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Sample records for tore supra ergodic

  1. Edge plasma control: Particle channeling in Tore Supra pump limiter and ergodic divertor

    International Nuclear Information System (INIS)

    Ghendrih, P.; Samain, A.; Grosman, A.; Capes, H.; Morera, J.P.

    1989-01-01

    Improved pumping efficiency can be achieved on Tore Supra by channeling process for particles, i.e. channeling of neutrals in the throat of pump limiters and channeling of plasma towards neutralizer plates in the ergodic divertor. The plugging length for the pump limiter throat is computed and numerical evidence of plasma flux channeling between the conductor bars of the ergodic divertor is presented. The effect of the Tore Supra ergodic divertor on edge plasma state and edge plasma transport is discussed. (orig.)

  2. Plasma decontamination during ergodic divertor experiments in TORE SUPRA

    International Nuclear Information System (INIS)

    Monier-Garbet, P.; DeMichelis, C.; Fall, T.; Ghendrih, Ph.; Goniche, M.; Grosman, A.; Hess, W.; Mattioli, M.

    1991-01-01

    In Tore Supra an ergodic divertor (ED) has been integrated in the machine design and successfully operated, as already reported. This paper analyses the decontamination effect resulting from the creation of an ergodic boundary zone. Two plasma geometrical configurations (outboard and inboard) are studied, the plasma being limited respectively either, on the low field side (lfs), by an outboard limiter (3 to 5 cm ahead of the ED modules) or, on the high field side (hfs), by the graphite inner wall. Strong decontamination effects have already been reported for the first configuration by observing line emission of the intrinsic (carbon and oxygen) and purposely injected (nitrogen) impurities. When limited by the inner wall, the plasma is several centimeters farther from the ED modules than in the lfs configuration. The magnetic perturbation is then greatly reduced, and much smaller decontamination effects should be expected. In this paper, the hfs configuration data is compared with that from the lfs configuration. Preliminary experiments combining lower hybrid current drive and ED operation in the hfs configuration are also reported. (author) 5 refs., 4 figs

  3. Production and control of an edge radiating layer with the ergodic divertor on TORE SUPRA

    International Nuclear Information System (INIS)

    Poutchy, L.; Vallet, J.C.; Michelis, C. de; Grosman, A.; Hess, W.; Mattioli, M.; Monier-Garbet, P.

    1992-01-01

    We have recently defined on Tore Supra a discharge piloting strategy to prevent disruptions at the density limit, based on the property of the Ergodic Divertor to stabilize MHD activity. This strategy allows plasma studies close to the density limit without disruptions, and has been successfully used on Tore Supra ohmicly heated plasmas. The Ergodic Divertor allows also the stabilization of detached plasmas which appear spontaneously near the density limit. Edge impurities are shown to play a fundamental role in this stabilization. Detached plasmas have been thereby controlled during 10 seconds

  4. Connexion topology and sol physics induced by the ergodic divertor in Tore Supra

    International Nuclear Information System (INIS)

    Nguyen, F.; Ghendrih, P.; Samain, A.

    1990-01-01

    The diffuse connexion induced by the ergodic divertor in Tore Supra leads to heat load patterns on the plasma facing components. The topology of those patterns is analysed using field line tracing and analytical derivation of effective heat transport coefficients. Control of the heat load via the magnetic configuration is investigated

  5. Progress in ergodic divertor operation on Tore Supra

    International Nuclear Information System (INIS)

    Ghendrih, Ph.; Becoulet, M.; Colas, L.; Grosman, A.; Guirlet, R.; Gunn, J.; Loarer, T.; Azeroual, A.; Basiuk, V.; Beaumont, B.; Becoulet, A.; Bremond, S.; Bucalossi, J.; Capes, H.; Corre, Y.; Costanzo, L.; Michelis, C. de; Devynck, P.; Feron, S.; Friant, C.; Garbet, X.; Giannella, R.; Grisolia, C.; Hess, W.; Hogan, J.; Ladurelle, L.; Laugier, F.; Martin, G.; Mattioli, M.; Meslin, B.; Monier-Garbet, P.; Moulin, D.; Nguyen, F.; Pascal, J.Y.; Pecquet, A.L.; Pegourie, B.; Reichle, R.; Saint-Laurent, F.; Vallet, J.C.; Zabiego, M.

    1999-09-01

    Upgrade of the Tore ergodic divertor has led to significant progress in ergodic divertor physics. The disruptive limit governed by the stochastization of the outer magnetic surfaces is found to occur for a value of the Chirikov parameter reaching 2 on the magnetic surface q = 2 + 3 / 12. This experimentally observed robustness allows one to operate at very low safety factor on the separatrix (q ∼ 2). Numerical analysis of ballooning turbulence in a stochastic layer indicates that the decay of the density fluctuations is in associated with an increase of the fluctuating electric drift velocity. The bottom line is then an enhanced cross-field transport in the vicinity of the target plates. This lowering of confinement appears to be compensated by an intrinsic transport barrier on the electron temperature. The 3-D response of the temperature field is computed with a fluid code. The intrinsic transport barrier at the separatrix, reported experimentally, can be recovered together with small amplitude temperature modulations in the divertor volume. Experimental evidence of the 3 density regimes (linear, high recycling and detachment) is reported. The low critical density values for these transitions indicate that similar parallel physics govern the axisymmetric and ergodic divertor, despite the open configuration of the latter. Measurement and understanding of these density regimes provide a means for feedback control of plasma density and an improvement in ICRH coupling scenarios. Experimental data also indicated that particle control with the vented target plates is effective. Increase of impurity control and radiation efficiency are recalled. Global power balance has been analysed. These results confirm the enhanced radiation capacity of the ergodic divertor. (author)

  6. Particle recirculation in the ergodic divertor of Tore Supra

    International Nuclear Information System (INIS)

    Gunn, J.P.; Azeoual, A.; Becoulet, M.

    1999-01-01

    The present paper addresses the issue of particle recirculation in discharges where low energy flux to ergodic divertor target plates is achieved, in highly radiating detached ohmic plasmas. Plasma temperature and particle flux are measured by flush-mounted probes in the divertor plates, and by an upstream fast scanning Mach probe. The scalings with core density of the ion flux and electron temperature are well described by the simple two-point model used in axisymmetric poloidal divertors. The detachment signature is a pressure drop that occurs when the edge temperature falls below 10 eV. The parallel ion flux gradient is always positive, indicating that recombination is unlikely to play an important role in detachment. Visible spectroscopy of a neutralizer plate shows that attainment of cold detached plasmas near the density limit coincides with an abrupt increase of fueling for both deuterium and impurities. A feedback algorithm based on real time Langmuir probe measurements has been developed to monitor detachment and avoid disruptions. (authors)

  7. Tore Supra

    International Nuclear Information System (INIS)

    Supra, E.T.

    1989-01-01

    Tore Supra is a tokamak implemented on the site of CEN Cadarache by the EURATOM-CEA Association. The machine technology integrates all problems related to the fabrication and the operation of large cyrogenic superconducting coils and of the associated cryogenic system. Tore Supra will provide a significant experience to prepare the next generation of machines for controlled design. Tore Supra has been designed to implement a lage physics program that takes advantage of the capability of operation with plasma pulses in excess of 30 seconds. Operation started in April, with a toroidal field of 2 teslas. Discharges of 500 kA with a 3 second current flat top were obtained after a few days. Machine parameters will be raised to their nominal values ( B -- 4.5 Teslas and Ip -- 1.7 MA) during summer

  8. Interaction of ICRF power and edge plasma in Tore Supra ergodic divertor configuration

    International Nuclear Information System (INIS)

    Nguyen, F.; Grosman, A.; Basiuk, V.; Fraboulet, D.; Beaumont, B.; Becoulet, A.; Ghendrih, Ph.; Ladurelle, L.; Meslin, B.

    2000-01-01

    The coupling of ICRF power to plasma is a crucial problem in Tore Supra for high power and long pulse operations and depends greatly on the edge parameters, in particular on the edge density. Conversely, the behaviour of the bulk plasma is related to the edge conditions and the injection of RF power also induces major modifications on the edge plasma. Moreover, the Ergodic Divertor (ED) of Tore Supra imposes a complex configuration at the edge due to the presence of the magnetic perturbation. Several diagnostics are available to study the interaction of ICRF power with the edge plasma: Langmuir probes on the ED modules, infra red (IR) cameras, charge exchange neutral analysers. In minority heating scheme, the edge density is very sensitive to any perturbation in the high recycling regime which is always found in the ED configuration for relevant plasma parameters. Partially detached regimes, with or without inhomogeneities of density and temperature induced by the flux tubes of the laminar layer, are obtained for high resistance coupling values. The coupling is then not very robust and feedback control or antenna automatic matching techniques are developed. In fast wave electron heating scheme with ED, various fast wave absorption mechanisms (minority heating, Mode Conversion, Alfven resonance) are present at the plasma edge due to the large size of the plasma. The ICRF coupling is difficult due to the low fast wave direct electron damping, even with high hydrogen minority scheme. An increase of the injected ICRF power could improve this situation

  9. Transport in the plasma edge specific connection to the wall in the Tore Supra ergodic divertor experiments

    International Nuclear Information System (INIS)

    Grosman, A.; Ghendrih, P.; DeMichelis, C.; Monier-Garbet, P.; Vallet, J.C.; Capes, H.; Chatelier, M.; Geraud, A.; Goniche, M.; Grisolia, C.; Guilhem, D.; Harris, G.; Hess, W.; Nguyen, F.; Poutchy, L.; Samain, A.

    1992-01-01

    The ergodic divertor experiments in TORE SUPRA can be analysed along two main lines. The first one refers to the change of the heat and particle transport in the ergodized zone. This is especially true for the electron heat transport which is enhanced in the edge layer. But other distinctive features give evidence of the importance of the parallel connexion length between the plasma edge and the wall. The field lines, which are stochastic in the major part of the perturbed layer (10-15 cm) are such that, in the outermost layer (3 cm), the connexion topology is regular. This has obvious effects on the particle and power deposition, but also on the plasma parameters, and consequently influences the particle recycling and impurity shielding processes. The TORE SUPRA ergodic divertor experiments are reviewed in this framework

  10. Mechanical design and manufacture of magnetic ergodic divertor for the TORE SUPRA tokamak

    International Nuclear Information System (INIS)

    Lipa, M.; Aymar, R.; Deschamps, P.; Hertout, P.; Portafaix, C.; Samain, A.

    1989-01-01

    A configuration of six equally spaced ergodic divertors has been chosen to control the plasma impurities in the TORE SUPRA tokamak since the control of these impurities is essential to the long pulse duration envisioned for the machine. Each of the six indentical modules is composed of (8) conductor bars arranged in a poloidal direction forming a resonant helical winding. The proximity of the conductors to the plasma requires that each copper assembly be water cooled, enclosed in a stainless steel casing and protected by pure graphite tiles attaches to the inner surface of the casing. Particles which drift between the coil bars are neutralized on actively water cooled neutralizer plates and then pumped out by titanium getter pumps which are located on each toroidal end of a divertor modul. (author). 5 refs.; 7 figs.; 1 tab

  11. Particle exhaust with vented structures: application to the ergodic divertor of Tore Supra

    International Nuclear Information System (INIS)

    Azeroual, A.

    2000-01-01

    In a thermonuclear reactor, one must continuously fuel the discharge and extract the ashes resulting from fusion reactions. To avoid the risk of discharge poisoning, α-particle concentration is limited to ∼ 10 %. To allow for steady-state conditions requires then to extract ≥2 % of the helium out flux. In Tore Supra, the ergodic divertor is the main component managing the heat and particle fluxes at the edge. Its principle consists in generating a resonant perturbation able to destroy magnetic surfaces at the plasma periphery. In this region, the field lines are open and connected at both ends to neutralizers which are wetted by the major part of the heat and particle fluxes and are the structures through which a part of the plasma out flux is pumped for maintaining the discharge in steady-state conditions. This work describes the neutral recirculation around the ergodic divertor and is based on a data base of 56 discharges. One discuss the two processes allowing for particle exhaust: the ballistic collection of ions and that of neutrals backscattered by atomic reactions. These two processes are modelled accounting for a realistic description of the divertor geometry. A comparison between simulations and experiments is presented for measurements characterising the three main actors of plasma-wall interaction: the edge plasma, the D α light emission and the neutral pressure in the divertor plenum. Last, one question how such a system can be extrapolated to next step machines, for which one must account for technical constraints linked to the presence of the shield protecting the coils from the high neutron flux. (author)

  12. Plasma density control with ergodic divertor on Tore Supra; Controle de la densite du plasma en presence du divertor ergodique dans le tokamak Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Meslin, B

    1998-04-30

    Plasma density control on the tokamak Tore Supra is important for the optimization of every experimental scenario dealing with the improvement of plasma performances. Specific conditions are required both in the plasma bulk and at the edge. Within the framework of the present study, a magnetic configuration is used in the e plasma edge of Tore Supra: the ergodic divertor configuration. A magnetic perturbation which is resonant with the permanent field destroys the plasma confinement locally, opening the field lines onto the material components. They aim of the study is the characterization of the edge density in every relevant scenario for Tore Supra. The first part of this work is dedicated to density and temperature measurements by a series of fixed Langmuir probes located at the very edge of the plasma. Thanks to them, density regimes have been put in evidence during experiments where the volume averaged density , an usual control parameter of the plasma, was varied. The analysis of heat and particle transport through the plasma edge region explains the mechanisms leading to those regimes. The essential factor in our analysis is the dependence of the electron conductivity and ionization depth on temperature. While heat conduction governs the heat transport, the edge density varies linearly according to . Below a critical temperature, reached when the ion flux amplification at constant power density is large enough, a parallel temperature gradient appears leading to a density gradient in the opposite direction in order to maintain the pressure constant along the field lines. A high recycling regime is obtained and the edge density varies like {sup 3}. The pressure conservation is no more satisfied during the detachment of the plasma, which is characterized by a high neutral density at low temperatures leading to a ion momentum loss by friction against the neutrals. The edge density drops in those conditions. These regimes are similar

  13. Experimental study of the topological aspect of the ergodic divertor in Tore-supra tokamak; Etude experimentale des aspects topologiques du divertor ergodique de Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Costanzo, L

    2001-10-01

    The control of power deposition onto plasma facing components in tokamaks is a determining factor for future thermonuclear fusion reactors. Plasma surface interaction can be performed using limiters or divertors. The ergodic divertor installed on Tore Supra is an atypical example of a magnetic divertor. It consists in applying a magnetic perturbation which establishes a particular topology of the plasma in contact with the wall (edge plasma). We carried out dedicated experiments in order to study parallel heat flux which strike the divertor neutralizers. This quantitative and qualitative analysis of heat flux as a function of experimental conditions allows to determine the profiles of power deposition along the neutralizers. The influence of plasma electron density, additional heating, impurities and injected gas was established. An experimental study of the sheath heat transmission factor {gamma} was carried out by correlating measurements made with Langmuir probes and infrared imaging. This study gave rise to a major conclusion: for ohmic discharges with deuterium injection and most of the time with helium, it was experimentally confirmed that {gamma}=7 in agreement with classical sheath theory. However, an increase of this factor with additional power has been shown. Detached plasma, which is an attractive regime in order to reduce the power deposition, requires an optimized control. A new measurement of the detachment onset has been developed. It is based on the variation of heat flux onto the plates derived from infrared measurements. A detachment cartography with the determination of a new 2D 'IR' Degree of Detachment was carried out allowing to locate the zone where the detachment starts. We can apply this concept both to other tokamaks such as JET and ITER. A comparison between the axisymmetric divertor and the ergodic divertor is also presented concerning the power deposition in the two configurations. Low heat flux with the ergodic divertor is a

  14. Current profile control and magnetohydrodynamic stability in Tore Supra discharges with edge-plasma control by the ergodic divertor

    International Nuclear Information System (INIS)

    Zabiego, M.; Friant, C.; Ghendrih, P.; Becoulet, M.; Bucalossi, J.; Saint-Laurent, F.

    1999-01-01

    Although ergodic divertors are primarily designed to control particle and heat fluxes at the plasma edge, they also happen to affect the MHD stability of tokamak discharges. On Tore Supra, the ergodic divertor has long been known to stabilize the m/n=2/1 tearing mode induced, for instance, by edge radiation and detachment processes, thus allowing safe high-current and high-density operations. More recently, though, in discharges where ergodic divertor operations were optimised relative to the control of the edge-plasma (i.e., with large divertor perturbation), a detrimental increase in the disruptiveness has been observed. The action that the ergodic divertor has on the MHD activity is interpreted in terms of a redistribution of the current profile. The latter results from a large increase in the edge resistivity, primarily induced by the degradation of the electron energy confinement in the ergodic layer. The possibility that a transport barrier develops in the vicinity of the separatrix strongly affects the considered modelling. (authors)

  15. Behaviour of intrinsic carbon and laser blow-off injected nickel in Tore Supra during ergodic divertor activation

    International Nuclear Information System (INIS)

    Mattioli, M.; De Michelis, C.; Monier-Garbet, P.

    1995-01-01

    The behaviour of intrinsic carbon (the dominating impurity) and laser blow-off injected nickel has been studied in Tore Supra during ergodic divertor (ED) activation. The carbon content is reduced in the plasma core as a result of the screening effect of the ergodic layer, which is due to increased transport in the layer, to increased recycling flux and to a modified impurity source term. Simulations of the C VI and C V intensity ratios require in the ergodic edge both an increased diffusion and a large (in the 10 16 -10 17 m -3 range) neutral hydrogen isotope density. The nickel burst is not 'screened' and penetrates into the core plasma. The confinement time τ P of the injected elements is always increased when the ED is activated, but there is no modification of the core plasma transport (diffusion coefficients, convection velocities, central reduced transport region extension). To simulate the increased central τ p values, a peripheral transport barrier has to be introduced. Satisfactory nickel brightness simulations can be obtained by modifying the inward convection velocity and/or the diffusion coefficient. If the barrier is taken to be purely diffusive, satisfactory carbon line ratios can be recovered, but the simulated injected impurity confinement time τ p is too short. For a satisfactory nickel brightness simulation it is necessary to add to the barrier some inward convection, pushing also the intrinsic carbon ions inwards, but this hinders correct line ratio evaluations. (author). 31 refs, 14 figs, 1 tab

  16. Tore Supra: technical description

    International Nuclear Information System (INIS)

    1985-08-01

    This report is aimed, after a brief recall of physics and technologic perspectives of Tore Supra, at giving a detailed description of the basic machine; details of each component are defined. Volume 1 is specifically concerned with the general aspects of Tore Supra and the toroidal field system [fr

  17. Tore Supra: technical description

    International Nuclear Information System (INIS)

    1985-08-01

    Cryogenic system of Tore Supra is described with its principal functions and operation modes. Data control and acquisition with on line data processing is presented. Radiation dose and induced radioactivity evaluation is studied. Cooling system is detailed together with characteristics of facilities and circuits to cool. Then machine assembly and buildings are presented [fr

  18. Ciel, a new breath for Tore Supra

    International Nuclear Information System (INIS)

    Garin, P.

    1998-01-01

    In view of preparing next generation of tokamaks, a new goal has been given to Tore Supra, initially designed for 30 second operation. In order to fulfill this target, with the ultimate aim of injecting in the plasma 25 MW for 1000 s shots: all existing components (including the 6 ergodic divertor modules) present inside the inner vessel of Tore Supra will be removed by the end of 1999, they will be replaced in 2000 by a set of up to date technology components, designed to withstand an overall power of 25 MW for shots up to 1000 s constituting the so-called 'CIEL' project (French acronym for 'Composants Internes Et Limiteur'). It is planned to stop present Tore Supra's operation in autumn 1999, and start again with CIEL environment at the end of 2000. Full capacity (pumping and cooling) will be available in 2002. (author)

  19. Particle exhaust with vented structures: application to the ergodic divertor of Tore Supra; Pompage des particules dans les tokamaks au moyen d'une structure a events: le divertor ergodique de Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Azeroual, A

    2000-04-04

    In a thermonuclear reactor, one must continuously fuel the discharge and extract the ashes resulting from fusion reactions. To avoid the risk of discharge poisoning, {alpha}-particle concentration is limited to {approx} 10 %. To allow for steady-state conditions requires then to extract {>=}2 % of the helium out flux. In Tore Supra, the ergodic divertor is the main component managing the heat and particle fluxes at the edge. Its principle consists in generating a resonant perturbation able to destroy magnetic surfaces at the plasma periphery. In this region, the field lines are open and connected at both ends to neutralizers which are wetted by the major part of the heat and particle fluxes and are the structures through which a part of the plasma out flux is pumped for maintaining the discharge in steady-state conditions. This work describes the neutral recirculation around the ergodic divertor and is based on a data base of 56 discharges. One discuss the two processes allowing for particle exhaust: the ballistic collection of ions and that of neutrals backscattered by atomic reactions. These two processes are modelled accounting for a realistic description of the divertor geometry. A comparison between simulations and experiments is presented for measurements characterising the three main actors of plasma-wall interaction: the edge plasma, the D{sub {alpha}} light emission and the neutral pressure in the divertor plenum. Last, one question how such a system can be extrapolated to next step machines, for which one must account for technical constraints linked to the presence of the shield protecting the coils from the high neutron flux. (author)

  20. Plasma Edge Control in Tore Supra

    International Nuclear Information System (INIS)

    Evans, T.E.; Mioduszewski, P.K.; Foster, C.; Haste, G.; Horton, L.; Grosman, A.; Ghendrih, P.; Chatelier, M.; Capes, H.; Michelis, C. De; Fall, T.; Geraud, A.; Grisolia, C.; Guilhem, D.; Hutter, T.

