moments to be compared with X ray emission, electron cyclotron emission and magnetic data. The method of analysis and the associated diagnostics are described, and results are presented which have been obtained during the lower hybrid current drive campaign on JET.

Published
1994
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6. LHCD OPERATIONS IN JET AND DEVELOPMENTS FOR FUSION APPLICATIONS

Author

A. Kaye, P. Schild, Y. Baranov, P. Finburg, T. McCarthy, J. Plancoulaine, P. Haydon, F.G. Rimini, J.A. Dobbing, A. Ekedahl, G. Agarici, B. Fischer, R. Page, C. Gormezano, P. Paling, M. Brandon, G. Platt, M. Lennholm, P. Froissard, M. Brusati, F. X. Söldner, and D. Pledge

Subjects
Coupling, Physics, Fusion, Jet (fluid), business.industry, Active feedback, Plasma, Aerospace engineering, business, Power (physics)
Abstract

The full Lower Hybrid Current Drive (LHCD) launcher in JET has been completed and installed. Up to 6 MW has been coupled to the plasma and 2 MA full current drive was achieved with 4 MW of LH power. Coupling is improved by using active feedback control on the launcher and plasma position. A new launcher design concept, called Hyperguide, has been developed and tested successfully in JET to replace eventually conventional launchers using multijunctions for next step machines like ITER.

Published
1995
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7. First results with the modified JET

Author

S. Clement, P. Nielsen, D. V. Bartlett, R. Goulding, M. Bures, P. Boucquey, R. Claesen, M. Cox, P. Breger, W. Suverkropp, M. L. Watkins, S. Richards, C. J. Hancock, I. D. Young, P. Card, T. Raimondi, H. Jaeckl, R. Ostrom, J. Mart, Henrik Bindslev, E. van der Goot, C. Woodward, D. Summers, R. König, B. Schunke, T. Hender, E. Thompson, F. Sartori, F. Cecil, P. Chuilon, T. T. C. Jones, S. Milani, G. Saibene, R. Prentice, B. Macklin, L. Svensson, J. Lingertat, P. Smeulders, R. L. Shaw, N. Watkins, R. J. M. Pearce, H. van der Beken, N. C. Hawkes, J. Jacquinot, P. Stubberfield, N. G. Kidd, T. P. Hughes, T. Elevant, R. Monk, W. Zwingmann, J.A. Hoekzema, S. Papastergiou, G. Vlases, R. Lasser, B. Fischer, S. L. Dmitrenko, C. D. Challis, L. Lauro-Taroni, F. Hurd, R. T. Ross, R. Cusack, D. Wilson, H. Brelen, David Campbell, A. C. Maas, G. Cottrell, E. Bertolini, J. How, J. Plancoulaine, R. Russ, O. Da Costa, K. Lawson, J. P. Poffe, N. Peacock, L. Porte, L. Galbiati, S. Ali-Arshad, B. Ingram, B. Alper, R. Wolf, K. Fullard, E. Oord, H. Altmann, A. M. Edwards, C. Terella, C. Lowry, D. Martin, E. Deksnis, A. Rossi, D. O'Brien, S. J. Davies, J. J. Davis, F. Marcus, R. Giannella, C. Walker, V. Bhatnagar, C. A. Steed, A. Gibson, F. Jensen, A. Ekedahl, M. Baronian, J. M. Adams, M. A. Pick, E. M. Jones, N. P. Hawkes, G. D'Antona, P. Schild, L. Horton, J. Freiling, D. Bond, G. Sadler, Wolfgang Kerner, D. Stork, N. Davies, S. K. Erents, R. Simonini, Michael Loughlin, M. Stamp, M. Schmid, P. J. Harbour, L. Zannelli, M. Schaffer, R. D. Gill, F. Nguyen, M. Gadeberg, A. Tanga, A. Haigh, B. Balet, F. Junique, G. Matthews, M. Johnson, G. Sanazzaro, P. R. Thomas, T. Budd, J. L. Hemmerich, G. Benali, A. Peacock, S. E. Dorling, G. McCormick, J. Dobbing, J. F. Jaeger, P. Andrew, P. Froissard, C. Perry, A. Santagiustina, M. von Hellermann, W. Bailey, D. Ward, C. Caldwell-Nichols, B. Patel, G. Celentano, T. Wade, V. V. Parail, T. Businaro, E. Lazzaro, A. C. Bell, G. Vayakis, G. Fishpool, H. Deesch, F. Rimini, S. Colombi, S. Puppin, B. Tubbing, W. Obert, A. C. C. Sips, F. Soldner, J. Christiansen, A. Sibley, N. Zornig, A. Rookes, M. Salisbury, A. Kaye, D. Chiron, N. A. Gottardi, J. Wesson, S. Sharapov, T. Martin, S. Weber, P. Lomas, D. Campling, P. Lamalle, A. Rolfe, M. Cooke, D. Goodall, A. J. Bickley, N. Deliyanakis, P. Morgan, A. Tesini, B. Fechner, I. Hutchinson, M. Garribba, R. Reichle, F. Porcelli, R. Barnsley, G. Newbert, G. Murphy, M. Tabellini, P. Stangeby, M. Huart, S. Cooper, E. Righi, L. Rossi, K. Borras, L. G. Eriksson, C. F. Maggi, C. Froger, J. G. Cordey, N. Dolgetta, H. Buttgereit, O. Pogutse, Y. Agarici, S. M. Scott, S. Ishida, D. F. Start, P. E. Stott, A. Meigs, W. J. Brewerton, H. D. Falter, M. Keilhacker, J. P. Coad, V. Marchese, A. Dines, A. Gondhalekar, M. Irving, C. Gowers, H. Guo, K. Thomsen, C. Laviron, C. Gormezano, A. Taroni, A. Howman, P. Kupschus, T. Szabo, M. Ottaviani, P. Burton, P. Ageladarakis, O. N. Jarvis, J. Ehrenberg, P. Savrukhin, T. Bonicelli, M. J. Watson, Y. Baranov, H. Duquenoy, T. Brown, Ambrogio Fasoli, P. G. Doyle, P. Crawley, G. Radford, L. P. D. F. Jones, B. E. Keen, P. Noll, M. Brandon, U. Gerstel, T. Winkel, R. Smith, J. F. Junger, E. Lyadina, P. Barker, F. Nave, P. J. Howarth, M. Lennholm, K. Blackler, H. McBryan, C. Grisolia, R. Sartori, and H. Summers