    1990-01-01

    TORE SUPRA is a large superconducting tokamak designed for sustaining long inductive pulses (t∼ 30 s). In particular, all the first wall components have been designed for steady-state heat and particle exhaust, particle injection, and additional heating. In addition to these technological assets, a strict control of the plasma-wall interactions is required. This has been done at low power: experiments with ohmic heating have been mainly devoted to the pump limiter, ergodic divertor and pellet injection experiments. Some specific problems arising in large tokamaks are encountered; the pump limiter and the ergodic divertor yield the expected effects on the plasma edge. The effects on the bulk are discussed

  1. Particles pumping in Tore Supra

    International Nuclear Information System (INIS)

    Bonnel, P.; Chappuis, P.; Lipa, M.

    1989-01-01

    TORE SUPRA and its peripheral equipments are provided with routine clean high vacuum by turbomolecular pumping. During plasma discharges large quantity of very hot gases activating at plasma edge and plasma density in scrape off layer has to be controlled before they strike violently solid wall provoking increase in impurities content and make density up to disruptive level. A Magnetic Ergodic Divertor made of six winding structures - MED - six Vertical Pumped Limiters - VPL - and one Horizontal Pumped Limiter - HPL - are set in the vacuum chamber in order to cope with plasma-wall interactions and neutral gas recycling. Each apparatus is equipped at front side with thermal shield respectively made of polycristallin and pyrolitic graphite bolted on stainless steel support for MED and HPL whereas for VPL it is made of CFC Aerolor 05 brazed on hardened copper. The total heat removal capacity of these plasma facing components is 12 MW. Design of particles collection openings and ducts conductance allow 10% of capture efficiency, that means for TORE SUPRA a flux of 3 x 10 21 particles/second has to be sorbed by water cooled titanium getter pumps, settled at rear side. All those facilities were put into plasma operation at the beginning of 1989 for a short time. Preliminary observations go along with theoretical predictions, that actions in scrappe-off layer may provoke effects in bulk plasma. Very first results drawn out, show that particle collection and heat removal were effective by MED, VPL and HPL and that plasma behaviour was not disturbed by their presence and actions but instead tendency to improvement was observed

  2. Snake studies on Tore Supra

    International Nuclear Information System (INIS)

    Cristofani, P.; Desgranges, C.; Garbet, X.; Geraud, A.; Gil, C.; Hoang, G.T.; Joffrin, E.; Pecquet, A.L.

    1995-01-01

    Snakes have been achieved after pellet injection in Tore Supra during ohmic as well as ICRH discharges as it has already been observed in other machines. On Tore Supra, high speed H 2 pellets were injected into D 2 plasmas under the specified experimental conditions, the matter is deposited in the centre and snakes are produced in 50% of the cases, but they are created on a second much more internal q=1 surface leading probably to a non monotonic current profile. The properties of the snake, induced current modification and the important role of the bootstrap current in the snake formation are described. (K.A.) 5 refs.; 7 figs

  3. First pump limiter experiments in Tore Supra

    International Nuclear Information System (INIS)

    Chatelier, M.; Bruneau, J.L.; Chappuis, P.; Gil, C.; Guilhem, D.; Lipa, M.; Rodriguez, L.; Vallet, J.C.; Van Houtte, D.; Watkins, J.G.

    1989-01-01

    The thermal load and the particle pumping effects on the outboard pump limiters (OPL), in Tore Supra are analyzed. The investigations are performed for the plasma either in contact with the OPL/ONPL (outboard non pumped limiters) alone or with the OPL and the vertical limiters together. Calorimetric measurements provide estimates of the time-integrated balance of the energy flow at the plasma edge. Radiated and charge exchange energy losses are deduced from the inner vessel calorimetry (R=242cm, a=94cm). Conductive/convective losses on the OPL and vertical (top and bottom) limiters are independently measured, as well as the integrated energy flow on the ergodic divertors. The calorimetric results, the bolometric measurements of the radiated power and the Ohmic power estimates, are indicated. The central line density from interferometric measurement for the two successive shots, with the ONPL and with the OPL, are given

  4. Tore supra first wall conditioning

    International Nuclear Information System (INIS)

    Gauthier, E.; Achard, M.H.; Grosman, A.; Monier, P.

    1989-01-01

    The procedures and the results obtained concerning impurity and isotopic control in Tore Supra tokamak are summarized. The conditioning of the vessel, mainly achieved by glow discharges, is described. The impurity control of the discharge was monitored with a VUV-X spectrometer. The in situ blasting degassing procedure applied is explained. In the sequence of the conditioning process, the hydrogen and the helium glow discharges and the carbonization method are discussed. The He glow discharges allowed to limit the H content of the He plasma shot below 20%

  5. Disruption mitigation on Tore Supra

    International Nuclear Information System (INIS)

    Martin, G.; Sourd, F.; Saint-Laurent, F.; Bucalossi, J.; Eriksson, L.G.

    2005-01-01

    During disruptions, the plasma energy is lost on the first wall within 1 ms, forces up to hundred tons are applied to the structures and kA of electrons are accelerated up to 50 MeV (runaway electrons). Already sources of concern in present day tokamaks, extrapolation to ITER shows the necessity of mitigation procedures, to avoid serious damages to in-vessel components. Massive gas injection was proposed, and encouraging tests have been done on Textor and DIII-D. Similar experiments where performed on Tore Supra, with the goal to validate their effect on runaway electrons, observed during the majority of disruptions. 0.1 mole of helium was injected within 5 ms in ohmic plasmas, up to 1.2 MA, either stable, or in a pre-disruptive phase (argon puffing). Beneficial effects where obtained: reduction of the current fall rate and eddy currents, total disappearance of runaway electrons and easy recovery for the next pulse, without noticeable helium pollution of following plasmas. Analysis of the 4 ms period between injection and disruption indicates that to reach these goals, one need to inject enough helium to keep it only partially ionised. It correspond to 0.1 g for Tore Supra, and extrapolate to hundred's of grams for ITER. (author)

  6. Disruption mitigation on Tore Supra

    International Nuclear Information System (INIS)

    Martin, G.; Sourd, F.; Saint-Laurent, F.; Bucalossi, J.; Eriksson, L.G.

    2004-01-01

    During disruptions, the plasma energy is lost on the first wall within 1 ms, forces up to hundred tons are applied to the structures and kA of electrons are accelerated up to 50 MeV (runaway electrons). Already sources of concern in present day tokamaks, extrapolation to ITER shows the necessity of mitigation procedures, to avoid serious damages to in-vessel components. Massive gas injection was proposed, and encouraging tests have been done on Textor and DIII-D. Similar experiments where performed on Tore Supra, with the goal to validate their effect on runaway electrons, observed during the majority of disruptions. 0.1 mole of helium was injected within 5 ms in ohmic plasmas, up to 1.2 MA, either stable, or in a pre-disruptive phase (argon puffing). Beneficial effects where obtained: reduction of the current fall rate and eddy currents, total disappearance of runaway electrons and easy recovery for the next pulse, without noticeable helium pollution of following plasmas. Analysis of the 4 ms period between injection and disruption indicates that to reach these goals, one need to inject enough helium to keep it only partially ionised. It corresponds to 0.1 g for Tore Supra, and extrapolate to hundreds of grams for ITER. (authors)

  7. Tore Supra: technical aspects and early results after one year of operation

    International Nuclear Information System (INIS)

    Gravier, R.

    1989-01-01

    After one year operation (1988 to 1989), technical aspects of component systems and equipment of Tore Supra are summarized. Particular attention is given to the operation with: supraconducting toroidal field coil system, cryogenic system, poloidal field system, in vessel equipment, first wall conditioning, pump limiter. The ergodic divertor experiments and the current drive experiment are reported. The plasma heating methods adopted in Tore Supra are presented

  8. Particle control studies on Tore Supra

    International Nuclear Information System (INIS)

    Mioduszewski, P.

    1987-01-01

    The report consists of viewgraphs. The goal of the particle control program at Tore Supra is to study plasma performance with strong pellet fueling and corresponding particle exhaust in a limiter tokamak

  9. Pellet injection requirements for TORE SUPRA

    International Nuclear Information System (INIS)

    Lafferranderie, J.

    1986-01-01

    The main parameters of TORE SUPRA are outlined and pellet injection requirements to meet plasma density goals are discussed. Topics considered include plasma buildup, plasma refueling and penetration depth

  10. Fast imaging system on Tore Supra

    International Nuclear Information System (INIS)

    Geraud, A.; Salasca, S.; Verger, J. M.; Alarcon, T.; Agarici, G.; Bremond, S.; Chenevois, J. P.; Geynet, M.; Migozzi, J. B.; Reux, C.

    2009-01-01

    A new endoscope aiming at transferring the image of a poloidal section of the Tore Supra plasma to a fast camera able to record frames at a speed up to 4800 frames per second at full resolution, or much faster for a limited number of pixel, has been installed on Tore Supra. First movies showing the light emission associated to fast phenomena such as plasma start up, disruptions or gas and pellet injections have been produced.

  11. Edge plasma diagnostics on Tore Supra tokamak

    International Nuclear Information System (INIS)

    Fujita, Junji

    1991-01-01

    From 1988 to 1991, the international scientific research 'Diagnosis of peripheral plasma in Tore Supra tokamak' was carried out as a three-year plan receiving the support of the scientific research expense of the Ministry of Education. This is to apply the method of measuring electron density distribution by neutral lithium beam probe spectroscopy to the measurement of the electron density distribution in the peripheral plasma in Tore Supra Tokamak in France. Among many tokamaks in operation doing respective characteristics researches, the Tore Supra generates the toroidal magnetic field by using superconducting coils, and aims at the long time discharge for 30 sec. for the time being, and for 300 sec. in future. In the plasma generators for long time discharge like this, the technology of particle control is a large problem. For this purpose, a divertor was added to the Tore Supra. In order to advance the research on particle control, it is necessary to examine the behavior of plasma in the peripheral part in detail. The measurement of peripheral plasma in tokamaks, beam probe spectroscopy, the Tore Supra tokamak, the progress of the joint research, the problems in the joint research and the perspective of hereafter are reported. (K.I.)

  12. Nuclear fusion TORE SUPRA, a new stage

    International Nuclear Information System (INIS)

    Gregoire, M.; Laurent, L.

    1995-01-01

    Since almost forty years, the scientists try and neutralize in a pacific aim thermonuclear fusion energy and therefore they use the magnetic confinement of hot plasmas.In France, since 1960 the achieved studies permitted in 1988 to bring into service the TORE SUPRA TOKAMAK, which used, for the first time a superconducting magnet to generate the confinement magnetic field. TORE SUPRA, which didn't still explore its maximal potentialities, will be one of the apparatuses which will be used as basis of the international project ITER development. 5 figs

  13. Remote experiment participation on Tore-Supra

    International Nuclear Information System (INIS)

    Theis, J.-M.; Larsen, J.-M.

    2004-01-01

    The DRFC has traditionally had a very large external collaboration involvement. In particular, 15% of the DRFC work is directed towards the JET programme. As a consequence substantial telecommunications facilities have been installed [F.E.D. 60/3 (2002) 449; F.E.D. 60/3 (2002) 459]. A specific station for remote communication has been set up in the Tore-Supra control room, closely coupled to a collaborating team at INRS Que., Canada. This paper describes our pilot experience with the Canadian participation, which gives details of the communication and data sharing tools used to fully work on Tore-Supra

  14. Matching of Tore Supra ICRH antennas

    International Nuclear Information System (INIS)

    Ladurelle, L.; Beaumont, B.; Kuus, H.; Lombard, G.

    1994-01-01

    An automatic matching method is described for Tore Supra ICRH antennas based on impedance variations seen at their feed points. Error signals derived from directional voltage and phase measurements in the feeder allow to control the matching capacitors values for optimal power transmission. (author) 5 refs.; 9 figs

  15. Net erosion measurements on plasma facing components of Tore Supra

    International Nuclear Information System (INIS)

    Tsitrone, E.; Chappuis, P.; Corre, Y.; Gauthier, E.; Grosman, A.; Pascal, J.Y.

    2001-01-01

    Erosion of the plasma facing components is a crucial point of investigation in long pulse operation of future fusion devices. Therefore erosion measurements have been undertaken in the Tore Supra tokamak. After each experimental campaign, different plasma facing components have been monitored in situ by non-destructive means, in order to evaluate their net erosion following a long plasma exposure. This paper presents the results obtained over three experimental campaigns on the Tore Supra ergodic divertor B 4 C-coated neutralisers and CFC Langmuir probes. The erosion on the Langmuir probes after one year of plasma exposure can reach 100 μm, leading to an effective erosion coefficient of around 5x10 -3 to 10 -2 , in reasonable agreement with values found on other tokamaks. The erosion of the ergodic divertor neutraliser plates is lower (10 μm). This is coherent with the attenuated particle flux due to a lower incidence angle, and might also be due to some surface temperature effect, since the neutralisers are actively cooled while the Langmuir probes are not. Moreover, the profile along the neutraliser shows net erosion in zones wetted by the plasma and net redeposition in shadowed zones

  16. Steady-State Operation in Tore Supra

    Science.gov (United States)

    Hoang, G. T.; Tore Supra, Equipe

    1999-11-01

    The Tore Supra superconducting tokamak is devoted to steady-state operation. The CIEL (French acronym for internal component and limiter) project( LIPA, M., et al., Proc. of the 17th IEEE/NPSS Symp. on Fus. Engineering, San Diego, USA, 1997.) consists of a complete upgrade of the inner chamber of Tore Supra, planned to be installed during the year 2000. This project will allow physics scenarios with up to 24 MW of radio frequency heating and current drive (typically 8 - 10 MW of ICRF, 10 - 12 MW of LHCD and 2 MW of ECRF) in stationary plasmas up to 1000 s, with active particle control. This paper presents an overview of the experiments planned to explore the properties, such as the confinement and MHD stability, of various heating and current drive scenarios for long duration discharges. The expected performance for the CIEL phase is also reported.

  17. Fusion profile measurement on Tore-Supra

    International Nuclear Information System (INIS)

    Martin, G.; Gilles, P.; Joyer, P.

    1990-01-01

    The new diagnostic set on Tore-Supra to observe charged fusion particles is described. The detector is a multiple strip chips and equivalent to 16 small detectors placed close to one another. For given toroidal and poloidal fields, the knowledge of the pitch angle allows to calculate the particle trajectories. The proton flux on the detector is the highest for the most central trajectory. The detector efficiency, resolution and first experimental results are discussed

  18. TORE SUPRA vacuum vessel and shield manufacturing

    International Nuclear Information System (INIS)

    Blateyron, J.; Lepez, R.

    1984-01-01

    TORE SUPRA vacuum vessel and vacuum chamber shield manufacturing in progress at Jeumont-Schneider consists of three main phases: - Detail engineering and manufacturing fixture construction; - Prototype section manufacturing and process preparation; - Construction of the 6 production modules. The welding techniques adopted, call for three special automatic processes: TIG, MIG and PLASMA welding which guarantee mechanical strength, vacuum tightness and absence of distortion. Production of the modules began July 1984. (author)

  19. Long pulse operation on Tore Supra

    International Nuclear Information System (INIS)

    Monier-Garbet, P.

    2004-01-01

    This document gathers a series of transparencies dedicated to the long pulse operation on Tore-Supra. The structure of the document is described as follows: the first part is an introduction recalling fusion basis and presenting the different physical and technological phenomenon time scales. The second part is dedicated to the production of long pulses through non-inductive drive and some experimental scenarios illustrate it. The final part is devoted to physics issues like particle retention

  20. Electron cyclotron emission measurement in Tore Supra

    International Nuclear Information System (INIS)

    Javon, C.

    1991-06-01

    Electron cyclotron radiation from Tore-Supra is measured with Michelson and Fabry-Perot interferometers. Calibration methods, essential for this diagnostic, are developed allowing the determination of electron temperature in the plasma. In particular the feasibility of Fabry-Perot interferometer calibration by an original method is demonstrated. A simulation code is developed for modelling non-thermal electron population in these discharges using measurements in non-inductive current generation regime [fr

  1. TORE SUPRA fast reciprocating radio frequency probe

    International Nuclear Information System (INIS)

    Thomas, C.E. Jr.; Harris, J.H.; Haste, G.R.; Kwon, M.; Goulding, R.H.; Hoffman, D.J.; Saoutic, B.; Becoulet, A.; Fraboulet, D.; Beaumont, B.; Kuus, H.; Ladurelle, L.; Pascal, J.Y.

    1995-01-01

    A fast reciprocating ion cyclotron range of frequencies (ICRF) probe was installed and operated on TORE SUPRA during 1992/1993. The body of the probe was originally used on the ATF experiment at Oak Ridge National Laboratory. The probe was adapted for use on TORE SUPRA, and mounted on one of the two fast reciprocating probe mounts. The probe consists of two orthogonal single-turn wire loops, mounted so that one loop senses toroidal rf magnetic fields and the other senses poloidal rf magnetic fields. The probe began operation in June, 1993. The probe active area is approximately 5 cm long by 2 cm, and the reciprocating mount has a slow stroke (5 cm/s) of 30 cm and a fast stroke (1.5 m/s) of about 10 cm. The probe was operated at distances from the plasma edge ranging from 30 to -5 cm (i.e., inside the last closed flux surface). The probe design, electronics, calibration, data acquisition, and data processing are discussed. First data from the probe are presented as a function of ICRF power, distance from the plasma, loop orientation, and other plasma parameters. Initial data show parametric instabilities do not play an important role for ICRF in the TORE SUPRA edge and scrape-off-layer (SOL) plasmas. Additionally it is observed that the probe signal has little or no dependence on position in the SOL/plasma edge

  2. Global analysis of ICRF wave coupling on Tore Supra

    International Nuclear Information System (INIS)

    Goniche, M.; Bremond, S.; Colas, L.

    2003-01-01

    The Tore Supra tokamak is equipped with a multi-megawatt ion cyclotron range of frequency (ICRF) system for heating and current drive. The coupling of the fast wave to the plasma, characterized by the distributed coupling resistance along the radiating straps, is a crucial issue in order to launch large RF powers. Many factors can have an effect on ICRF wave coupling. Quantitative prediction from theoretical modelling requires the knowledge of the local inhomogeneous plasma density profile in front of the antenna for running sophisticated antenna codes. In this work, we have rather followed a 'global' approach, based on Tore Supra experimental results, for the parametric study of the coupling resistance. From a large data base covering seven experimental campaigns (∼2250 shots), a scaling law of the coupling resistance including the main parameters of the plasma and of the antenna configuration is established. This approach is found to be reliable for the analysis of coupling in the different scenarios: He/D 2 gas filling, gas/pellets for plasma fuelling, plasma leaning on inner wall/low field side limiter, limiter/ergodic divertor configuration, minority heating/direct electron heating. From one scenario to another, a significant variation of the coefficients of the scaling law is found. The study of these variations allows to get some insight on the main physical mechanisms which influence the ICRF wave coupling in a tokamak operation, such as the wall conditioning and recycling conditions, RF sheaths or frequency. (author)

  3. Recent results on Tore Supra

    International Nuclear Information System (INIS)

    Moreau, D.

    1995-01-01

    Recent results regarding heating, confinement, current drive and profile modifications, heat and particle exhaust are reported. Improved core confinement is obtained after pellet injection (PEP) or Lower Hybrid current drive (LHEP) and may be linked with small - or reversed - central magnetic shear. Conversely, by increasing the magnetic shear in the gradient region, both LHCD and fast wave electron heating (FWEH) have produced improved global confinement was carried by the bootstrap current. Fast wave current drive has been observed at the level of 80 kA in a 0.4 MA discharge. In the ergodic divertor configuration, stable radiative layers were obtained with neon injection. At least 80% of a total of 7 MW injected power were radiated without confinement degradation or impurity accumulation. Finally, the heat exhaust capability of the various actively cooled plasma facing components is briefly described. (author) 14 refs.; 13 figs

  4. The acquisition system for Tore Supra 1000 s discharges

    International Nuclear Information System (INIS)

    Guillerminet, B.; How, J.

    2000-01-01

    Long duration discharges are planned for Tore Supra in the near future. A study has been made to detect and correct all the possible limitations of the data acquisition system. Results and analysis of a few 1000 s 'dry-run' test pulses are presented in this paper as well as the solutions foreseen for Tore Supra

  5. The TORE SUPRA fast reciprocating RF probe

    International Nuclear Information System (INIS)

    Thomas, C.E. Jr.; Harris, J.H.; Haste, G.R.

    1994-01-01

    A fast reciprocating ICRF (Ion Cyclotron Range of Frequencies) probe was installed and operated on TORE SUPRA during 1992/1993. The body of the probe was originally used on the ATF experiment at ORNL. The probe was adapted for use on TORE SUPRA, and mounted on one of the two fast reciprocating probe mounts. The probe consists of two orthogonal single-turn wire loops, mounted so that one loop senses toroidal RF magnetic fields and the other senses poloidal RF magnetic fields. The probe began operation in June, 1993. The probe active area is approximately 5 cm long by 2 cm, and the reciprocating mount has a slow stroke (5 cm/sec) of 30 cm by 2 cm, and the reciprocating mount has a slow stroke (5 cm/sec) of 30 cm and a fast stroke (1.5 m/sec) of about 10 cm. The probe was operated at distances from the plasma edge ranging from 30 cm to -5 cm (i.e., inside the last closed flux surface). The probe design, electronics, calibration, data acquisition and data processing are discussed. First data from the probe are presented as a function of ICRF power, distance from the plasma, loop orientation, and other plasma parameters. Initial data shows parametric instabilities do not play an important role for ICRF in the TORE SUPRA edge and scrape-off-layer (SOL) plasmas. Additionally it is observed that the probe signal has little or no dependence on position in the SOL/plasma edge

  6. Pump limiter studies in Tore Supra

    International Nuclear Information System (INIS)

    Chatelier, M.; Bonnel, P.; Bruneau, J.L.; Gil, C.; Grisolia, C.; Loarer, T.; Martin, G.; Pegourie, B.; Rodriguez, L.

    1991-01-01

    The aim of the Tore Supra pump limiter program is to study particle exhaust with a pump limiter system in long-pulse discharges with continuous pellet fueling and strong auxiliary heating. The pump limiter system consists of six vertical modules, located at the bottom of the machine, and one horizontal module at the outer midplane. The instrumentation of the limiter included pressure gauges, a residual gas analyser Langmuir probes, a spectrometer and water calorimeters. Initial results in low-density discharges, with the outboard limiter only, showed a modest effect on the plasma density, while large exhaust fluxes were measured in the pump limiter, without any external fueling

  7. One minute pulse operation in TORE SUPRA

    International Nuclear Information System (INIS)

    van Houtte, D.

    1992-01-01

    Long pulse operation is the main focus of the research program on the high field superconducting Tore Supra tokamak. During the past two years, most of subsystems (Lower Hybrid Current Drive, Ion Cyclotron Radiofrequency Heating, Pellet Injector, Inner Wall, Pump Limiters) have been tested separately and time constants of associated phenomena have been investigated. In 1992, combined experiments have allowed to perform a 1MA-1mn long flat top current plasma discharge. The present paper concentrates on the main characteristics of this long pulse high energy discharge

  8. Ripple losses during ICRF heating in Tore Supra

    International Nuclear Information System (INIS)

    Basiuk, V.; Eriksson, L.-G.; Bergeaud, V.; Chantant, M.; Martin, G.; Nguyen, F.; Reichle, R.; Vallet, J.C.; Delpeche, L.; Surle, F.

    2004-01-01

    The toroidal field coils in Tore Supra are supra-conducting, and their number is restricted to 18. As a result, the ripple is fairly large, about 7% at the plasma boundary. Tore Supra has consequently been equipped with dedicated ripple loss diagnostics, which has allowed ripple loss studies. This paper reports on the measurements made with these diagnostics and provides an analysis of the experimental results, comparing them with theoretical expectations whenever possible. Furthermore, the main heating source accelerating ions in Tore Supra is ion cyclotron resonance range of frequency (ICRF) heating, and the paper provides new information on the ripple losses of ICRF accelerated ions. (author)

  9. Snake studies on TORE-SUPRA

    International Nuclear Information System (INIS)

    Cristofani, P.; Desgranges, C.; Garbet, X.; Geraud, A.; Gil, C.; Hoang, G.T.; Joffrin, E.; Pecquet, A.L.

    1994-01-01

    Snakes have been achieved after pellet injection in TORE-SUPRA during ohmic as well as ICRH discharges as it has already been observed in other machines. They are usually localized on a region around the q=1 surface, and correspond mainly to a perturbation of the density profile. The formation of the snake depends on the penetration depth L p of the pellet: the maximum of ablation must be well inside the q=1 surface, this condition is necessary but not sufficient to produce snakes. For example on TORE-SUPRA high speed H 2 pellets (1500 m/s and approximately 10 21 atoms) were injected into D 2 plasmas with following parameters: I p =1.4 MA, B Φ =3 T, T e =1.7 KeV, e >=2-3 10 19 m -3 , a=0.78 m, R=2.4 m, and q a =3.3. In such experimental conditions, the matter is deposited in the centre and snakes are produced in 50% of the cases, but they are created on a second much more internal q=1 surface leading probably to a non monotonic current profile. The first two paragraphs describe the properties of the snake and the induced current modification. The latter paragraph discusses the important role of the bootstrap current in the snake formation. (author) 5 refs., 7 figs

  10. Runaway electrons dynamics and confinement in Tore-Supra

    International Nuclear Information System (INIS)

    Chatelier, M.; Geraud, A.; Joyer, P.; Martin, G.; Rax, J.M.

    1989-01-01

    The lack of energy of runaway electrons, confined in Tore Supra tokamak, is studied. Ohmic discharges, obtained with helium gas, exhibit a small amount of runaway electrons on both hard X-ray monitors and neutron sensors. The observations show an important lack of energy for runaway electrons confined in Tore Supra. It is assumed to be dued to a small pitch-angle scattering (a few degrees), and many candidates for this are compared: the strongest known one collisions seems not to be enough by an order of magnitude. Density and magnetic scans on Tore Supra are needed to discriminate between enhanced collisional scattering processes and purely magnetic phenomena

  11. Power deposition to the facing components in Tore-Supra

    International Nuclear Information System (INIS)

    Guilhem, D.; Chatelier, M.; Chappuis, P.; Koski, J.; Watkins, J.

    1990-01-01

    The modifications of the power scrape-off length, λ q and power deposition are studied for various configurations in ohmic Tore-Supra plasmas. The plasma is either touching the horizontal limiter alone, the full set of six pump limiters or the inner bumper limiter. All configurations are with and without the ergodic divertor system energized. From a comparison of the infrared images of the limiter we derived that the λ q for power deposition was slightly less than 9±1 mm in ohmic plasmas which is in agreement with the predicted design value of 10 mm. Using the six limiters, instead of one, does not modify λ q significantly, but leads to small asymmetries. The power is shared by all the limiters and the maximum surface temperature on the horizontal limiter decreases. These λ q values have been independently determined by calorimetric measurements on the integrated energy deposition on the horizontal limiter and other internal structures 5 cm into the scrape-off layer. These values agree with the infrared measurements in the two cases. In the presence of the ergodic divertor we observe a broadening of the scrape-off layer, the e-folding length for power deposition reaching 2.5 cm. Large asymmetries in the power deposition can be seen on the front face of the limiter, leading to the formation of hot spots at the leading edges. (orig.)

  12. Power deposition to the facing components in Tore-Supra

    International Nuclear Information System (INIS)

    Guilhem, D.; Chatelier, M.; Chappuis, P.

    1990-01-01

    The modification of power scrape-off-length, λq, and power deposition are studied during various configurations in ohmic TORE-SUPRA plasmas. The plasma is either leaning on the horizontal limiter alone, on the full set of 6 pump limiters or on the inner bumper limiter, all configurations with and without the ergodic divertor system energised. From comparison of the infrared images of the limiter we derived that the λq for power deposition was slightly less than 9 mm (±1 mm) in ohmic plasma which is in agreement with the predicted design value of 10 mm. Inserting the 6 limiters, instead of 1, does not modify significantly λq, but lead to small asymmetries. The power is shared by all the limiters and the maximum surface temperature on the horizontal limiter decreased. These λq values have been independently determined by calorimetric measurements done on the integrated energy deposition on the horizontal limiter and other internal structures 5 cm into the scrape-off layer. These values agree with the infrared measurements in the two cases. In the presence of the ergodic divertor we observe a broadening of the scrape off layer, the e-folding length for power deposition reaching 2.5 cm. Large asymmetries on power deposition can be seen on the front face of the limiter leading to the formation of hot spots at the leading edges

  13. Radiant heat exchange measurements for Tore Supra

    International Nuclear Information System (INIS)

    Chatain, D.; Disdier, F.; Gauthier, A.; Raffin, M.; Renaud, M.

    1984-03-01

    In order to minimize the energy consumption of the low temperature cryogenic system connected to the superconducting magnet of TORE-SUPRA, heat exchange from thermal radiation between the vacuum vessels and the thermal shields has been studied. Accordingly large scale cold and hot walls of T.S. have been simulated in a model with reduced dimensions. In this model, the experiment consists in the measurement of the thermal radiated power between two concentric cylindrical surfaces of stainless steel under vacuum conditions. The temperature of the external cylinder was kept constant at 80 K. The internal cylinder was bakeable up to 250 0 C. Various surface treatments were applied on the two cylinders (mechanical polishing and metal deposition of Al, Ag, Ni) [fr

  14. Global energy confinement in TORE SUPRA

    International Nuclear Information System (INIS)

    Hoang, G.T.; Bizarro, J.P.; Genile, B. de; Hutter, Th.; Laurent, L.; Litaudon, X.; Moreau, D.; Peysson, Y.; Tonon, G.; Houtte, D. van

    1992-01-01

    The global energy confinement behaviour of mixed Ohmic/Lower Hybrid driven Tore Supra plasmas has been analysed at various densities. In contradiction with L-mode ITER scaling law, this analysis indicates that the global energy confinement time depends strongly on the plasma density and the isotopic dependence seems not to be observed. The thermal electron energy content of steady-state discharges is in good agreement with the offset linear Rebut-Lallia scaling law. During current ramp experiments, the global energy confinement time was found to depend on the internal self-inductance (li). Improved confinement has been obtained for a steady-state 0.8 MA plasma where the plasma current profile is peaked by LH waves (li ∼1.8). In this case, the global confinement time is found to be about 40% higher than the value predicted by the Rebut-Lallia scaling law. (author) 3 refs., 6 figs

  15. Gas puff modulation experiments in Tore Supra

    International Nuclear Information System (INIS)

    Haas, J.C.M. de; Devynck, P.; Dudok de Wit, T.; Garbet, X.; Gil, C.; Harris, G.; Laviron, C.; Martin, G.

    1993-01-01

    Experiments with a modulation of the gas puff have been done in Tore Supra with the aim to investigate the transport of particles and heat. The target plasma is ohmically heated, sawtoothing with frequencies between 12 and 20 Hz, deuterium for both the plasma and the injection, and with various densities, rising in a series of shots. Both the diffusion coefficient and the pinch velocity for the particle transport were determined using an harmonic modulation. The method gives reasonable results, even for small perturbations, and the obtained values are able to reproduce the stationary values. The heat flow carried by electrons also shows a modulation. The part of the modulation which is not caused by the density can in principle be used to discriminate diffusive and convective terms in the heat flux. An ion temperature profile calculated with empirically determined value of heat diffusivity reproduces the slow evolution of the total kinetic energy. 6 figs., 7 refs

  16. First ECRH modulation experiments in Tore Supra

    International Nuclear Information System (INIS)

    Zou, X.L.; Artaud, J. F.; Bouquey, F.; Clary, J.; Darbos, C.; Giruzzi, G.; Lennholm, M.; Magne, R.; Segui, J.L.

    2003-01-01

    The modulation of Electron Cyclotron Resonance Heating (ECRH) is a powerful tool to investigate the crucial problem of heat transport in tokamaks. This method consists in producing perturbations in the electron temperature by means of highly localised electron heating. By studying the propagation of the heat pulse associated with such perturbations, it is possible to determine both the heat transport coefficient and, as a by-product, the ECRH power deposition. In this work, three methods have been used for electron transport analysis: i) the well-known FFT method; ii) an analytical method, consisting in the simulation of the temperature modulation by an analytical solution of the heat transport equation in cylindrical geometry; iii) the power balance method with the profile analysis. The three methods are applied to the analysis of recent experiments performed on Tore Supra, and their advantages and drawbacks are discussed. (authors)

  17. Effect of limiter recycling on measured poloidal impurity emission profiles in Tore Supra

    International Nuclear Information System (INIS)

    Hogan, J.; DeMichelis, C.; Monier-Garbet, P.; Becoulet, M.; Bush, C.; Ghendrih, P.; Guirlet, R.; Hess, W.; Mattioli, M.; Vallet, J.C.

    2001-01-01

    Poloidal impurity emission profiles measured with the Tore Supra grazing incidence duochromator exhibit a complex spatial structure during ergodic divertor operation with an outboard poloidal guard limiter. As previous measurements with inboard-wall limited plasmas have shown that these profiles give important information about the ergodic field structure, so the contribution of local neon recycling from the limiter-induced plume has been modeled. This permits a discrimination of edge and core transport effects. The BBQ 3D scrape-off layer code calculates the asymmetric contribution to the emission and MIST 1D simulation gives the symmetric part. A systematic increase is observed in the decay rate of neon emission after injection as the ergodic divertor strength is increased. The calculations permit identification of the limiter plume contribution to the profile structure, and, with this identification, the effect of the divertor to enhance impurity efflux can be seen from the decay data

  18. Thomson scattering upgrade on Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Leroux, F., E-mail: fabrice.leroux@cea.f [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Manenc, L.; Moreau, M. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)

    2010-07-15

    The Thomson scattering diagnostic supplies the electron temperature and density of Tore Supra plasmas from the spectrum analysis of scattered light of a very short laser pulse. A new spectrometer has been realized to improve the signal to noise ratio. In order to obtain an efficient noise reduction, a real time calculation is necessary. The current analogue integration of the signal is inadequate. A fast digitalization must be used with a sampling rate of 1 GSamples/s, a bandwidth of 150 MHz and a 12 bits dynamic range. In a first step, fast analogue data acquisition boards for 4 channels were added in 2009 to the VME acquisition system in place. A MATACQ (Matrix for acquisition) board was chosen for sampling analogue data up to 2 GSamples/s over 4 channels with a large bandwidth of 300 MHz and a 14 bits dynamic range. This solution offers a low cost acquisition system that is not available in any other commercial board with this dynamic range. The first results will be obtained on calibration period with a light emitted diode before the summer 2009. This article will present the new data acquisition system and the coming first results.

  19. First pump limiter experiments in TORE SUPRA

    International Nuclear Information System (INIS)

    Chatelier, M.; Klepper, C.C.; Bruneau, J.L.; Chappuis, P.; Gil, C.; Guilhem, D.; Lipa, M.; Rodriguez, L.; Vallet, J.C.; Van Houtte, D.; Watkins, J.G.

    1989-01-01

    The operation of TORE SUPRA at full power (25MW, 30s) has led to the design of a full set of actively pumped carbon limiters to remove at least 8MW and to partially control the particle balance. An interim version is now installed, composed of 5 vertical and one horizontal outboard (OPL) pump limiters, semi-inertially water cooled. The latter is a result of a collaboration between the US DOE and the Association EUR-CEA, it is fully instrumented and therefore can serve as a reference for the final design. Ohmic discharges (1.85T, 740kA, 8.5s) in helium have been used to test the thermal load on and the particle exhaust efficiency of the OPL. In these experiments the plasma is formed on the inner wall (R = 232 cm, a = 76 cm) and subsequently displaced (6 cm) outward, early on the current plateau, to lean on the OPL (R = 238 cm, a = 75 cm). In addition to the limiters above, a non-pumped outboard (ONLP) limiter of identical shape to the OPL served to produce similar discharges for better comparison and determination of particle control. A comparison is made hereafter of the thermal load and particle pumping effects on the OPL when the plasma is in contact either with the OPL/ONPL alone or with the OPL and the vertical limiters together. 3 refs., 1 fig., 2 tabs

  20. Visible Imaging Diagnostic on Tore-Supra

    Energy Technology Data Exchange (ETDEWEB)

    Dachicourt, R.; Monier Garbet, P.; Beaute, A.; Habib-Naiim, M. [Association Euratom-CEA, CEA/DSM/IRFM, CEA Cadarache (France); Marandet, Y. [PIIM, CNRS-Universite de Provence, Marseille (France)

    2011-07-01

    Full text of publication follows: Research for thermonuclear fusion aims at energy production using fusion reactions between deuterium and tritium nuclei. To this end, a deuterium/tritium mixture has to be heated to a very high temperature (about 100 millions degrees). Chemical and physical sputtering erodes the plasma facing components (PFC), leading to an impurity influx to the plasma. Estimating this erosion source is important both for the PFC lifetime and the quality of the confinement. In fact, impurities reaching the plasma core radiate energy and dilute the fuel. In this contribution, we describe an erosion diagnostic operated on the Tore Supra tokamak, consisting in the combination of visible spectroscopy and filtered imaging over a full TPL (Toroidal Pumped Limiter) sector. Quantitative measurements of spectral lines brightness on four spectrometer chords monitoring the TPL top are used to process the corresponding filtered images, namely to remove background emission or unwanted lines. The particle influx from the TPL's vicinity is obtained from photon fluxes measurements [1], which require absolute calibration in intensity of the system. Filtered images provide the spatial pattern of erosion, from which the total eroded carbon flux is reconstructed. The variation of the particle influx with the input power is studied by analyzing a dedicated experimental campaign. References: [1] Behringer K. et al. Plasma Physics and Controlled Fusion, Vol. 31, No. 14, pp. 2059 to 2099, 1989. (authors)

  1. Water leak localization and recovery in Tore Supra

    International Nuclear Information System (INIS)

    Martinez, A.; Samaille, F.; Chantant, M.; Hatchressian, J.C.

    2007-01-01

    For almost 20 years at Tore Supra, plasma facing components (PFCs) are actively cooled by a pressurized water primary loop. Tore Supra can be considered as ITER relevant on this particular aspect. During plasma operation, it happened, that unexpected localized power deposits damaged a PFC leading to more or less large water leaks in the vacuum vessel. The improvement of the procedure to localize the leaky circuits, the investigation of technical solutions for minimizing the amount of water from steam condensation in the vacuum vessel and the optimisation of the quality of the draining and the drying of Tore Supra cooling loop circuits are the result of the experience gained during several years by the analysis of the water leak from plasma facing components (PFCs) and their consequences. Different new specific systems designed and installed during this year to fulfil these objectives are described in this paper

  2. Tore-Supra: a Tokamak with superconducting toroidal field coils

    International Nuclear Information System (INIS)

    Turck, B.

    1987-07-01

    Tore Supra is a tokamak under construction on the site of Cen Cadarache by the Euratom-CEA Association. The machine technology integrates all problems related to the fabrication and the operation of large superconducting coils and of the associated cryogenic system. Tore Supra will provide a significant experience to prepare the next generation of machines for plasma physics and controlled fusion. Tore Supra is specially designed to implement a large physics program. The superconducting coils make possible the study of plasma confinement in long pulses (more than 60s), the impurities and the stability, and the efficiency of additional heating sources (neutral particle beams and radio frequency heating). The opportunity is taken to recall the particular features and requirements of the superconducting coils of the large future tokamaks in order to point out the problems that have to be faced by any new material (superconducting or not)

  3. Manufacture and mechanical test of a TORE SUPRA model coil

    International Nuclear Information System (INIS)

    Aymar, R.; Claudet, G.; Disdier, F.; Hamelin, J.; Libeyre, P.; Mayaux, G.; Meuris, C.; Parain, J.; Torossian, A.

    1980-09-01

    Inside the qualifying test programme, supporting the Tore Supra Design, a reduced scale model of a Bsub(T) coil was fabricated by a large industrial firm. This model coil is provided with the same features as those retained for the complete magnet. Tests of this model coil have been carried out in such a way that most of stresses which will arise in Tore Supra windings are simulated; simultaneously its cryogenic supply is fully representative of the system retained for the complete machine. Operation of the model coil has been found highly stable; under the conditions of applied field and forces a coil transition could be triggered, by an electrical heater located inside the coil, only when the temperature of the superfluid helium bath was close to Tsub(lambda). Thus, design and manufacturing techniques have been qualified satisfactorily to proceed to the next step: fabrication of the superconducting Bsub(T) coils of Tore Supra

  4. New developments on Tore Supra data acquisition units

    International Nuclear Information System (INIS)

    Leroux, F.; Caulier, G.; Ducobu, L.; Goniche, M.; Antar, G.

    2012-01-01

    The Tore Supra data acquisition system (DAS) was designed in the early eighties and has considerably evolved since then. Three generations of data acquisition units still coexist. As cost and maintenance of different operating systems is expensive, it was decided to explore an alternative solution based on an open source operating system (OS) with a disk-less system for the fourth generation. In 2010, Linux distributions for VME bus and PCI bus systems have been evaluated and compared to Lynx OS TM real time OS. The results obtained allowed to choose a version of Linux for VME and PC platform for DAS on Tore Supra. In 2011, the Tore Supra DAS dedicated software was ported on a Linux disk-less PCI platform. The new generation was successfully tested during real plasma experiments on one diagnostic, called DCEDRE. (authors)

  5. Ion temperature profiles along a hydrogen diagnostic beam in a TORE SUPRA tokamak plasma

    International Nuclear Information System (INIS)

    Romannikov, A.; Petrov, Yu.; Platts, P.; Khess, V.; Khutter, T.; Farzhon, Zh.; Moro, F.

    2002-01-01

    By means of corpuscular diagnostics one studies temperature of ions along a diagnostic hydrogen beam. Paper presents comparison of temperature of plasma (deuterium) basic ions measures by means of the active corpuscular diagnostics with temperature of C + carbon ions along a beam. One studies behavior peculiarities of T i ion temperature profiles for TORE-SUPRA different modes, such as: formation of plane and even hollow T i profiles for ohmic modes, variation of T i profiles under operation of an ergodic diverter, difference of temperature of basic ions measured by means of the active corpuscular diagnostics from C +5 temperature. Paper offers clear explanation of these peculiarities [ru

  6. Heat Loads On Tore Supra ICRF Launchers Plasma Facing Components

    International Nuclear Information System (INIS)

    Bremond, S.; Colas, L.; Chantant, M.; Beaumont, B.; Ekedahl, A.; Goniche, M.; Moreau, P.; Mitteau, R.

    2005-01-01

    Understanding the heat loads on Ion Cyclotron Range of Frequency launchers plasma facing components is a crucial task both for operating present tokamaks and for designing ITER ICRF launchers as these loads may limit the RF power coupling capability. Tore Supra facility is particularly well suited to take this issue. Parametric studies have been performed which enables to get an overall detailed picture of the different heat loads on several areas, pointing to different mechanisms at the origin of the heat power fluxes. Lessons are drawned both with regards to Tore Supra possible operational limits and to ITER ICRF launcher design

  7. Ohmic discharges in Tore Supra - Marfes and detached plasmas

    International Nuclear Information System (INIS)

    Vallet, J.C.