Subjects
Physics, Jet (fluid), Nuclear engineering, Divertor, Plasma, Condensed Matter Physics, Power (physics), Nuclear physics, Nuclear Energy and Engineering, ___, Power handling, Electron heating, Current (fluid), Scaling
Abstract

JET was extensively modified in the 1992/93 shutdown. The new pumped divertor and many new systems were brought into operation early in 1994. Operations have progressed to 4MA plasma current and, with substantial additional heating, H-mode confinement results confirm the expected scaling. The high power handling capability of the pumped divertor with sweeping is estimated at 20MW for 20s. H-mode plasmas have large Type I ELMs. With lower hybrid heating alone, 2MA full current drive has been achieved with good efficiency, with ICRF power, effective heating and direct electron heating have been demonstrated.

Published
1994
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8. Recent Results from the Lower Hybrid Current Drive Experiment on JET

Author

M. Brusati, M. Lennholm, P. Froissard, M. Pain, D. Start, C. Gormezano, P. Schild, J. Jacquinot, A. Ekedahl, M. C. R. de Andrade, P. J. Lomas, and F.G. Rimini

Subjects
Jet (fluid), Chemistry, Bremsstrahlung, Limiter, Flux, Electron temperature, Plasma, Atomic physics, Current (fluid), Ohmic contact
Abstract

The JET Lower Hybrid Current Drive (LHCD) prototype system has been in operation in the early part of the 1991 experimental campaign with generated power up to 2.7 MW at 3.7 GHz and coupled power to the plasma up to 2.4 MW. Experiments have focused so far on the determination of the performance limits of the system, both in terms of long pulse operation and of replacement of the ohmically driven plasma current. Further experiments have also been carried out to confirm early findings of central electron heating induced by LH when applied in combination with Ion Cyclotron Resonance Heating (ICRH). Long pulse operation has been obtained on JET with 2 MA, 1.9 T limiter plasmas with 1 minute current flat top where 40% of the required flux is provided by the combined application of the LH and ICRF systems. Full replacement of the inductive current has been observed in 1 MA, 3.4 T ohmic plasmas with 1.9 MW of LH power, with current drive efficiencies up to 〈ne〉 Icd/Plh∼0.35 1020 m −2 A/W with volume averaged ele...

Published
1992
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