    1990-01-01

    The Tore Supra plasma characteristics are given. The observed discharges are either leaning on the graphite inner first wall or limited by movable pump limiters located outboard and at the bottom of the vacuum chamber. The particular plasma conditions which lead to marfes and detached plasmas in ohmically heated He and D2 discharges limited by the inner wall are investigated. The results show that the ratio of radiated power to ohmic power increase linearly with M.g. As M.g rises, attached plasma, marfe and detached plasma are sequentially observed. Detached plasma with an effective radius as small as. 7 times the limiter radius was observed on Tore Supra

  8. First results of the ECE measurements on Tore Supra

    International Nuclear Information System (INIS)

    Garcin, M.; Javon, C.; Laurent, L.; Masset, R.; Rodriguez, L.; Talvard, M.

    1989-01-01

    Since the beginning of the Tore Supra experiments in april 1988, the ECE diagnostic has been partially operated. The main elements of the diagnostic have been tested and first results have been obtained with a Michelson interferometer and a vertical array of antennae. According to the latter arrangement, the first inverted emissivity profiles are presented

  9. Heat loads on Tore Supra ICRF Launchers Plasma Facing Components

    International Nuclear Information System (INIS)

    Bremond, S.; Colas, L.; Beaumont, B.; Chantant, M.; Goniche, M.; Mitteau, R.

    2005-01-01

    Understanding the heat loads on Ion Cyclotron Range of Frequency (ICRF) launchers plasma-facing components is a crucial task both for operating present tokamaks and for designing ITER ICRF launchers as these loads may limit the RF power coupling capability. Tore Supra facility is particularly well suited to take this issue. Parametric studies have been performed which enables to get an overall detailed picture of the different heat loads on several areas, pointing to different mechanisms at the origin of the heat power fluxes. It is found that the most critical items for Tore-Supra operation are localized heat loads on the Faraday screen top left corner and vertical edges. Warming up close to maximum temperature limit originally set for protection of the plasma-facing components is found of high power pulses, but no erosion was observed after detailed inspection of the launcher in Tore-Supra vessel. Yet, the associated heat loads could be limiting for Tore-Supra operation in the future, and some dedicated work is under progress to improve the understanding of these power fluxes, pointing out the importance of getting a better knowledge of particle flows in the scrape of layer

  10. Simulation of core turbulence measurement in Tore Supra ohmic regimes

    NARCIS (Netherlands)

    Hacquin, S.; Citrin, J.; Arnichand, H.; Sabot, R.; Bourdelle, C.; Garbet, X.; Kramer-Flecken, A.; Tore Supra team,

    2016-01-01

    This paper reports on a simulation of reflectometry measurement in Tore Supra ohmic discharges, for which the experimental observations as well as gyrokinetic non-linear computations predict a modification of turbulence spectrum between the linear (LOC) and the saturated ohmic confinement (SOC)

  11. Runaway electrons dynamics and confinement in TORE-SUPRA

    International Nuclear Information System (INIS)

    Chatelier, M.; Geraud, A.; Joyer, P.; Martin, G.; Rax, J.M.

    1989-01-01

    Ohmic discharges in TORE-SUPRA are sufficiently long (∼ 6 s) for runaway electrons (R.E.) to reach a steady energy state: their energy limit is determined by the balance between parallel electric field acceleration (20 MeV/V.s in TORE-SUPRA) and radiation losses due to the curvature of the trajectories. When R.E. energy is supposed to be only parallel, this provides estimate of order of 70 MeV (value usually called 'synchrotron limit') reached in less than 2 seconds. Experimental observations on TORE-SUPRA of photoneutron emission together with residual induced radioactivity in the first wall components tend to prove that the actual value is much lower than 70 MeV (i.e. 15-35 MeV). Earlier observations in ORMAK, PLT and TFR already showed R.E. energy a slightly less than expected from standard loop voltage acceleration calculations. Explanations given for this lack of energy (as skin-effect lowering the electric field during the ramp-up phase or balance between continuous creation and losses) seems not to hold on TORE-SUPRA and therefore another mechanism must be considered to explain the R.E. energy limitation. 4 refs., 2 figs

  12. Tore supra: towards the 'long time' fusion. Press journey

    International Nuclear Information System (INIS)

    2008-01-01

    After a recall of the interest in the fusion for the development of energy sources, the document presents the fusion from the solar reaction to the nuclear fusion in laboratory. Then it discusses the great challenges of this technology and the Tore Supra installation. The last part is devoted to ITER and DEMO projects. (A.L.B.)

  13. TORE SUPRA 300 W - 1.75 K refrigerator report

    International Nuclear Information System (INIS)

    Gistau, G.M.; Bonneton, M.; Mart, J.W.

    1988-01-01

    The TORE SUPRA refrigerator is now installed and the acceptance tests have been completed. All equipment has performed above design levels. The liquid ring pumps and cold centrifugal compressors have run for more than 1000 hours. Commissioning and acceptance tests, including cooldown, variable heat load, unscheduled shutdown, power outage and automatic restart, and a 400-hour shakedown run, are described and evaluated

  14. Lower hybrid current drive in Tore Supra and JET

    International Nuclear Information System (INIS)

    Moreau, D.; Gormezano, C.

    1991-01-01

    Recent Lower Hybrid Current Drive (LHCD) experiments in TORE SUPRA and JET are reported. Large multijunction launchers have allowed the coupling of 5MW to the plasma for several seconds with a maximum of 3.8 kW/cm 2 . Measurements of the scattering matrices of the antennae show good agreement with theory. The current drive efficiency in TORE SUPRA is about 0.2 x 10 20 Am -2 /W with LH power alone and reaches 0.4 x 10 20 Am -2 /W in JET thanks to a high volume-averaged electron temperature (1.9 keV) and also to a synergy between Lower Hybrid and Fast Magnetosonic Waves. At n e = 1.5 x 10 19 m -3 in TORE SUPRA, sawteeth are suppressed and m = 1MHD oscillations the frequency of which clearly depends on the amount of LH power are observed on soft X-rays, and also on non-thermal ECE. In Jet ICRH produced sawtooth free periods are extended by the application of LHCD and current profile broadening has been clearly observed consistent with off-axis fast electron populations. LH power modulation experiments performed in TORE SUPRA at n e = 4 x 10 19 m -3 show a delayed central electron heating despite the off-axis creation of suprathermal electrons, thus ruling out the possibility of a direct heating through central wave absorption. A possible explanation in terms of anomalous fast electron transport and classical slowing down would yield a diffusion coefficient of the order of 10 m 2 /s for the fast electrons. Finally, successful pellet fuelling of a partially LH driven plasma was obtained in TORE SUPRA, 28 successive pellets allowing the density to rise to n e = 4 x 10 19 m -3 . This could be achieved by switching the LH power off for 90 ms before each pellet injection, i.e. without modifying significantly the current density profile

  15. Tore Supra. Basic design Tokamak system

    International Nuclear Information System (INIS)

    Aymar, R.; Bareyt, B.; Bon Mardion, G.

    1980-10-01

    This document describes the basic design for the main components of the Tokamak system of Tora Supra. As such, it focuses on the engineering problems, and refers to last year report on Tora Supra (EUR-CEA-1021) for objectives and experimental programme of the apparatus on one hand, and for qualifying tests of the main technical solutions on the other hand. Superconducting toroidal field coil system, vacuum vessels and radiation shields, poloidal field system and cryogenic system are described

  16. The plasma facing components of the Tore Supra ICRF antenna

    International Nuclear Information System (INIS)

    Beaumont, B.; Agarici, G.; Gauthier, E.; Kuus, H.; Schlosser, J.

    1994-01-01

    Two generations of Faraday shields for the Tore Supra ICRH antennas interacting with the edge plasma are presented. The last one, using a film of boron carbide as protective material performs well, proving the relevance of this technique for in vessel equipment submitted to low power fluxes. The different lateral protections used on Tore Supra are submitted to high power fluxes. Finite element calculations allow to assess their performances. One type, using Boron Carbide, can be used to measure the local heat flux. The estimation of this flux confirm the specificity of the edge/RF interaction, which is more than one order of magnitude above the exponential decay observed in ohmic plasmas. (author) 11 refs.; 1 fig

  17. Experience from Tore Supra acquisition system and evolutions

    International Nuclear Information System (INIS)

    Guillerminet, B.; Buravand, Y.; Chatelier, E.; Leroux, F.

    2004-01-01

    The Tore Supra tokamak has been upgraded to explore long duration plasma discharges up to 1000s. Since summer 2001, the acquisition system operates in continuous mode apart of the data processing which is still done after the pulse. In the first part, we explore a few solutions to process continuously the data during the pulse, based on parallel processing on a Linux farm and then on a CONDOR system. The second part is devoted to the Web service exposing the Tore Supra operation. In the last part, the VME acquisition system has been redesigned to keep up with the high data rates required by a few diagnostics. The workflow is now distributed among a few computers. At the end, we give the current status of the realisation and the future planning

  18. Transport and turbulence in TORE SUPRA ohmic discharges

    International Nuclear Information System (INIS)

    Garbet, X.; Payan, J.; Laviron, C.; Devynck, P.; Saha, S.K.; Capes, H.; Chen, X.P.; Coulon, J.P.; Gil, C.; Harris, G.; Hutter, T.; Pecquet, A.L.

    1992-01-01

    The mechanisms underlying the energy confinement behaviour in ohmic tokamak discharges are not yet understood. It is well known that the confinement time increases with the average density and saturates above a critical value of the density, but several explanations exist for this saturation. The present study is an analysis of a set of ohmic discharges in Tore Supra with I p =1.6 MA, B=4 T, R=2.35 m and a=0.78 m, where the average density was increased from 0.9 to 4.2 10 19 m -3 . For these plasma parameters, the energy confinement time given by magnetic measurements saturates for e > ≥ 2.5 10 19 m -3 . It is emphasized here that the onset of ionic turbulence is unlikely in Tore Supra. This conclusion relies on a transport analysis and turbulence measurements by CO 2 laser scattering, whose results are presented in this paper

  19. MHD activity triggered by monster sawtooth crashes on Tore Supra

    International Nuclear Information System (INIS)

    Maget, P; Artaud, J-F; Eriksson, L-G; Huysmans, G; Lazaros, A; Moreau, P; Ottaviani, M; Segui, J-L; Zwingmann, W

    2005-01-01

    The crash of monster sawteeth in Tore Supra ion cyclotron resonance heated plasmas is observed to trigger long-lived magneto hydrodynamic (MHD) activity, dominated by a (m = 3, n = 2) magnetic perturbation at the edge. This phenomenon is reminiscent of the triggering of neoclassical tearing modes, although in Tore Supra the MHD activity decays and eventually vanishes. It can be explained by the linear destabilization of the (3, 2) mode as the current sheet developed in the non-linear stage of the internal kink relaxation gets closer to q = 3/2. However, the lifetime of the (3, 2) island is longer than the period of linear instability. We find that the neoclassical drive is essential for explaining the observed lifetime and width of the island, although the overall dynamics is controlled by the relaxation of the current profile on a resistive time scale

  20. First results of correlation electron cyclotron emission on Tore Supra

    OpenAIRE

    Udintsev, V. S.; Goniche, M.; Ségul, J.L.; Giruzzi, G.; Molina, D.; Turco, F.; Huysmans, G. T. A.; Maget, P.; Krämer-Flecken, A.

    2006-01-01

    Measurements of electron temperature fluctuations by means of correlation electron cyclotron emission (ECE) diagnostics aid in understanding the nature of the turbulent transport infusion plasmas. On Tore Supra tokamak, a 32-channel heterodyne ECE radiometer has been upgraded to include two channels for temperature fluctuation measurements. The central frequency of the yttrium iron garnet filter on each channel is remotely monitored by a driver, allowing one to shift the observation volume in...

  1. The Tore Supra HeII cryogenic system

    International Nuclear Information System (INIS)

    Claudet, G.

    1991-01-01

    The tokamak TORE SUPRA built by the association EURATOM-CEA is routinely operated with a toroidal magnet made of Niobium Titanium cooled at 1.8 K by pressurized HeII. The paper will remind the reasons for such a choice and will describe the corresponding technical solutions. After several years of operation, the validity of the HeII cooling solution will be discussed on the basis of the actual and long term behaviour

  2. Lower hybrid wave coupling in TORE SUPRA through multijunction launchers

    International Nuclear Information System (INIS)

    Litaudon, X.; Bibet, P.; Goniche, M.

    1991-01-01

    The TORE SUPRA Lower Hybrid Current Drive experiments (8MW/3.7GHz) use large phased waveguide arrays (4 rows of 32 waveguides for each of the two 'grills') to couple the waves to the plasma. These launchers are based on the 'Multijunction' principle which allows them to be quite compact but needs to be fully assessed for the design of efficient multi-megawatt antennas in NET/ITER. (author) 5 refs., 6 figs

  3. TORE SUPRA fast reciprocating radio frequency probe (abstract)

    International Nuclear Information System (INIS)

    Thomas, C.E. Jr.; Harris, J.H.; Haste, G.R.; Kwon, M.; Goulding, R.H.; Hoffman, D.J.; Saoutic, B.; Becoulet, A.; Fraboulet, D.; Beaumont, B.; Kuus, H.; Ladurelle, L.; Pascal, J.Y.

    1995-01-01

    A fast reciprocating ion cyclotron range of frequencies (ICRF) probe was installed and operated on TORE SUPRA during 1992/1993. The body of the probe was originally used on the ATF experiment at Oak Ridge National Laboratory. The probe was adapted for use on TORE SUPRA, and mounted on one of the two fast reciprocating probe mounts. The probe consists of two orthogonal single-turn wire loops, mounted so that one loop senses toroidal rf magnetic fields and the other senses poloidal rf magnetic fields. The probe began operation in June, 1993. The probe active area is approximately 5 cm long by 2 cm, and the reciprocating mount has a slow stroke (5 cm/s) of 30 cm and a fast stroke (1.5 m/s) of about 10 cm. The probe was operated at distances from the plasma edge ranging from 30 to -5 cm (i.e., inside the last closed flux surface). The probe design, electronics, calibration, data acquisition, and data processing are discussed. First data from the probe are presented as a function of ICRF power, distance from the plasma, loop orientation, and other plasma parameters. Initial data show parametric instabilities do not play an important role for ICRF in the TORE SUPRA edge and scrape-off-layer (SOL) plasmas. Additionally it is observed that the probe signal has little or no dependence on position in the SOL/plasma edge

  4. Steady state operation and control experiments on Tore Supra

    International Nuclear Information System (INIS)

    Saint-Laurent, F.

    2000-01-01

    The main programme of the Tore Supra tokamak is to investigate the route towards long pulse plasma discharges. Tore Supra is thus equipped with a superconducting toroidal magnet, a full set of actively cooled plasma facing components, and a heating and current drive capability based on high power RF systems connected to actively cooled antennas. After pioneering investigations using the LHCD system alone (2 min and zero loop voltage discharges), recent efforts have concentrated on finding scenarios to couple the two RF heating systems in order to perform high power, long duration discharges. To this aim, 6.5 MW, 25 s as well as 4 MW, 60 s discharges have been successfully achieved. At these high power levels, the plasma-wall interaction becomes a critical issue, and recycling fluxes must be controlled to maintain density and to avoid plasma contamination. All these results contributed to the validation of the upgrade of the Tore Supra first wall components (CIEL project) scheduled for 2000. (author)

  5. ORNL compact loop antenna design for TFTR and Tore Supra

    International Nuclear Information System (INIS)

    Taylor, D.J.; Baity, F.W.; Bryan, W.E.; Hoffman, D.J.; McIlwain, R.L.; Ray, J.M.

    1987-01-01

    The goal supplemental ion cyclotron resonance heating (ICRH) of fusion plasma is to deliver power at high efficiencies deep within the plasma. The technology for fast-wave ICRH has reached the point of requiring ''proof-of-performance'' demonstration of specific antenna configurations of specific antenna configurations and their mechanical adequacy for operating in a fusion environment. Oak Ridge National Laboratory (ORNL) has developed the compact loop antenna concept based on a resonant double loop (RDL) configuration for use in both Tokamak Fusion Test Reactor (TFTR) and the Tore Supra ICRH programs. A description and a comparison of the technologies developed in the two designs are presented. The electrical circuit and the mechanical philosophy employed are the same for both antennas, but different operating environments result in substantial differences in the design of specific components. The ORNL TFTR antenna is designed to deliver 4 MW over a 2-s pulse, and the ORNL Tore Supra antenna is designed for 4 MW and essentially steady-state conditions. The TFTR design embodies the first operations compact RDL antenna, and the Tore Supra antenna extends the technology to an operational duty cycle consistent with reactor-relevant applications. 7 refs., 5 figs

  6. 3400 m/s deuterium pellet injector for Tore Supra

    International Nuclear Information System (INIS)

    Perin, J.P.; Geraud, A.

    1995-01-01

    This paper reports on the Tore Supra high velocity pellet injector which was built in Grenoble and after qualification tests installed on Tore Supra Tokomak where it is used for plasma and ablation studies. By using a two stage light gas gun (TSG) and two cells (φ = 3 mm or 4 mm), unsupported pellets pellets (1 to 3.5 10 21 atoms) made directly in the gun by > [1] have been launched into Tore Supra plasma at speeds between 2400m/s and 3400m/s with a reliability of 80%. These higher pellets velocities (> 2500 m/s) [2] are obtained by the optimization of a TSG and the search for the cryogenic conditions of freezing deuterium with good mechanical properties. In particular, the impurities concentration in deuterium during the condensation process has been studied. Several tens pellets have been injected into ohmically and ICR heated plasma and during LH current drive experiments with a good reliability in the range of 3000m/s. These experiments allowed us to extend significantly the ablation data base. Central penetrations can be reached even for high temperatures plasma (3-5 keV) and very peaked density profiles have been obtained in ohmically and ICR heated plasmas A transient improved confinement regime is then observed, which presents some features similar to the PEP regime obtained on JET. (orig.)

  7. Excitation of beta Alfven eigenmodes in Tore-Supra

    International Nuclear Information System (INIS)

    Nguyen, C; Garbet, X; Sabot, R; Goniche, M; Maget, P; Basiuk, V; Decker, J; Elbeze, D; Huysmans, G T A; Macor, A; Segui, J-L; Schneider, M; Eriksson, L-G

    2009-01-01

    Modes oscillating at the acoustic frequency and identified as beta Alfven eigenmodes (BAEs) have been observed in Tore-Supra under ion cyclotron resonant heating. In this paper, the linear excitation threshold of these modes, thought to be driven by suprathermal ions, is calculated and compared with Tore-Supra observations. Similar studies of the linear excitation threshold of energetic particles driven modes were carried out previously for toroidal Alfven eigenmodes or fishbones. In the case of BAEs, the main point is to understand whether the energetic particle drive is able to exceed ion Landau damping, which is expected to be important in the acoustic frequency range. For this, the BAE dispersion relation is computed and simplified in order to derive a tractable excitation criterion suitable for comparison with experiments. The observation of BAEs in Tore-Supra is found to be in agreement with the calculated criterion and confirms the possibility to trigger these modes in the presence of ion Landau damping. Moreover, the conducted analysis clearly puts forward the role of the global tunable parameters which play a role in the BAE excitation (the magnetic field, the density etc), as well as the role of some plasma profiles. In particular, the outcome of a modification of the shear or of the heating localization is found to be non-negligible and it is discussed in the paper.

  8. Lower hybrid current drive in Tore Supra and jet

    International Nuclear Information System (INIS)

    Moreau, D.; Gormezano, C.

    1991-07-01

    Recent Lower Hybrid Current Drive (LHCD) experiments in TORE SUPRA and JET are reported. Large multijunction launchers have allowed the coupling of 5 MW to the plasma for several seconds with a maximum of 3.8 kW/cm 2 . Measurements of the scattering matrices of the antennae show good agreement with theory. The current drive efficiency in TORE SUPRA is about 0.2 x 10 20 Am -2 /W with LH power alone and reaches 0.4 x 10 20 Am -2 /W in JET thanks to a high volume-averaged electron temperature (1.9 keV) and also to a synergy between Lower Hybrid and Fast Magnetosonic Waves. At average n e = 1.5 x 10 19 m -3 in TORE SUPRA, sawteeth are suppressed and m = 1 MHD oscillations the frequency of which clearly depends on the amount of LH power are observed on soft X-rays, and also on non-thermal ECE. In JET ICRH produced sawtooth-free periods are extended by the application of LHCD (2.9 s. with 4 MW ICRH) and current profile broadening has been clearly observed consistent with off-axis fast electron populations. LH power modulation experiments performed in TORE SUPRA at average n e = 4 x 10 19 m -3 show a delayed central electron heating despite the off-axis creation of suprathermal electrons, thus ruling out the possibility of a direct heating through central wave absorption. A possible explanation in terms of anomalous fast electron transport and classical slowing down would yield a diffusion coefficient of the order of 10 m 2 /s for the fast electrons. Other interpretations such as an anomalous heat pinch or a central confinement enhancement cannot be excluded. Finally, successful pellet fuelling of a partially LH driven plasma was obtained in TORE SUPRA, 28 successive pellets allowing the density to rise to average n e = 4 x 10 19 m -3 . This could be achieved by switching the LH power off for 90 ms before each pellet injection, i.e. without modifying significantly the current density profile

  9. Collection and Characterization of Particulate from the Tore Supra Tokamak (Dec. 1999 Vent)

    International Nuclear Information System (INIS)

    Sharpe, John Phillip

    2002-01-01

    Particulate generated during the operation of a fusion device contributes to the radiological source term associated with accident scenarios in the device. Understanding the mechanisms generating the particulate and correctly describing its physical and chemical behavior is essential for safety analyses of future fusion devices. Knowledge of these mechanisms is gained by collecting and characterizing particulate matter from operating fusion facilities. Tokamak dust, the particulate matter generated during the operation of a tokamak fusion device, was collected from Tore Supra in December 1999, during the initial phase of the scheduled shutdown for installation of advanced plasma facing components. Tore Supra, located at CEA Cadarache, France, is presently the third largest operating tokamak with the capability of long-pulse operation. Eighteen super-conducting coils produce the 4.5 T magnetic field inside a vessel 2.4 m in major radius and 1.2 m in minor radius. Limiter and divertor regimes of operation are possible. In the divertor regime, the circular magnetic configuration is ergodized by six outboard resonant divertor modules that are covered with 12 m2 of carbon fiber composite (CFC) tiles. In addition, some field lines are diverted to actively cooled neutralizing plates made of CuCrZr bars covered with B4C. In the limiter regime, the plasma leans on the actively cooled inboard first wall or on a set of inertially cooled pumped limiters. The first wall area of 12 m2 is covered with both polycrystalline graphite tiles (83%) and CFC tiles (17%). The single outboard limiter is constructed of pyrolitic graphite, and the four toroidally symmetric bottom limiters are constructed of CFC. Figure 1.1 displays the relative location of plasma facing components within the plasma chamber of Tore Supra. In this report, we present in Section 2 the methods used to collect and analyze this dust and describe the selection of sampling locations. Section 3 includes a discussion

  10. A step towards controlled fusion reactors: Tore Supra tokamak with superconducting magnets

    International Nuclear Information System (INIS)

    Turck, B.

    1988-01-01

    Tore Supra technology has to solve all the problems related to the development and the installaion of superconducting coils and associated cryogenic devices. Tore Supra will allow to get a significative experience to prepare next machines. Specifications and needs of tokamaks concerning the superconducting coils of future machines are recalled [fr

  11. Eddy current calculations for the tore supra tokamak

    International Nuclear Information System (INIS)

    Blum, J.; Dupas, L.; Leloup, C.; Thooris, B.

    1983-01-01

    This paper deals with the calculation of the eddy currents in the structures of a Tokamak, which can be assimilated to thin conductors, so that the three-dimensional problem can be reduced mathematically to a two-dimensional one, the variables being two orthogonal coordinates of the considered surface. A variational formulation of the problem in terms of the electric vector potential is then given and a finite element method has been used, which enables to treat the complicated geometry of the toroidal field magnet, the mechanical structures and the vacuum vessels of Tore Supra

  12. Full steady state LH scenarios in Tore Supra

    International Nuclear Information System (INIS)

    Kazarian-Vibert, F.; Litaudon, X.; Arslanbekov, R.; Hoang, G.T.; Moreau, D.; Peysson, Y.

    1995-01-01

    Lower Hybrid discharge have been realised in Tore Supra using feed-back control of the primary circuit voltage such that the loop voltage was maintained exactly to zero near the plasma surface. This new scenario allows the plasma current to float and quickly reach an equilibrium value determined by the current drive efficiency and Lower Hybrid power. Recent experimental results show that, with the new constant flux scenario the coupled plasma and primary currents reach a steady state in less than 10 s which is a good agreement with theoretical expectations. A complete analysis of this scenario is presented. (authors). 8 refs., 3 figs

  13. The design of the helium refrigerator for TORE SUPRA

    International Nuclear Information System (INIS)

    Gistau, G.M.; Claudet, G.

    1984-01-01

    The special cryogenic requirements of TORE SUPRA have called for novel solutions. Pumping the 1,75 K (13 mb) helium bath is achieved by the use of a pair of centrifugal pumps operating at very low temperature, backed up by liquid rings pumps at room temperature. Four oil-lubricated screw compressors mounted in series-parallel form the main cycle helium compression set. The Joule-Thomson expansion valve is replaced by a mechanical expansion engine working with a bi-phase exhaust. The control of the refrigeration system is entirely automatic

  14. The Tore Supra Lower Hybrid Test Bed : improvements and applications

    International Nuclear Information System (INIS)

    Delpech, L.; Achard, J.; Beaumont, B.

    2006-01-01

    Within the CIMES project framework in Tore Supra, a klystron TH2103C (3.7 GHz) is under development at THALES ELECTRON DEVICES. It differs from the previous klystrons used in Tore Supra generator mainly in that it has no modulating anode, the RF output power will reach 700 kW CW, by raising the High Voltage value to 76 kV and a beam current up to 23 A. The Tore Supra test bed is a dedicated facility used for high power tests on RF components or on RF transmitters. It has been improved to integrate the TH2103C klystron and a specific 100 kV solide state switch which control the beam current. Since April 2005, the integration of the first tube (without modulating anode) and the 100 kV switch has been completed in the Test Bed and has allowed the modifications and tests of the interfaces and security system for the devices. Improvements were also made on the cooling loop flow to dissipate a power of 1750 kW CW. With these devices, the RF power routinely available in the Lower Hybrid Test Bed is 400 kW CW. With the development of the TH2103C, detailed studies and tests on RF components which will be used up to 750 kW CW on match load or 700 kW on VSWR = 1.4, are necessary to evaluate their performances and thermal behaviour. The test a crucial component, the recombiner, which adds the RF powers coming from the two RF outputs of the TH2103C and inject the resulted power into one WR284 waveguide to a test load or to the plasma, was completed. Two tests have been performed : a thermal study with 400 kW during 1000 s, and RF pulsed tests on short cuts to increase the value of the electric field inside the component. The experiments and calculations (ANSYS and HFSS codes) validate the use of this device with the TH2103C. A module made with two different Beryllium Oxide RF windows, has been under test. The losses on each window are measured by calorimetric measurements and evaluated by computation with HFSS and ANSYS code. The results are compared. In this paper, the

  15. Temperature oscillating regimes in Tore Supra diagnosed by MHD activity

    International Nuclear Information System (INIS)

    Maget, P.; Imbeaux, F.; Giruzzi, G.; Udintsev, V.S.; Huysmans, G.T.A.; Segui, J.-L.; Goniche, M.; Moreau, Ph.; Sabot, R.; Garbet, X.

    2006-01-01

    This paper describes what we can learn on the regimes of spontaneous electron temperature oscillations discovered in Tore Supra from the analysis of MHD activity. Since the first observations of this oscillating behaviour of plasma equilibrium, and its interpretation as a predator-prey system involving lower hybrid waves power deposition and electron confinement, analysis of MHD modes has confirmed the reality of safety factor profile oscillations. This points towards the importance of rational values of the safety factor in the transition to transport barriers in reversed magnetic shear plasmas

  16. Pellet injection and confinement in the tore supra tokamak

    International Nuclear Information System (INIS)

    Maget, P.

    1998-01-01

    Pellet injection in the centre of tokamak plasmas can lead to an improved confinement regime called PEP (Pellet Enhanced Performance). The present work is dedicated to the mechanisms involved in the PEP regimes obtained in the tokamak Tore Supra. A neoclassical approach of transport shows that it is the anomalous transport, due to plasma turbulence, that causes the enhanced confinement. A linear model describing electrostatic instabilities has been developed in order to study the roles of density profile and current profile during the PEP, in the limit of large growth rates. The effect of radial shear in flows is taken into account by removing the ExB shear flow rate from the linear growth rate, as suggested by non-linear numerical simulations of turbulence. A local transport coefficient is estimated from the knowledge of the linear growth rate and the mode width. We find that the peaked density profile in PEP regime lowers the diffusion coefficient, and that the velocity shear amplifies this effect. The evolution of the current profile is also stabilizing, but this parameter is not known with sufficient accuracy, so that its role in Tore Supra PEP experiments remains uncertain. (author)

  17. Calibration procedures of the Tore-Supra infrared endoscopes

    Science.gov (United States)

    Desgranges, C.; Jouve, M.; Balorin, C.; Reichle, R.; Firdaouss, M.; Lipa, M.; Chantant, M.; Gardarein, J. L.; Saille, A.; Loarer, T.

    2018-01-01

    Five endoscopes equipped with infrared cameras working in the medium infrared range (3-5 μm) are installed on the controlled thermonuclear fusion research device Tore-Supra. These endoscopes aim at monitoring the plasma facing components surface temperature to prevent their overheating. Signals delivered by infrared cameras through endoscopes are analysed and used on the one hand through a real time feedback control loop acting on the heating systems of the plasma to decrease plasma facing components surface temperatures when necessary, on the other hand for physics studies such as determination of the incoming heat flux . To ensure these two roles a very accurate knowledge of the absolute surface temperatures is mandatory. Consequently the infrared endoscopes must be calibrated through a very careful procedure. This means determining their transmission coefficients which is a delicate operation. Methods to calibrate infrared endoscopes during the shutdown period of the Tore-Supra machine will be presented. As they do not allow determining the possible transmittances evolution during operation an in-situ method is presented. It permits the validation of the calibration performed in laboratory as well as the monitoring of their evolution during machine operation. This is possible by the use of the endoscope shutter and a dedicated plasma scenario developed to heat it. Possible improvements of this method are briefly evoked.

  18. Plasma rotation study in Tore Supra radio frequency heated plasmas

    International Nuclear Information System (INIS)

    Chouli, Bilal

    2014-01-01

    Toroidal flows are found to improve the performance of the magnetic confinement devices with increase of the plasma stability and confinement. In ITER or future reactors, the torque from NBI should be less important than in present-day tokamaks. Consequently, it is of interest to study other intrinsic mechanisms that can give rise to plasma rotation in order to predict the rotation profile in experiments. Intriguing observations of plasmas rotation have been made in radio frequency (RF) heated plasmas with little or no external momentum injection. Toroidal rotation in both the direction of the plasma current (co-current) and in the opposite direction (counter-current) has been observed depending on the heating schemes and plasma performance. In Tore Supra, most observations in L-mode plasmas have been in the counter-current direction. However, in this thesis, we show that in lower hybrid current drive (LHCD), the core toroidal rotation increment is in co- or counter-current direction depending on the plasma current amplitude. At low plasma current the rotation change is in the co-current direction while at high plasma current, the change is in the counter-current direction. In both low and high plasma current cases, rotation increments are found to increase linearly with the injected LH power. Several mechanisms in competition which can induce co- or counter-current rotation in Tore Supra LHCD plasmas are investigated and typical order of magnitude are discussed in this thesis. (author) [fr

  19. Particle retention during long discharges in Tore Supra and JET

    International Nuclear Information System (INIS)

    Loarer, T.; Tsitrone, E.; Brosset, C.; Bucalossi, J.; Gunn, J.; Joffrin, E.; Monier-Garbet, P.; Pegourie, B.; Thomas, P.; Lomas, P.; Ongena, J.

    2003-01-01

    The particle balances and the associated particle retentions for the long discharge experiments performed in Tore-Supra and for the L and H mode discharges carried out in JET are reported in this paper. From the reported experiments, the same particle retention behaviors are observed in Tore-Supra and JET in spite of the differences between the plasma geometry and the confinement mode (respectively limiter L-mode and divertor H-mode). A particle retention up to 70-80% of Γ(puff) for the larger gas injection has been obtained in JET. The particle retention behavior observed with the gas puff appears to be strongly dominant in the particle retention process. Indeed, no influence has been noticed from the active pumping, the saturation of the recycling area (0.4 D/C), the precedent discharges history (in terms of total 'particles retained' in the vessel) and even from the disruptions (conditioning). Also, the outgassing between discharges becomes negligible in terms of particle recovering when Γ(puff) and/or the discharge duration are increased. Finally, neither the edge localized modes (ELMs type-I or III) nor the disruptions modify the reported behaviour. For ITER, the particle retention is strictly limited and from the presented results it seems that strong gas injection should be avoided. (A.C.)

  20. Pellet injection and confinement in the tore supra tokamak; Injection de glacons et confinement dans le tokamak tore supra

    Energy Technology Data Exchange (ETDEWEB)

    Maget, P

    1998-09-23

    Pellet injection in the centre of tokamak plasmas can lead to an improved confinement regime called PEP (Pellet Enhanced Performance). The present work is dedicated to the mechanisms involved in the PEP regimes obtained in the tokamak Tore Supra. A neoclassical approach of transport shows that it is the anomalous transport, due to plasma turbulence, that causes the enhanced confinement. A linear model describing electrostatic instabilities has been developed in order to study the roles of density profile and current profile during the PEP, in the limit of large growth rates. The effect ofradial shear in flows is taken into account by removing the ExB shear flow rate from the linear growth rate, as suggested by non-linear numerical simulations of turbulence. A local transport coefficient is estimated from the knowledge of the linear growth rate and the mode width. We find that the peaked density profile in PEP regime lowers the diffusion coefficient, and that the velocity shear amplifies this effect. The evolution of the current profile is also stabilizing, but this parameter is not known with sufficient accuracy, so that its role in Tore Supra PEP experiments remains uncertain. (author)

  1. Integration of advanced feedback control techniques on Tore Supra

    International Nuclear Information System (INIS)

    Barana, O.; Basiuk, V.; Bucalossi, J.

    2006-01-01

    Tore Supra tokamak plays an important role in development and optimisation of steady-state scenarios. Its real-time feedback control system is a key instrument to improve plasma performances. For this reason, new feedback control schemes have been recently put into operation and others are being developed. This work deals with the implementation in Tore Supra of these advanced algorithms, reports the technical details and shows the first positive results that have been achieved. For instance, encouraging results have been obtained in the field of profiles control. Controls of the full width at half maximum of the suprathermal electrons local emission profile at very low loop voltage and of the maximum of the thermal Larmor radius, normalised to the characteristic length of the electron temperature gradient, have been attained. While the first quantity can be directly associated to the current profile, the second one characterises the pressure profile. A new feedback control algorithm, employed to maximise a given quantity by means of a '' Search Optimisation '' technique, has been effectively tested too: the hard X-ray width has been maximised with simultaneous use of lower hybrid heating power and wave parallel index as actuators. These and other promising results, whose detailed description will be given in the article, have been obtained thanks to the real-time availability of several diagnostic systems. Using a shared memory network as communication layer, they send their measurements to a central computing unit that, in its turn, dispatches the necessary requirements to the actuators. A key issue is the possibility to integrate these controls in such a way as to cope with different requests at the same time. As an example, simultaneous control of the plasma current by means of the lower hybrid heating power, of the loop voltage by means of the poloidal field system and of the hard X-ray width through the lower hybrid heating phase shift has been successfully

  2. Study of plasma-wall interactions in Tore-supra; Etude des phenomenes d'interaction plasma/paroi dans Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Ruggieri, R

    2000-01-01

    In tokamaks the interaction between wall and plasma generates impurities that affect the thermonuclear fusion. This thesis is divided into 2 parts. The first part describes the physico-chemical processes that are involved in chemical erosion, the second part deals with the study of the wear of Tore-supra's walls due to chemical erosion. Chapter 1 presents the wall-plasma interaction and reviews the different processes between plasma and carbon that occur in Tore-supra. Chapter 2 considers the various crystallographic and electronic structures of the carbon that interferes with Tore-supra plasma, the evolution of these structures during irradiation and their temperature dependence are studied. Chapter 3 presents a crystallo-chemical study of graphite samples that have undergone different surface treatments: ionic bombardment, annealing and air exposure. This experimental study has been performed by using energy-loss spectroscopy. It is shown that air exposure modifies the crystallo-chemical structure of surfaces, so it is necessary to prevent air from contaminating wall samples from Tore-supra. Chapter 4 presents a parametric study of chemical erosion rate of plasma facing components (LPM) of Tore-supra. A relation such as Y{sub cd4}{alpha}{gamma}{sup -0.1} gives a good agreement for chemical erosion rate between measurements and the numerical values of the simulation. (A.C.)

  3. Current density profile inside q=1 on Tore Supra

    International Nuclear Information System (INIS)

    Joffrin, E.; Desgranges, C.; Sabot, R.; Dubois, M.A.

    1995-01-01

    The Tore Supra polarimeter used to measure the poloidal field distribution is described. The current density profiles are computed in two different ways using the interferometric and polarimetric data in conjunction with the magnetic data and the location of the inversion radius determined by the soft X-ray camera. The current density inside the q=1 surface is investigated for normal and monster sawteeth. Its variation are also measured by the polarimeter and compared with that predicted by the current diffusion equation assuming complete reconnection. Finally, the safety factor profile is compared with that obtained with the striation data of the pellet ablation. The results of the evolution of the q profile during sawteeth are in good agreement with those obtained in other devices. (author) 9 refs.; 4 figs

  4. Brazing of the Tore Supra actively cooled Phase III Limiter

    International Nuclear Information System (INIS)

    Nygren, R.E.; Walker, C.A.; Lutz, T.J.; Hosking, F.M.; McGrath, R.T.

    1993-01-01

    The head of the water-cooled Tore Supra Phase 3 Limiter is a bank of 14 round OFHC copper tubes, curved to fit the plasma radius, onto which several hundred pyrolytic graphite (PG) tiles and a lesser number of carbon fiber composite tiles are brazed. The small allowable tolerances for fitting the tiles to the tubes and mating of compound curvatures made the brazing and fabrication extremely challenging. The paper describes the fabrication process with emphasis on the procedure for brazing. In the fixturing for vacuum furnace brazing, the tiles were each independently clamped to the tube with an elaborate set of window frame clamps. Braze quality was evaluated with transient heating tests. Some rebrazing was necessary

  5. Current diffusion and flux consumption in Tore Supra

    International Nuclear Information System (INIS)

    Van Houtte, D.; Talvard, M.; Agostini, E.; Gil, C.; Hoang, G.T.; Lecoustey, P.; Parlange, F.; Rodriguez, L.; Vallet, J.C.

    1991-01-01

    TORE SUPRA has been designed to study long pulse plasmas (t > 30 s) at high plasma current (Ip < 2 MA) associated with high additional power (20 MW). Current diffusion studies are essentially based on the analysis of the plasma discharge paths. The current diffusion rate during the current rise phase is analysed with a numerical code using plasma resistivity profiles from Te profiles measured by the ECE diagnostic. Owing to the fact that the quantity of magnetic flux available in a tokamak is limited, perfect knowledge is required of the various components of the flux consumed in order to minimize consumption and to be able to define a suitable transformer size for future high current tokamak projects

  6. Temperature gradient driven electron transport in NSTX and Tore Supra

    International Nuclear Information System (INIS)

    Horton, W.; Wong, H.V.; Morrison, P.J.; Wurm, A.; Kim, J.H.; Perez, J.C.; Pratt, J.; Hoang, G.T.; LeBlanc, B.P.; Ball, R.

    2005-01-01

    Electron thermal fluxes are derived from the power balance for Tore Supra (TS) and NSTX discharges with centrally deposited fast wave electron heating. Measurements of the electron temperature and density profiles, combined with ray tracing computations of the power absorption profiles, allow detailed interpretation of the thermal flux versus temperature gradient. Evidence supporting the occurrence of electron temperature gradient turbulent transport in the two confinement devices is found. With control of the magnetic rotational transform profile and the heating power, internal transport barriers are created in TS and NSTX discharges. These partial transport barriers are argued to be a universal feature of transport equations in the presence of invariant tori that are intrinsic to non-monotonic rotational transforms in dynamical systems

  7. An advanced plasma control system for Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Wijnands, T.; Martin, G.

    1996-01-01

    First results on plasma control with the new plasma control system of Tore Supra are presented. The system has been especially designed for long pulse operation: plasmas are controlled on reference signals, which can be varied in real time by using diagnostic measurements. On line determination of the global plasma equilibrium has enabled new operation scenarios in which both the power from the poloidal field generators and the total Lower Hybrid (LH) power are used to control the plasma. Experiments with feedback control of the safety factor on the plasma boundary, control of the LH driven current, control of the flux on the plasma boundary and control of the internal inductance are discussed. (author). 12 refs.

  8. Edge plasma density convection during ICRH on Tore Supra

    International Nuclear Information System (INIS)

    Becoulet, M.; Colas, L.; Gunn, J.; Ghendrih, Ph.; Becoulet, A.; Pecoul, S.; Heuraux, S.

    2001-11-01

    The 2D edge plasma density distribution around ion cyclotron resonance heating (ICRH) antennae is studied experimentally and numerically in the tokamak Tore Supra (TS). A local density decrease in front of the loaded ICRH antenna ('pump-out' effect) is demonstrated by Langmuir probe measurements in a low recycling regime. An up-down asymmetry in the heat-flux and in the antenna erosion is also observed, and is associated with poloidal variations of the local density. These density redistributions are ascribed to an ExB convection process linked with RF-sheaths. To assess this interpretation, the 2D transport code CELLS was developed for modeling the density distribution near an antenna. The code takes into account perpendicular diffusion, parallel transport and convection in RF-sheath-driven potentials given by the 3D-antenna code ICANT. The strong density differences obtained in simulations reproduce up-down asymmetries of the heat fluxes. (authors)

  9. Eddy current calculations for the Tore Supra toroidal field magnet

    International Nuclear Information System (INIS)

    Blum, J.

    1983-01-01

    An outline is given of the calculation of the eddy currents in the magnetic structures of a Tokamak, which can be assimilated to thin conductors, so that the three-dimensional problem can be reduced mathematically to a two-dimensional one, the variables being two orthogonal coordinates of the considered surface. A finite element method has been used in order to treat the complicated geometry of the set of the 18 toroidal field coil casings and mechanical structures of Tore Supra. This eddy current code has been coupled with an axisymmetric equilibrium code in order to simulate typical phases of a Tokamak discharge (plasma current rise, additional heating, disruption, cleaning discharge) and the losses in the toroidal field magnet have thus been calculated. (author)

  10. Replacement of the instrumentation and control system of Tore Supra

    International Nuclear Information System (INIS)

    Leveque, P.

    1995-02-01

    The control system of the Tore-Supra is a wide and complex system that cannot be interrupted while running without significant consequences on the operating of the machine. Replacing the current system cannot be achieved in a global way without immobilisation and high costs. Therefore partial changes have been decided on. This work presents the detailed analysis of the arrangements and the operating of the system that will be replaced: the pro's and con's that have appeared through experience are related. The possibilities that the new apparatus offers are also examined. A method of step by step replacements had to be set up in order to assess the means, funds, term of achievement, performance and quality of the overall project. (TEC). 15 refs., 29 figs

  11. Overview of recent results from the Tore Supra ECE diagnostics

    International Nuclear Information System (INIS)

    Talvard, M.; Liu, W.D.; Giruzzi, G.

    1993-01-01

    The Tore Supra ECE diagnostic system consists of a set of 3 Michelson and 12 Fabry-Perot interferometers, which is now fully operational. We present results obtained with the 3 Michelson during LHCD experiments first. It is shown how the sensitivity of the diagnostic to rather high v (perpendicular) prevents detection of v (parallel) anisotropies. On the other hand, measurements during the Ohmic phase reveal some unexpected anisotropy which can be attributed to superthermal electrons related to the bootstrap current. The 12 Fabry-Perot have been operated using high acquisition sampling rates during pellet injection experiments. A shudder preceding the pellet itself is clearly evidenced just before an internal disruption occurs. During sawtooth activity, such measurements are also used to study the dynamics of the m=1, n=1 instability on the q=1 surface itself

  12. ITER-like PAM launcher for tore supra's LHCD system

    International Nuclear Information System (INIS)

    Belo, J.H.; Bibet, Ph.; Missirlian, M.; Achard, J.; Beaumont, B.; Bertrand, B.; Chantant, M.; Chappuis, Ph.; Doceul, L.; Durocher, A.; Gargiulo, L.; Saille, A.; Samaille, F.; Villedieu, E.

    2004-01-01

    A new launcher based upon the PAM concept (Passive-Active Multijunction) already proposed for ITER has been developed and is currently under realisation at Tore Supra. It was designed for an injection power capability of 2.7 MW CW at 3.7 GHz, a power density of 25 MW/m 2 , to radiate a power spectrum peaked at N || = 1.7 with a maximum power directivity near the electron cut-off density and with very good coupling properties on a wide range of electron densities. In this paper an overall description of the antenna as well as the foreseen manufacturing and assembling processes are given, followed by the results from studies and optimizations of its RF components, and by a stress analysis of its thermomechanical behaviour. (authors)

  13. New fast switches for the Tore Supra ohmic heating circuit

    International Nuclear Information System (INIS)

    Zunino, K.; Bruneth, J.; Cara, P.; Louart, A.; Santagiustina, A.; Emelyanova, I.; Filippov, F.; Mikailov, N.

    2003-01-01

    The Tore-Supra ohmic heating circuit is equipped with four fast make switches and one fast opening switch. After many years of operation, it became necessary to substitute this equipment by modern components with similar ratings. An extensive research has been undertaken to find fast switches able to withstand more than 2500 operations per year without maintenance, at a make current of 54 kA, a voltage of 12 kV and with a closing time of less than 15 ms. At the end of the investigation, it was decided to replace the old components by fast mechanical switches proposed by the Efremov Institute and based on a prototype developed for ITER. This paper presents the technical requirements and the characteristics of the switches and describes the operational experience gained with these components during operating campaigns of 2002 and 2003. (authors)

  14. Scrape-off layer flows in the Tore Supra tokamak

    International Nuclear Information System (INIS)

    Gunn, J.P.; Loarer, T.; Saint-Laurent, F.; Bucalossi, J.; Devynck, P.; Hertout, P.; Moreau, P.; Nanobashvili, I.; Rimini, F.; Duran, I.; Fuchs, V.; Panek, R.; Stockel, J.; Adamek, J.; Dejarnac, R.; Hron, M.; Sarkissian, A.

    2005-01-01

    Near-sonic parallel flows are systematically observed in the scrape-off layer (SOL) of the limiter tokamak Tore Supra, as in many X-point divertor tokamaks. The poloidal variation of the Mach number of the parallel flow has been measured by moving the contact point of a small circular plasma onto limiters at different poloidal angles. The resulting variations of flow are consistent with the existence of a poloidally nonuniform core-to-SOL out-flux concentrated near the outboard midplane. Strong variations of the SOL width up to a factor of 10 suggest that this localized out-flux is due to enhanced radial transport. The plasma that gets ejected into the SOL can expand radially to the wall if magnetic field lines have long connection lengths and pass unobstructed across the outboard midplane. (authors)

  15. Pneumatic injector of deuterium macroparticles for TORE-SUPRA tokamak

    International Nuclear Information System (INIS)

    Vinyar, I.V.; Umov, A.P.; Lukin, A.Ya.; Skoblikov, S.V.; Reznichenko, P.V.; Krasil'nikov, I.A.

    2006-01-01

    The pneumatic injector for periodic injection of fuel-solid-deuterium pellets into the plasma of the TORE-SUPRA tokamak in a steady-state mode is described. The deuterium pellet injection with an unlimited duration is ensured by a screw extruder in which gaseous deuterium is frozen and squeezed outwards in the form of a rod with a rectangular cross section. A cutter installed on the injector's barrel cuts a cylinder with a diameter of 2 mm and a length of 1.0-3.5 mm out from this rod. The movement of the cutter is controlled by a pulsed electromagnetic drive at a pulse repetition rate of 10 Hz. In the injector's barrel, a compressed gas accelerates a deuterium pellet to a velocity of 100-650 m/s [ru

  16. Edge plasma density convection during ICRH on Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Becoulet, M.; Colas, L.; Gunn, J.; Ghendrih, Ph.; Becoulet, A. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Pecoul, S.; Heuraux, S. [Nancy-1 Univ., 54 (France). Lab. de Physique des Milieux Ionises

    2001-11-01

    The 2D edge plasma density distribution around ion cyclotron resonance heating (ICRH) antennae is studied experimentally and numerically in the tokamak Tore Supra (TS). A local density decrease in front of the loaded ICRH antenna ('pump-out' effect) is demonstrated by Langmuir probe measurements in a low recycling regime. An up-down asymmetry in the heat-flux and in the antenna erosion is also observed, and is associated with poloidal variations of the local density. These density redistributions are ascribed to an ExB convection process linked with RF-sheaths. To assess this interpretation, the 2D transport code CELLS was developed for modeling the density distribution near an antenna. The code takes into account perpendicular diffusion, parallel transport and convection in RF-sheath-driven potentials given by the 3D-antenna code ICANT. The strong density differences obtained in simulations reproduce up-down asymmetries of the heat fluxes. (authors)

  17. An advanced plasma control system for Tore Supra

    International Nuclear Information System (INIS)

    Wijnands, T.; Martin, G.

    1996-01-01

    First results on plasma control with the new plasma control system of Tore Supra are presented. The system has been especially designed for long pulse operation: plasmas are controlled on reference signals, which can be varied in real time by using diagnostic measurements. On line determination of the global plasma equilibrium has enabled new operation scenarios in which both the power from the poloidal field generators and the total Lower Hybrid (LH) power are used to control the plasma. Experiments with feedback control of the safety factor on the plasma boundary, control of the LH driven current, control of the flux on the plasma boundary and control of the internal inductance are discussed. (author)

  18. Statistical study of density fluctuations in the tore supra tokamak

    International Nuclear Information System (INIS)

    Devynck, P.; Fenzi, C.; Garbet, X.; Laviron, C.

    1998-03-01

    It is believed that the radial anomalous transport in tokamaks is caused by plasma turbulence. Using infra-red laser scattering technique on the Tore Supra tokamak, statistical properties of the density fluctuations are studied as a function of the scales in ohmic as well as additional heating regimes using the lower hybrid or the ion cyclotron frequencies. The probability distributions are compared to a Gaussian in order to estimate the role of intermittency which is found to be negligible. The temporal behaviour of the three-dimensional spectrum is thoroughly discussed; its multifractal character is reflected in the singularity spectrum. The autocorrelation coefficient as well as their long-time incoherence and statistical independence. We also put forward the existence of fluctuations transfer between two distinct but close wavenumbers. A rather clearer image is thus obtained about the way energy is transferred through the turbulent scales. (author)

  19. Study of heat flux deposition in the Tore Supra Tokamak

    International Nuclear Information System (INIS)

    Carpentier, S.

    2009-02-01

    Accurate measurements of heat loads on internal tokamak components is essential for protection of the device during steady state operation. The optimisation of experimental scenarios also requires an in depth understanding of the physical mechanisms governing the heat flux deposition on the walls. The objective of this study is a detailed characterisation of the heat flux to plasma facing components (PFC) of the Tore Supra tokamak. The power deposited onto Tore Supra PFCs is calculated using an inverse method, which is applied to both the temperature maps measured by infrared thermography and to the enthalpy signals from calorimetry. The derived experimental heat flux maps calculated on the toroidal pumped limiter (TPL) are then compared with theoretical heat flux density distributions from a standard SOL-model. They are two experimental observations that are not consistent with the model: significant heat flux outside the theoretical wetted area, and heat load peaking close to the tangency point between the TPL and the last closed field surface (LCFS). An experimental analysis for several discharges with variable security factors q is made. In the area consistent with the theoretical predictions, this parametric study shows a clear dependence between the heat flux length λ q (estimated in the SOL (scrape-off layer) from the IR measurements) and the magnetic configuration. We observe that the spreading of heat fluxes on the component is compensated by a reduction of the power decay length λ q in the SOL when q decreases. On the other hand, in the area where the derived experimental heat loads are not consistent with the theoretical predictions, we observe that the spreading of heat fluxes outside the theoretical boundary increases when q decreases, and is thus not counterbalanced. (author)

  20. Parametric dependences of impurity transport in the Tore Supra tokamak

    International Nuclear Information System (INIS)

    Parisot, Th.

    2007-09-01

    During this Ph.D. work, a full setup of tools for an experimental investigation of impurity transport has been developed on the Tore Supra tokamak. It includes a laser blow-off system for metallic impurity injections and developments for ITC (Impurity Transport Code), a transport code which allows the extraction of the experimental impurity transport coefficients (diffusion and convection velocity). This tool has been used to perform and analyse several experiments, to evidence parametric dependences of impurity transport. In a first experiment, a confinement time law for nickel in Tore Supra has been obtained as a function of collisionality ν * and normalized Larmor radius ρ * . Then the impurity charge Z role has been investigated in various conditions: ohmic regime with or without sawteeth, and sawtooth less L-mode with LH power. No Z effect is observed, consistently with theoretical predictions, whether neoclassical (NCLASS) or for turbulent transport with both non linear gyro-fluid (TRB) and quasilinear gyrokinetic (QuaLiKiz) simulations. An exception is found for LH heated plasmas where the confinement time seems to decrease for the heaviest impurities. This is not explained by any model available. The observed transport is close to neoclassical between sawtooth relaxations, in the centre (r q-1 ) of ohmic plasmas, turbulent outside. Without sawteeth, it is turbulent in the whole plasma, for ohmic or L mode discharges. The profile shape of the diffusion coefficient is here qualitatively different, with a stronger and deeper transition between the low diffusion central region and a more turbulent peripheral region for LH heated plasmas. (author)

  1. Calibration of Fabry-Perot interferometers for electron cyclotron emission measurements on the Tore Supra tokamak

    International Nuclear Information System (INIS)

    Javon, C.; Talvard, M.

    1990-01-01

    The electron temperature is routinely measured on TORE SUPRA using Fabry-Perot cavities. These have been calibrated using a technique involving coherent addition and Fourier analysis of a chopped black-body source. Comparison with conventional techniques is reported

  2. 300 W - 1.75 K TORE SUPRA refrigerator cold centrifugal compressors report

    International Nuclear Information System (INIS)

    Gistau, G.M.; Pecoud, Y.; Ravex, A.E.

    1988-01-01

    The centrifugal helium compressors for the TORE SUPRA tokamak refrigerator were designed and manufactured by L'Air Liquide and tested at nominal conditions on a custom test rig. The refrigerator is now installed and all acceptance tests have been completed. Other tests were carried out off design conditions with the machines installed in the TORE SUPRA refrigerator. The results of these tests, including compression ratio, efficiency, and heat losses, are discussed

  3. Replacement of the instrumentation and control system of Tore Supra; Remplacement du systeme de controle commande de Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Leveque, P

    1995-02-01

    The control system of the Tore-Supra is a wide and complex system that cannot be interrupted while running without significant consequences on the operating of the machine. Replacing the current system cannot be achieved in a global way without immobilisation and high costs. Therefore partial changes have been decided on. This work presents the detailed analysis of the arrangements and the operating of the system that will be replaced: the pro`s and con`s that have appeared through experience are related. The possibilities that the new apparatus offers are also examined. A method of step by step replacements had to be set up in order to assess the means, funds, term of achievement, performance and quality of the overall project. (TEC). 15 refs., 29 figs.

  4. Study of heat flux deposition in the Tore Supra Tokamak; Etude des depots de chaleur dans le tokamak Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Carpentier, S.

    2009-02-15

    Accurate measurements of heat loads on internal tokamak components is essential for protection of the device during steady state operation. The optimisation of experimental scenarios also requires an in depth understanding of the physical mechanisms governing the heat flux deposition on the walls. The objective of this study is a detailed characterisation of the heat flux to plasma facing components (PFC) of the Tore Supra tokamak. The power deposited onto Tore Supra PFCs is calculated using an inverse method, which is applied to both the temperature maps measured by infrared thermography and to the enthalpy signals from calorimetry. The derived experimental heat flux maps calculated on the toroidal pumped limiter (TPL) are then compared with theoretical heat flux density distributions from a standard SOL-model. They are two experimental observations that are not consistent with the model: significant heat flux outside the theoretical wetted area, and heat load peaking close to the tangency point between the TPL and the last closed field surface (LCFS). An experimental analysis for several discharges with variable security factors q is made. In the area consistent with the theoretical predictions, this parametric study shows a clear dependence between the heat flux length lambda{sub q} (estimated in the SOL (scrape-off layer) from the IR measurements) and the magnetic configuration. We observe that the spreading of heat fluxes on the component is compensated by a reduction of the power decay length lambda{sub q} in the SOL when q decreases. On the other hand, in the area where the derived experimental heat loads are not consistent with the theoretical predictions, we observe that the spreading of heat fluxes outside the theoretical boundary increases when q decreases, and is thus not counterbalanced. (author)

  5. Water Leak Localisation and Recovery in Tore Supra

    International Nuclear Information System (INIS)

    Martinez, A.; Samaille, F.; Chantant, M.; Hatchressian, J.-C.

    2006-01-01

    For almost 20 years, Tore Supra (TS) Tokamak uses water as a coolant for its plasma facing and in-vessels components. It can be considered as ITER relevant on this particular aspect. During plasma operation in TS, the water inlet temperature and outlet pressure are 120 o C and 2.4 MPa respectively, while baking is performed at 200 o C and 2 Mpa. It happened, that unexpected localized power deposits damaged in-vessels components leading to more or less large water leaks. In order to protect the vacuum vessel from over-pressurisation in case of large water leaks and to avoid the release of eventual activated materials, a pressure suppression system, composed of two rupture disks and a relief pipe header, has been designed. In the event of smaller leaks, the issue for Tore Supra operations is to apply methods capable of detecting and localising leaking water cooling circuits inside the vacuum vessel within an acceptable time. For this purpose, drainage and drying systems have been designed and manufactured to evacuate completely the water in the components and vacuum vessel, facilitating, in that way, leak testing procedure of the components. A new system allows the localization of the leaky circuit remotely by using the cooling loops monitoring system. The sub-circuits can be selected, isolated and de pressurized by the operator. Simultaneously the vacuum is monitored in the vessel and analyzed with a mass spectrometer. The water resulting from the steam condensation in the cold parts of the vacuum vessel is pumped by a new specific vacuum system in the lower parts of the machine and stored in tanks to avoid dissipation of activated products in the environment. Filters are implemented on the outlets lines of the pumps. The in-vessels components fed by the upper part of the cooling loop are connected in parallel and the water inlets and outlets are located on top of the machine, so some difficulties were encountered to drain-off completely this components. Presently

  6. Java graphical user interface for the supervision of Tore Supra

    International Nuclear Information System (INIS)

    Utzel, Nadine; Guillerminet, Bernard; Leluyer, Mireille; Moulin, Daniele

    2002-01-01

    The graphical user interface (GUI) for the supervision of Tore Supra is intended to supervise the start-up and the shut-down of the installation, to control general state (state of all diagnostics, state of the system and network) and to follow the pulse sequence. Implementation of a new multi-platform, modular GUI for Tore Supra is in progress. This provides not only a simpler, more structured view for the non-specialist user, but also is open-ended and adaptable to a wide variety of uses. The actual implementation of a GUI is a question of user-ergonomics. Hence, a user-directed study in 2000 produced a specification for the interface. The information is treated with a hierarchical order. At the top level, only the global state of the supervised elements appears, i.e. the general state of every diagnostics, the pulse sequence, the safety systems. If a problem occurs, the operator has access to the lower level detailed state of the concerned element, simply with a double-click. An event log also helps the operator to analyse the chronology of the alarms arising during the pulse. Although the GUI is mainly used in the control room on X terminals under Unix, it should also be accessible via a portable PC for the purpose of maintenance, or directly from any office to see how the physics program is progressing. The choice of Java, multi-platform object programming language was thus adopted with access via any web browser. The modularity of the GUI is made possible by a distributed architecture (remote method invocation) between the graphic client and different servers: one for the diagnostics and the sequence, one for the system and the network and one for the configuration database. All the components interact with each other in a very simple and standard way. This distributed architecture allows the progressive set up of the new interface. The first step, being produced for mid-2001 is the GUI for the supervision of diagnostics. This prototype will help us to

  7. Java graphical user interface for the supervision of Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Utzel, Nadine E-mail: nutzel@cea.fr; Guillerminet, Bernard; Leluyer, Mireille; Moulin, Daniele

    2002-06-01

    The graphical user interface (GUI) for the supervision of Tore Supra is intended to supervise the start-up and the shut-down of the installation, to control general state (state of all diagnostics, state of the system and network) and to follow the pulse sequence. Implementation of a new multi-platform, modular GUI for Tore Supra is in progress. This provides not only a simpler, more structured view for the non-specialist user, but also is open-ended and adaptable to a wide variety of uses. The actual implementation of a GUI is a question of user-ergonomics. Hence, a user-directed study in 2000 produced a specification for the interface. The information is treated with a hierarchical order. At the top level, only the global state of the supervised elements appears, i.e. the general state of every diagnostics, the pulse sequence, the safety systems. If a problem occurs, the operator has access to the lower level detailed state of the concerned element, simply with a double-click. An event log also helps the operator to analyse the chronology of the alarms arising during the pulse. Although the GUI is mainly used in the control room on X terminals under Unix, it should also be accessible via a portable PC for the purpose of maintenance, or directly from any office to see how the physics program is progressing. The choice of Java, multi-platform object programming language was thus adopted with access via any web browser. The modularity of the GUI is made possible by a distributed architecture (remote method invocation) between the graphic client and different servers: one for the diagnostics and the sequence, one for the system and the network and one for the configuration database. All the components interact with each other in a very simple and standard way. This distributed architecture allows the progressive set up of the new interface. The first step, being produced for mid-2001 is the GUI for the supervision of diagnostics. This prototype will help us to

  8. Tore supra: towards the 'long time' fusion. Press journey; Tore Supra: vers la fusion 'longue duree'. Voyage de presse

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    After a recall of the interest in the fusion for the development of energy sources, the document presents the fusion from the solar reaction to the nuclear fusion in laboratory. Then it discusses the great challenges of this technology and the Tore Supra installation. The last part is devoted to ITER and DEMO projects. (A.L.B.)

  9. Improvement of density control by feedback on Langmuir probe signals in Tore Supra

    International Nuclear Information System (INIS)

    Gunn, J.; Bucalossi, J.; Costanzo, L.; Grisolia, C.; Ghendrih, Ph.; Grosman, A.; Loarer, T.; Martin, G.; Monier-Garbet, P.; Moulin, D.; Pascal, J.Y.; Saint-Laurent, F.

    1999-12-01

    Real time control of deuterium or helium gas injection by feedback on Langmuir probe signals is implemented in Tore Supra ergodic divertor discharges. The feedback schemes are based on the robust experimental observation that the density limit coincides with edge temperature T e ∼ 10 eV. Three control algorithms are used: (1) proportional feedback on the central line-averaged density with real-time attenuation of the system gain and security cut-off of the gas injection if the edge temperature becomes too low; (2) proportional feedback on the central line-averaged density with security cut-off controlled by the degree of detachment (DoD); (3) proportional feedback on edge temperature with security cut-off on the DoD. The DoD is defined for deuterium discharges, but not for helium since those do not detach. All three feedback modes permit operation close to the density limit and have been successfully applied for plasma currents 0.4 p p =1.4 MA with up to 4 MW of ICRH power. (author)

  10. Probing neutral density at the plasma edge of Tore Supra with CX excited impurity ions

    International Nuclear Information System (INIS)

    Hess, W.R.; Mattioli, M.; Guirlet, R.

    1993-01-01

    In Tokamak plasma physics renewed interest in visible spectroscopy has grown for two reasons. The use of fiber optics allows observation of local sources of both impurities and of hydrogen by observing radiation of low ionization states. Moreover, charge exchange spectroscopy (CXS) with either auxiliary or heating neutral beams is a standard technique to determine the ion temperature and impurity density profiles. After a short description of the experimental setup and the ergodic divertor of Tore Supra (TS), two discharges in which space-resolved observations of the CVI (8-7) line clearly show the presence of CX-related effects. A well isolated spectral line at 5304.6 A is discussed. Tentative identification as CIII (1s 2 2s, 7-5) is suggested. The conclusion shows the usefulness of the reported results for probing neutral density at the plasma edge by detecting CX excited impurity ions and that highly ionized C 6+ ions exist in the MARFE regions. To the best of our knowledge, only very low ionization C and O ions (such as CIII or OIV) have been previously reported in these regions

  11. Design of new antenna for LHCD on Tore Supra

    International Nuclear Information System (INIS)

    Bibet, Ph.; Berger-By, B.; Goniche, M.; Rey, G.; Tonon, G.; Nguyen, T.K.

    1994-01-01

    For the purpose of driving the Tore Supra, the estimation of the system was performed, and a mode converter has been developed, and the poloidal junction between the oversized waveguide at the output of the mode converter and three ports has been studied. The module is composed of a raised cosine taper connected to the mode converter, a poloidal junction with one main oversized waveguide and three output waveguides, an E plane linear taper and E plane multi-junctions. For computing the taper and the mode converter, the telegraphist equation which is derived from Maxwell equations was solved by Unger method. To avoid numerical divergence, the different components were divided into many parts depending on the number of propagating modes. The poloidal junction and the multi-junctions have been studied by considering two specific modes. These were for considering the theoretical models for defining the taper and the mode converter and for the poloidal junction and the multi-junctions. The numerical results of the raised cosine taper, the mode converter, the poloidal junction and the multi-junctions are reported. After the experimental checkup on the low level mock-up, a module will be realized for the high power test. (K.I.)

  12. Snake-like phenomena in Tore Supra following pellet injection

    International Nuclear Information System (INIS)

    Pecquet, A.L.; Cristofani, P.; Mattioli, M.; Garbet, X.; Laurent, L.; Geraud, A.; Gil, C.; Joffrin, E.; Sabot, R.

    1996-01-01

    Snakes are observed in Tore-Supra, after injection of high velocity solid hydrogen or deuterium pellets ablated inside the q=1 surface. They are detected, immediately after the ablation, as oscillations on the line integrated densities of the central interferometer channels. The corresponding oscillations on the soft X-ray signals detach from the noise about 70 ms later. Snakes survive sawtooth crashes, but are nevertheless affected by them. Variations, during the about 500 ms long lifetime, of the snake radius τ s , of the rotation frequency and of the rotation direction are discussed, stressing the effects of the sawtooth crashes. In many snakes τ s /τ q =1 is of the order of 0.5. Since the snake has a m=1, n=1 helicity, this points out the existence of a flat or inverted safety factor profile, confirmed by calculation of the current profile using Spitzer's resistivity. Combined simulations of the snake oscillations on both interferometer and soft X-ray signals have indicated that, starting about 80 ms after the snake formation, the impurity (carbon) density inside the snake is much larger than outside it. Since a change of regime seems to appear about 80 ms after the snake formation on the soft X-ray, it seems plausible that impurity (carbon) accumulation takes place at this time. A stability criterion taking into account both impurity and bootstrap effects is presented, the result agrees with the model proposed by Wesson. (authors)

  13. Turbulence and energy confinement in TORE SUPRA ohmic discharges

    International Nuclear Information System (INIS)

    Garbet, X.; Payan, J.; Laviron, C.; Devynck, P.; Saha, S.K.; Capes, H.; Chen, X.P.; Coulon, J.P.; Gil, C.; Harris, G.; Hutter, T.; Pecquet, A.L.

    1992-06-01

    Results on confinement and turbulence from a set of ohmic discharges in Tore Supra are discussed. The attention is focused on the saturation of the energy confinement time and it is emphasized that this saturation could be explained by a saturation of the electron heat diffusivity. Ion behaviour is indeed governed by dilution and equipartition effects. Although the ion heat transport is never neoclassical, there is no enhanced degradation at the saturation. This behaviour is confirmed by turbulence measurements given by CO 2 laser coherent scattering. The density fluctuations level follows the electron heat diffusivity variations with the average density. Waves propagating in the ion diamagnetic direction are always present in turbulence frequency spectra. Thus, the saturation cannot be explained by the onset of an ion turbulence. The existence of an ion turbulence at the edge at all densities cannot be excluded. However, this ion feature in scattering spectra could be explained by a Doppler shift associated to an inversion point of the radial electric field at the edge

  14. Long discharge particle balance and fuel retention in Tore Supra

    International Nuclear Information System (INIS)

    Pegourie, B.; Brosset, C.; Delchambre, E.; Loarer, T.; Tsitrone, E.; Bucalossi, J.; Gunn, J.; Reichle, R.; Khodja, H.; Lafon, C.; Parent, P.

    2003-01-01

    In the new CIEL configuration of Tore-Supra, all the plasma facing components are actively cooled. The surface of the wall covered with carbon is about 15 m 2 (2-4 m 2 of which in close interaction with the plasma). This configuration allowed to maintain steady-state plasma conditions during up to 4 min 25 s. In these experiments, the required gas injection for maintaining the prescribed density remains constant during the whole discharge. The exhausted flux is also constant and equal to 40-50% of the injected flux. Therefore, 50-60% of the injected particles remain trapped in the vessel, the total retention being proportional to the plasma duration. Since the gas recovered between shots or by conditioning techniques is far from balancing the injected gas, huge quantities of deuterium remain indefinitely trapped in the wall, which appears as an infinite reservoir. This reservoir is believed to be dominated by co-deposited layers, as observed in several places of the vessel. The thickest deposits (up to 800 μm) are observed on the leading edge of the neutralizers of the exhaust system. They display a column-like shape (typical growth rate ∼ 20 nm/s) and have a graphite-like structure. Their deuterium content is modest. Conversely, when coming from regions protected from the direct plasma flux, the deposits show a smoother shape and their deuterium content is typically an order of magnitude larger. (authors)

  15. Multichannel and multicolor infrared thermography in Tore Supra

    International Nuclear Information System (INIS)

    Reichle, R.; Pocheau, C.; Balorin, C.; Delchambre, E.; Desgrange, C.; Guilhem, D.; Messina, P.; Roche, H.

    2004-01-01

    An imaging spectrometer using a sapphire prism as dispersing element has been conceived at Tore Supra for the spectral range of 1 - 4 μm. It measures simultaneously at various wavelengths the temperature on distributed high heat-flux elements under plasma impact with 36 optical fibres, 4 of which are ZrF 4 fibres. It employs an InSb focal plane array detector (256*320 pixels) behind a silicon filter and a ZnS window yielding a dynamic range of 200 to 1500 deg C with 20 ms temporal resolution. The fibre transmission and the spatial variation of gain and background of the camera are calibrated using a light source with integrating sphere. With a black body source one determines the non linearity of the average gain and controls its stability during operation. The spectral dispersion of about 30 nm/pixel is determined with interference filters and controlled with a spectral lamp. The measurements at various wavelengths allow to determine the temperature distribution in the held of view. (author)

  16. Lower hybrid wave coupling in Tore Supra through multijunction launchers

    International Nuclear Information System (INIS)

    Litaudon, X.; Bibet, P.; Goniche, M.; Bergerby, G.; Bizarro, J.P.; Capitain, J.J.; Hoang, G.T.; Magne, R.; Moreau, D.; Peysson, Y.; Rax, J.M.; Rey, G.; Tonon, G.

    1991-01-01

    The TORE SUPRA Lower Hybrid Current Drive experiments (8 MW/ 3.7GHz) use large phased waveguide arrays (4 rows of 32 waveguides for each of the two grills) to couple the waves to the plasma. These launchers are based on the Multijunction principle which allows them to be quite compact but needs to be fully assessed for the design of efficient multi-megawatt antennas in NET/ITER. Extensive coupling measurements have been performed to study the Radio-Frequency characteristics of the plasma loaded multijunction antennas. The experimental data have been related to the output of the linear coupling theory which, in its advanced stage, takes into account the specific features of the compact launchers. The measurements, scattering matrices and power reflection coefficients, are in perfect agreement with the theoretical simulations performed with the measured edge plasma density. Our analysis leads to the determination of the n parallel radiated spectra. We demonstrate that the n parallel flexibility is obtained in a large range of edge plasma densities (or antenna positions) while preserving an optimum behaviour of the antenna. Finally, the Multijunction launcher has proved to be able to transmit high RF powers since power densities up to 45MW/m 2 have been reached with good linear coupling characteristics and spectrum control

  17. Particle exhaust studies in Tore Supra with a pump limiter

    International Nuclear Information System (INIS)

    Klepper, C.C.; Haste, G.R.; Horton, L.D.; Mioduszewski, P.K.; Uckan, T.; Bonnel, P.; Bruneau, J.L.; Chatelier, M.; Gil, C.; Grisolia, C.; Loarer, T.; Martin, G.; Pegourie, B.; Rodriguez, L.; Watkins, J.G.

    1990-01-01

    The aim of the Tore Supra pump limiter program is to study particle exhaust with a pump limiter system in long-pulse discharges with continuous pellet fueling and strong auxiliary heating. The pump limiter system consists of six vertical modules, located at the bottom of the machine, and one horizontal module at the outer midplane. The results presented here were obtained with the horizontal module only. This module was equipped with two titanium pumps with a total pumping speed of 100000 L/s. The instrumentation of the limiter included pressure gauges, a residual gas analyzer, Langmuir probes, a spectrometer viewing the neutralizer plate for H α and impurity measurements, and water calorimeters. All diagnostics have been commissioned and are operational. Initial results were obtained in low-density discharges, with no gas puffing during the shot. While only a modest effect on the plasma density was observed, large exhaust fluxes were measured in the pump limiter. The most likely source of this gas was outgassing of the graphite walls. Straightforward particle balance between the plasma efflux and the pump limiter exhaust, as applied in previous pump limiter experiments, did not apply. The core plasma and the edge plasma seemed to be largely decoupled and a multi-layer model is being developed to explain the experimental results. (orig.)

  18. Test of a model coil of TORE SUPRA

    International Nuclear Information System (INIS)

    Aymar, R.; Claudet, G.; Disdier, F.; Hamelin, J.; Libeyre, P.; Mayaux, C.; Meuris, C.; Parain, J.; Torossian, A.

    1980-10-01

    Inside the qualifying test programme, supporting the 'Tore Supra' Tokamak design, a reduced scale model of coil was fabricated by an industrial firm and fully tested. This model coil is provided with the same features as those retained for the complete magnet and is built according to the same design; in particular the Nb-Ti mixed matrix monolithic conductor is cooled by a pressurized superfluid helium bath, supplied from a model of the envisaged complete cryogenic system. Three main objectives have been assigned to this test: operation of the cryogenic system, stability of the superconductor winding under high mechanical stresses, mainly shear, and simulation of coil quench conditions. For this purpose, the model coil (outside bore 0.8 m) is located inside a 4 T magnet, an hydraulic jack applies a 1 MN force along a coil diameter. Operation of the model coil has been found highly stable, under the conditions of applied field and forces, a coil transition can be induced by an electrical heater only when the superfluid bath temperature is close to Tlambda. The 1.8 K cryogenic system provides a useful calorimetric measure of total losses induced inside the winding; its operation has been quite simple and reliable, permitting a sure extrapolation to a much larger size

  19. Towards high-power long-pulse operation on Tore Supra

    International Nuclear Information System (INIS)

    2000-01-01

    The Tore Supra tokamak was given the main mission to investigate the route towards long pulse plasma discharges. This includes the problem of heat exhaust and particle control (via the development of high-performance plasma facing components), and in parallel the physics of fully non inductive discharges and its optimization with respect to the confinement. Tore Supra is thus equipped with a superconducting toroidal magnet (maximum magnetic field on axis 4.5T), a full set of actively cooled plasma facing components (PFC), and a heating and current drive capability based on high power RIF systems connected to actively cooled antennas. The encouraging results already obtained, as well as recent progress in PFC, allowed us to envisage a significant improvement in the heat exhaust capability of Tore Supra. The so-called CIEL-project consists in a complete upgrade of the inner chamber of Tore Supra, planned to be installed during the year 2000. The present paper deals with the experimental and modeling activity linked to the preparation of the long-pulse high-power discharges using the present Tore Supra equipment: heating and current drive scenarios, power coupling, confinement and transport studies, discharge control... An overview of the results obtained in that field is presented, as well as the progress required in the coming years, and the expected performance, for the CIEL phase, in terms of current drive and confinement. (author)

  20. Towards operations on Tore Supra of an ITER relevant inspection robot and associated processes

    International Nuclear Information System (INIS)

    Gargiulo, L.; Cordier, J.J.; Friconneau, J.P.; Grisolia, C.; Palmer, J.D.; Perrot, Y.; Samaille, F.

    2007-01-01

    The aim of the project is to demonstrate on Tore Supra the reliability of a multi-purpose in-vessel remote handling inspection system using a long reach, limited payload carrier. The robot prototype is fully representative of the deployment carrier system that could be required on ITER. The demonstration on Tore Supra will help in the understanding of operation issues that could occur in the tokamak vacuum vessel equipped of actively cooled components. The viewing process that is currently under development will allow close inspection of the Tore Supra plasma facing components that are representative of the ITER divertor targets in terms of confined environment and identification of possible tiles failure of CFC carbon tiles. One of the other potential inspection processes that is foreseen to be tested using the AIA carrier in Tore Supra is the laser ablation system of the CFC armour. It could be fully relevant for the ITER wall detritiation issues. Such process can be simulated on Tore Supra through the deuterium inventory under long-time plasma discharges. The in situ leakage localisation of a damaged plasma facing component is also one of the major ITER maintenance challenges that could use remote handling inspection tools

  1. Towards operations on Tore Supra of an ITER relevant inspection robot and associated processes

    Energy Technology Data Exchange (ETDEWEB)

    Gargiulo, L. [Association Euratom-CEA, DSM/Departement de Recherche sur la Fusion Controlee, CEA/Cadarache, F-13108 Saint Paul Lez Durance Cedex (France)], E-mail: laurent.gargiulo@cea.fr; Cordier, J.J. [Association Euratom-CEA, DSM/Departement de Recherche sur la Fusion Controlee, CEA/Cadarache, F-13108 Saint Paul Lez Durance Cedex (France); Friconneau, J.P. [CEA-LIST Robotics and Interactive Systems Unit, BP6 F-92265 Fontenay aux Roses Cedex (France); Grisolia, C. [Association Euratom-CEA, DSM/Departement de Recherche sur la Fusion Controlee, CEA/Cadarache, F-13108 Saint Paul Lez Durance Cedex (France); Palmer, J.D. [EFDA CSU, Max-Planck-Institut fuer Plasma Physik Boltzmannstr. 2, D-85748 Garching (Germany); Perrot, Y. [CEA-LIST Robotics and Interactive Systems Unit, BP6 F-92265 Fontenay aux Roses Cedex (France); Samaille, F. [Association Euratom-CEA, DSM/Departement de Recherche sur la Fusion Controlee, CEA/Cadarache, F-13108 Saint Paul Lez Durance Cedex (France)

    2007-10-15

    The aim of the project is to demonstrate on Tore Supra the reliability of a multi-purpose in-vessel remote handling inspection system using a long reach, limited payload carrier. The robot prototype is fully representative of the deployment carrier system that could be required on ITER. The demonstration on Tore Supra will help in the understanding of operation issues that could occur in the tokamak vacuum vessel equipped of actively cooled components. The viewing process that is currently under development will allow close inspection of the Tore Supra plasma facing components that are representative of the ITER divertor targets in terms of confined environment and identification of possible tiles failure of CFC carbon tiles. One of the other potential inspection processes that is foreseen to be tested using the AIA carrier in Tore Supra is the laser ablation system of the CFC armour. It could be fully relevant for the ITER wall detritiation issues. Such process can be simulated on Tore Supra through the deuterium inventory under long-time plasma discharges. The in situ leakage localisation of a damaged plasma facing component is also one of the major ITER maintenance challenges that could use remote handling inspection tools.

  2. Implementation of FCI heating system to the control system of Tore-Supra

    International Nuclear Information System (INIS)

    Wisniewski, S.

    2001-11-01

    This report presents the implementation of the ion cyclotron resonance heating system (FCI) to the instrumentation and control system of the Tore-Supra tokamak. The new plasma heating system involves 3 antennas delivering 12 MW that are required to maintain fusion reactions. This paper is divided into 8 chapters: 1) thermonuclear fusion and Tore-Supra tokamak; 2) hardware system around Tore-Supra, in this chapter the control system and the data acquisition and processing systems are presented; 3) functional analysis, this analysis defines the different needs concerning timing and pilot-controlling, a preliminary proposition of hardware equipment is made; 4) operating modes of FCI; 5) communication within the control system network; 6) communication with the supervisory system of the power stations; 7) management of data exchange with SMX generators; and 8) control of the rate of stationary waves during the injection of power into the plasma

  3. Cherenkov-type diamond detectors for measurements of fast electrons in the TORE-SUPRA tokamak

    International Nuclear Information System (INIS)

    Jakubowski, L.; Sadowski, M. J.; Zebrowski, J.; Rabinski, M.; Malinowski, K.; Mirowski, R.; Lotte, Ph.; Gunn, J.; Pascal, J-Y.; Colledani, G.; Basiuk, V.; Goniche, M.; Lipa, M.

    2010-01-01

    The paper presents a schematic design and tests of a system applicable for measurements of fast electron pulses emitted from high-temperature plasma generated inside magnetic confinement fusion machines, and particularly in the TORE-SUPRA facility. The diagnostic system based on the registration of the Cherenkov radiation induced by fast electrons within selected solid radiators is considered, and electron low-energy thresholds for different radiators are given. There are some estimates of high thermal loads, which might be deposited by intense electron beams upon parts of the diagnostic equipment within the TORE-SUPRA device. There are some proposed measures to overcome this difficulty by the selection of appropriate absorption filters and Cherenkov radiators, and particularly by the application of a fast-moving reciprocating probe. The paper describes the measuring system, its tests, as well as some results of the preliminary measurements of fast electrons within TORE-SUPRA facility.

  4. Cherenkov-type diamond detectors for measurements of fast electrons in the TORE-SUPRA tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Jakubowski, L.; Sadowski, M. J.; Zebrowski, J.; Rabinski, M.; Malinowski, K.; Mirowski, R. [Andrzej Soltan Institute for Nuclear Studies (IPJ), Otwock-Swierk 05-400 (Poland); Lotte, Ph.; Gunn, J.; Pascal, J-Y.; Colledani, G.; Basiuk, V.; Goniche, M.; Lipa, M. [CEA, IRFM, St Paul-lez-Durance F-13108 (France)

    2010-01-15

    The paper presents a schematic design and tests of a system applicable for measurements of fast electron pulses emitted from high-temperature plasma generated inside magnetic confinement fusion machines, and particularly in the TORE-SUPRA facility. The diagnostic system based on the registration of the Cherenkov radiation induced by fast electrons within selected solid radiators is considered, and electron low-energy thresholds for different radiators are given. There are some estimates of high thermal loads, which might be deposited by intense electron beams upon parts of the diagnostic equipment within the TORE-SUPRA device. There are some proposed measures to overcome this difficulty by the selection of appropriate absorption filters and Cherenkov radiators, and particularly by the application of a fast-moving reciprocating probe. The paper describes the measuring system, its tests, as well as some results of the preliminary measurements of fast electrons within TORE-SUPRA facility.

  5. Study of the chemical sputtering in Tore-Supra

    International Nuclear Information System (INIS)

    Cambe, A.

    2002-01-01

    The work presented in this thesis focuses on the interactions between energetic particles coming from thermonuclear plasma and the inner components of a fusion machine. This interaction induces two major problems: erosion of the wall, and tritium retention. This report treats the erosion of carbon based materials. The first part is devoted to chemical sputtering, that appears to be the principal erosion mechanism, compared to physical sputtering and radiation enhanced sublimation that both can be limited. Chemical sputtering has been studied in situ in the tokamak Tore-Supra for ohmic and lower hybrid (LH) heated discharges, by means of mass spectrometry and optical spectroscopy. We have shown that it is necessary to take into account both methane and heavier hydrocarbons (C 2 D x and C 3 D y ) in the determination of the chemical sputtering yield. It is found that for the ohmic discharges, the sputtering yield of CD 4 (Y CD4 ) is highly flux (φ) dependent, showing a variation of the form: Y CD4 ∝ φ -0.23 . The experimental study also reveals that an increase of the surface temperature induces an augmentation of Y CD4 . The interpretation and the modelling of the experimental results have been performed with a Monte Carlo code (BBQ. In the second part of this work, we have developed and installed an infrared spectroscopy diagnostic in the 0.8-1.6, μm wavelength range dedicated to the measurement of surface temperature, and the identification of atomic and molecular lines emitted during plasma/wall interactions. In the third part, we present the feasibility study of an in situ tungsten deposition process at low temperature(<80 deg C) in order to suppress the chemical sputtering. This study shows that, with this method call Plasma Assisted Chemical Vapor Deposition (PACVD), we are able to coat the whole inner vessel of a tokamak with 1 μm of tungsten. (author)

  6. Major progress on tore supra toward steady state operation of tokamaks

    International Nuclear Information System (INIS)

    Saoutic, Y.

    2003-01-01

    During winter 2000-2001, a major upgrade of the internal components of Tore Supra has been completed that increased the heat extraction capability to 25 MW in steady state. Operating Tore Supra in this new configuration has produced a wealth of new results. The highlights of the 2002 long duration discharges campaign are: 4 minutes 25 seconds long discharges with an integrated energy of 0.75 GJ, which is three time higher than the old Tore Supra world record; recharge of the primary transformer by Lower Hybrid Current Drive (LHCD) for about 1 minute; 4 minutes long LHCD pulses; 1 minute long Ion Cyclotron Resonant Heating (ICRH) pulse (0.11 GJ of ICRH injected energy). Beyond the quantitative step, significant qualitative progress in the steady state nature of the discharge has been accomplished: contrary to the situation in the old Tore Supra configuration, the plasma density is perfectly controlled by active pumping over the overall shot duration. The duration of Tore Supra discharges is sufficient to allow the complete diffusion of the resistive current. Surprising new physics is revealed in such discharges when approaching zero loop voltage. Slow central electron temperature oscillations have been observed in a variety of situations. Such oscillations are not likely to be linked to any MHD instabilities and probably results from an interplay between current profile shape, LHCD power deposition and transport. Analysis of the temperature gradient in the core region shows a very interesting behaviour and the normalised temperature gradient length is compared to the critical thresholds. Finally, the performance of heating and current drive systems and the observations made of the interior of Tore Supra after the long duration discharges campaign are reported. (author)

  7. Towards operations on Tore Supra of an ITER relevant inspection robot and associated processes

    International Nuclear Information System (INIS)

    Laurent Gargiulo, L.; Cordier, J.-J.; Samaille, F.; Grisolia, Ch.; Perrot, Y.; Olivier, D.; Friconneau, J.-P.; Palmer, J.

    2006-01-01

    The aim of the project is to demonstrate on Tore Supra the reliability of a multi-purpose in-vessel Remote Handling inspection system using a long reach, limited payload carrier. This project called AIA (Articulated Inspection Arm) is currently being developed at CEA under a European EFDA work program. The paper describes the detailed design, the manufacturing processes and the results of the first module test campaign in the CEA Tore Supra ME60 facility, at representative vacuum, temperature and nominal loading conditions. The second part of this work that is reported in the paper, concerns the description of the whole integration of the device on the Tore Supra tokamak that is foreseen to be operated on Tore Supra early 2007. The deployer system and the 10 m long storage vacuum vessel are presented. The robot prototype is fully representative of the deployment carrier system that could be required on ITER. The demonstration on Tore Supra will help in the understanding of operation issues that could occur in the tokamak vacuum vessel equipped of actively cooled components. The viewing process that is currently under development is presented in the paper. It will allow close inspection of the Tore Supra Plasma Facing Components that are representative of the ITER divertor targets in terms of confined environment and identification of possible tiles failure of CFC carbon tiles. Such viewing process could be used on ITER during the early stage of operation under a limited radiation level. The AIA technology is also showing promising potential for generic application in alternative systems for ITER. The feasibility study for viewing inspection of the beam line components in the neutral beam test facility is presented. One of the other potential inspection processes that is foreseen to be tested using the AIA carrier in Tore Supra is the laser ablation system of the CFC armour. It could be fully relevant for the ITER wall detritiation issues. Such process can be

  8. Validation of the LH antenna code ALOHA against Tore Supra experiments

    International Nuclear Information System (INIS)

    Hillairet, J.; Ekedahl, A.; Kocan, M.; Gunn, J. P.; Goniche, M.

    2009-01-01

    Comparisons between ALOHA code predictions and experimental measurements of reflection coefficients for the two different Lower Hybrid Current Drive (LHCD) antennas (named C2 and C3) in Tore Supra are presented. A large variation of density in front of the antennas was obtained by varying the distance between the plasma and the antennas. Low power ( 2 ) was used in order to avoid non-linear effects on the wave coupling. Results obtained with ALOHA are in good agreement with the experimental measurements for both Tore Supra antennas and show that ALOHA is an efficient LH predictive tool.

  9. Spatially resolved charge exchange flux calculations on the Toroidal Pumped Limiter of Tore Supra

    International Nuclear Information System (INIS)

    Marandet, Y.; Tsitrone, E.; Boerner, P.; Reiter, D.; Beaute, A.; Delchambre, E.; Escarguel, A.; Brezinsek, S.; Genesio, P.; Gunn, J.; Monier-Garbet, P.; Mitteau, R.; Pegourie, B.

    2009-01-01

    A spatially resolved calculation of the charge exchange particle and energy fluxes on the Toroidal Pumped Limiter (TPL) of Tore Supra is presented, as a first step towards a better understanding and modelling of carbon erosion, migration, as well as deuterium codeposition and bulk diffusion of deuterium in Tore Supra. The results are obtained with the EIRENE code run in a 3D geometry. Physical and chemical erosion maps on the TPL are calculated, and the contribution of neutrals to erosion, especially in the self-shadowed area, is calculated.

  10. Ion Temperature Measurements in the Tore Supra Scrape-Off Layer Using a Retarding Field Analyzer

    International Nuclear Information System (INIS)

    Kocan, M.; Gunn, J.P.; Pascal, J.Y.; Gauthier, E.

    2010-01-01

    The retarding field analyzer (RFA) is one of the only widely accepted diagnostics for measuring the ion temperature T i )in the tokamak scrape-off layer. An overview of the outstanding RFA performance over ten years of operation in Tore Supra tokamak is given and the validation of T i measurements is addressed. The RFA measurements in Tore Supra are found to be well reproducible. The ion-to-electron temperature ratio is higher than one at low-to-moderate ion-electron collisionality regime and converges to unity at high collisionality regime. (authors)

  11. Steady-state operation of tokamaks: Key physics and technology developments on Tore Supra

    International Nuclear Information System (INIS)

    Jacquinot, J.

    2005-01-01

    Important technological and physics issues related to long pulse operation required for a reactor are now being addressed in Tore Supra. experimental results in conditions where all the plasma facing components are actively cooled during pulses exceeding six minutes. Important physics issues related to continuous operation are observed in non inductively driven plasmas. (author)

  12. Radio frequency additional heating systems issues for the TORE-SUPRA WEST project

    NARCIS (Netherlands)

    Guilhem, D.; Argouarch, A.; Bernard, J.M.; Bouquey, F.; Colas, L.; Delpech, L.; Durodié, F.; Ekedahl, A.; Helvoirt, J.; Hillairet, J.; Joffrin, E.; Litaudon, X.; Magne, R.; Milanesio, D.; Moerel, J.; Mollard, P.; Wittebol, E.; Achard, J.; Armitano, A.; Berger-By, G.; Charabot, N.; Goniche, M.; Jacquot, J.; Lombard, G.; Prou, M.; Traisnel-Corbel, E.; Volpe, R.; Vulliez, K.

    2013-01-01

    This year TORE-SUPRA celebrated its 25 years of operation. During this long time a number of technologies have been developed [1]. First of all it was mandatory to develop reliable superconducting magnets at ∼ - 4 K, with superfluid helium as efficient coolant. For the production of steady state

  13. Lower-hybrid wave coupling and impurity generation in Tore Supra

    International Nuclear Information System (INIS)

    Goniche, M.; Litaudon, X.; Guilhem, D.; Hutter, T.; Beaumont, B.; Froissart, P.; Rey, G.; Saoutic, B.

    1995-01-01

    This document deals with the high power coupling of Lower Hybrid (LH) waves in Tore Supra. The effect of the plasma shape is described, together with LH coupling in ion-cyclotron resonance experiments. It appears that plasma modifications can alter the LH coupling. Eventually, the effect of LH power on thermal load and impurity generation is presented. (TEC). 3 refs., 3 figs

  14. First lower hybrid current drive experiments at 3.7 GHz in Tore Supra

    International Nuclear Information System (INIS)

    Tonon, G.; Goniche, M.; Moreau, D.

    1989-01-01

    The results of electromagnetic waves injection in the Tore Supra plasma, at a frequency of 3.7 GHz, are reported. The process is applied for current generation and plasma heating, through Landau damping on the electron population. The experimental set-up is described. The lower hybrid current drive experiments in Tore Supra are carried out under the following conditions: major and minor radii of the plasma are respectively 2.37 m and 0.77 m and the toroidal magnetic field is 1.8 Teslas. A multijunction-grill composed of 128 waveguides is applied. Up to 1.25 MW of rf power is injected in Tore Supra, after less than 30 plasma shots. The results lead to the conclusion that the coupling, not yet optimized, is good enough for safe klystron operation with no circulator. The measured value RIp P RF -1 (δV L /V L ) obtained on Tore Supra (Bt = 1.8 T) is closed to one observed on PETULA-B (Bt = 2.75 T) at the same frequency and density

  15. Upgraded ECE radiometer on the Tore Supra Tokamak

    International Nuclear Information System (INIS)

    Segui, J.L.; Molina, D.; Goniche, M.; Maget, P.; Udintsev, V.S.; Kraemer-Flecken, A.

    2004-01-01

    An upgraded 32-channel heterodyne radiometer, 1 GHz spaced, is used on the Tore-Supra tokamak to measure the electron cyclotron emission (ECE) in the frequency range 78-110 GHz for the ordinary mode (O1) and 94-126.5 GHz for the extraordinary mode (X2). From now radial resolution is essentially limited by ECE relativistic effects related to electron temperature and density, not by the channels frequency spacing. For example, this leads to precise electron temperature mapping during magneto hydrodynamic activities (MHD). In the equatorial plane, we use a dual polarisation Gaussian optics lens antenna. It has low spreading and a perpendicular line-of-sight that gives ECE measurements very low refraction and Doppler effects. Assuming that the plasma is a black body and there is no overlap between ECE harmonics, one can deduce the electron temperature profile by using the first harmonic ordinary mode (O1) or the second harmonic extraordinary mode (X2). The principle radio frequency emitter (RF) has its frequencies down shifted into intermediary frequencies (IF) that span from 2 to 18 GHz in the single side band mode (SSB). It is amplified by low noise IF amplifiers before forming channels. A separate O/X mode RF front-end allows the use of an IF electronic mode selector. This gives the potentiality of simultaneous O/X mode measurements in the 94-110 GHz. RF and IF filters reject the gyrotron frequency (118 GHz) in order to perform electron temperature measurements during electron cyclotron resonance heated plasmas. A precise absolute spectral calibration is performed outside the tokamak vacuum vessel by using a 600 deg C black body hot source, a double coherent digital signal averaging (trigger, turn and clock) on the waveform generated by a mechanical chopper, and a simulated tokamak window. The use of differential electronics and strong electromagnetic shielding improves also the calibration precision. The fast and slow data acquisition systems are free of aliasing

  16. Upgraded ECE radiometer on the Tore Supra Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Segui, J.L.; Molina, D.; Goniche, M.; Maget, P.; Udintsev, V.S. [Association Euratom-CEA, Centre d' Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Antar, G.Y. [Center for Energy Research, UCSD, La Jolla CA (United States); Kraemer-Flecken, A. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Plasmaphysik

    2004-07-01

    An upgraded 32-channel heterodyne radiometer, 1 GHz spaced, is used on the Tore-Supra tokamak to measure the electron cyclotron emission (ECE) in the frequency range 78-110 GHz for the ordinary mode (O1) and 94-126.5 GHz for the extraordinary mode (X2). From now radial resolution is essentially limited by ECE relativistic effects related to electron temperature and density, not by the channels frequency spacing. For example, this leads to precise electron temperature mapping during magneto hydrodynamic activities (MHD). In the equatorial plane, we use a dual polarisation Gaussian optics lens antenna. It has low spreading and a perpendicular line-of-sight that gives ECE measurements very low refraction and Doppler effects. Assuming that the plasma is a black body and there is no overlap between ECE harmonics, one can deduce the electron temperature profile by using the first harmonic ordinary mode (O1) or the second harmonic extraordinary mode (X2). The principle radio frequency emitter (RF) has its frequencies down shifted into intermediary frequencies (IF) that span from 2 to 18 GHz in the single side band mode (SSB). It is amplified by low noise IF amplifiers before forming channels. A separate O/X mode RF front-end allows the use of an IF electronic mode selector. This gives the potentiality of simultaneous O/X mode measurements in the 94-110 GHz. RF and IF filters reject the gyrotron frequency (118 GHz) in order to perform electron temperature measurements during electron cyclotron resonance heated plasmas. A precise absolute spectral calibration is performed outside the tokamak vacuum vessel by using a 600 deg C black body hot source, a double coherent digital signal averaging (trigger, turn and clock) on the waveform generated by a mechanical chopper, and a simulated tokamak window. The use of differential electronics and strong electromagnetic shielding improves also the calibration precision. The fast and slow data acquisition systems are free of aliasing

  17. Controlled thermonuclear fusion: Tore Supra back bone of the EURATOM-CEA programme for the next ten years

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    The decision to grant priority operation status to the French Tokamak Tore Supra will make it possible to start on the construction of this large machine and to bring together at the Cadarache Nuclear Study Centre all the facilities of the CEA for their research on fusion by magnetic confinement. The work is scheduled to begin in 1982 and to last until 1985. The financing is indicated and Tore Supra is briefly described [fr

  18. Analyses of metallic first mirror samples after long term plasma exposure in Tore Supra

    International Nuclear Information System (INIS)

    Lipa, M.; Schunke, B.; Gil, Ch.; Bucalossi, J.; Voitsenya, V.S.; Konovalov, V.; Vukolov, K.; Balden, M.; De Temmerman, G.; Oelhafen, P.; Litnovsky, A.; Wienhold, P.

    2006-01-01

    Metallic mirrors are foreseen in ITER diagnostic systems as optical elements directly viewing the plasma radiation. In the frame of an EFDA contract, metallic mirror samples have been exposed for long pulse plasma discharges in Tore Supra (TS) in order to investigate surface modifications caused by erosion and re-deposition processes. Three different materials have been selected: mono-crystalline molybdenum (mc-Mo), polycrystalline stainless steel (SS) and copper (Cu). The mc-Mo samples showed after TS exposure almost no surface roughness modifications and the lowest net-erosion. A slight reflectivity reduction, most pronounced in the near UV, is attributed to light absorption in a thin carbon deposit. Cu mirrors showed by far the highest surface roughness, erosion and diffusive reflectivity. Comparative laboratory glow discharge experiments with virgin reference samples and numerical simulations of erosion/deposition confirm the dominant contribution of conditioning procedures to erosion of mirrors exposed (without shutter protection) in Tore Supra

  19. Carbon source from the toroidal pumped limiter during long discharge operation in Tore Supra

    International Nuclear Information System (INIS)

    Dufour, E.; Brosset, C.; Lowry, C.; Bucalossi, J.; Chappuis, P.; Corre, Y.; Desgranges, C.; Guirlet, R.; Gunn, J.; Loarer, T.; Mitteau, R.; Monier-Garbet, P.; Pegourie, B.; Reichle, R.; Thomas, P.; Tsitrone, E.; Hogan, J.; Roubin, P.; Martin, C.; Arnas, C.

    2005-01-01

    A better understanding of deuterium retention mechanisms requires the knowledge of carbon sources in Tore-Supra. The main source of carbon in the vacuum vessel during long discharges is the toroidal pumped limiter (TPL). This work is devoted to the experimental characterisation of the carbon source from the TPL surface during long discharges using a visible spectroscopy diagnostic. Moreover, we present an attempt to perform a carbon balance over a typical campaign and we discuss it with regards to the deuterium in-vessel inventory deduced from particle balance and the deuterium content of the deposited layers. The study shows that only a third of the estimated deuterium trapped in the vessel is trapped in the carbon deposits. Thus, in the present state of our knowledge and characterisation of the permanent retention, one has to search for mechanisms other than co-deposition to explain the deuterium retention in Tore Supra. (A.C.)

  20. Conceptual design of a high heat flux toroidal pumped limiter for Tore Supra

    International Nuclear Information System (INIS)

    Doceul, L.; Schlosser, J.; Chappuis, Ph.; Chatelier, M.; Cocat, J.P.; Deck, C.; Faisse, F.; Grosman, A.; Mitteau, R.; Tonon, G.

    1994-01-01

    In the frame of the Tore-Supra upgrade, where it is planned to inject up to 25 MW during a time up to 1000 s, a complete toroidal pumped limiter covered of CFC (Carbon Fiber Composite) tiles is being designed. The design is based on the important experience gained from the operation on Tore Supra of actively cooled plasma facing components and pumped limiters. This toroidal limiter covers 7.5 m 2 of the bottom part of the inner vessel and is composed of 576 elementary components. Each element is built from dispersion strengthened copper (DSCu) protected by brazed CFC flat tiles and cooled by pressurised water at 150 deg C. This limiter is designed to sustain 15 MW of convective power. (author) 7 refs.; 5 figs., 3 tabs

  1. First results of the Tore Supra ITER like ICRF antenna prototype

    International Nuclear Information System (INIS)

    Vulliez, K.; Bosia, G.; Bremond, S.; Agarici, G.; Beaumont, B.; Lombard, G.; Millon, L.; Mollard, P.; Volpe, D.

    2005-01-01

    The project of an ITER-like (IL) ion cyclotron (IC) prototype antenna was initiated in mid 2002 in Cadarache, to assess the operational characteristics of the IL scheme in a Tore Supra (TS)-sized array. The prototype was developed by modifying an existing Tore Supra resonant double loop (RDL) antenna. This strategy, chosen to reduce cost and manufacturing time, allowed the completion of the array construction at the end of 2003. The array was installed on TS in January 2004, at the beginning of the new experimental campaign. After a few comments on the design, the paper reports results on low-power characterisation, high-power commissioning and preliminary tests on TS plasmas, prior to the array dis-assembly for inspection

  2. Experience gained from high heat flux actively cooled PFCs in Tore Supra

    International Nuclear Information System (INIS)

    Grosman, A.; Bayetti, P.; Brosset, C.; Bucalossi, J.; Cordier, J.J.; Durocher, A.; Escourbiac, F.; Ghendrih, Ph.; Guilhem, D.; Gunn, J.; Loarer, T.; Lipa, M.; Mitteau, R.; Pegourie, B.; Reichle, R.; Schlosser, J.; Tsitrone, E.; Vallet, J.C.

    2005-01-01

    The implementation of actively cooled high heat flux plasma facing components (PFCs) is one of the major ingredients required for operating the Tore Supra tokamak with very long pulses. A pioneering activity has been developed in this field from the very beginning of the device operation that is today culminating with the routine operation of an actively cooled toroidal pumped limiter (TPL) capable to sustain up to 10 MW/m 2 of nominal convected heat flux. Technical information is drawn from the whole development up to the industrialisation and focuses on a number of critical issues, such as bonding technology analysis, manufacture processes, repair processes, destructive and non-destructive testing. The actual experience in Tore Supra allows to address the question of D retention on carbon walls. Redeposition on surfaces without plasma flux is suspected to cause the final 'burial' of about half of the injected gas during long discharges

  3. From eroded material to dust: An experimental evaluation of the mobilised dust production in Tore Supra

    International Nuclear Information System (INIS)

    Grisolia, C.; Rosanvallon, S.; Loarte, A.; Sharpe, P.; Arnas, C.

    2009-01-01

    In a fusion reactor like ITER, in-vessel materials are subjected to interactions with the plasma. One of the main consequences of these plasma-material interactions is the creation of co-deposited layers especially with Beryllium and Carbon based materials. Due to internal stresses, part of these layers can crack leading to micro particle creation. The purpose of the following paper is to review the tokamak operation processes that lead to the erosion of the bulk material and then to layer creation. The proportion of these layers that are converted into micro particles will be evaluated in the case of Tore Supra experiments. For Tore Supra, this conversion factor (Cd) is close to 7-8% comparable to the current ITER retained value of 10%. In the second part of the papers, diagnostics which can be used to constraint the Cd value are proposed.

  4. Management of water leaks on Tore Supra actively cooled fusion device

    International Nuclear Information System (INIS)

    Hatchressian, J.C.; Gargiulo, L.; Samaille, F.; Soler, B.

    2005-01-01

    Up to now, Tore Supra is the only fusion device fully equipped with actively cooled Plasma Facing Components (PFCs). In case of abnormal events during a plasma discharge, the PFCs could be submitted to a transient high power density (run away electrons) or to a continuous phenomena as local thermal flux induced by trapped suprathermal electrons or ions). It could lead to a degradation of the PFC integrity and in the worst case to a water leak occurrence. Such water leak has important consequence on the tokamak operation that concerns PFCs themselves, monitoring equipment located in the vacuum vessel or connected to the ports as RF antennas, diagnostics or pumping systems. Following successive water leak events (the most important water leak, that occurred in September 2002, is described in the paper), a large feedback experience has been gained on Tore supra since more than 15 years that could be useful to actively cooled next devices as W7X and ITER. (authors)

  5. A long-period analog integrator for magnetic measurements in Tore Supra

    International Nuclear Information System (INIS)

    Prou, M.; Barth, E.; Couturier, P.; Ouvrier-Buffet, P.

    1998-01-01

    A new analog integrator, called 'Integrateur 2000', has been developed for precise integration over long periods for the magnetic signals of Tore Supra with the aim of 1000 s discharges for the CIEL project. This new integrator is already in routine use for the present pulse lengths of up to 200 s in T-S, and tests have been carried out up to 1000 s with less than 2 mV of drift. (author)

  6. Improved confinement with ion cyclotron hydrogen minority heating on Tore Supra

    International Nuclear Information System (INIS)

    Hoang, G.T.; Monier-Garbet, P.; Aniel, T.; Bourdelle, C.; Eriksson, L.G.; Garbet, X.; Grisolia, C.; Platz, P.; Budny, R.V.

    1999-02-01

    Tore Supra experiments are presently devoted to study the high density and high radiation regimes with radio frequency heating. Recent results of ion cyclotron minority heating have been obtained with an improved L-mode confinement, close to ELMy H-mode, at relatively high density (up to 80% of Greenwald limit). Such a regime is very promising as possible scenario in a next step tokamak. (authors)

  7. ICRF plasma production in Tore Supra: analysis of antenna coupling and plasma properties

    International Nuclear Information System (INIS)

    Beaumont, B.; Becoulet, A.; Lyssoivan, A.

    1999-01-01

    A study of RF plasma production frequency range ω. 2ω ci has been undertaken on Tore Supra taking into account antenna coupling predictions of theory and the TEXTOR-94 database. Two scenarios for RF discharges have been tested (fixed frequency of the RF generator): operation with pure toroidal magnetic field, at standard and lower B T and operation in the magnetic configuration with a small vertical (B V ) field superimposed on B T (B V T ). (authors)

  8. TORE-SUPRA: design of thermal radiation shield at 80 K

    International Nuclear Information System (INIS)

    Aymar, R.; Cordier, J.J.; Deschamps, P.; Gauthier, A.; Perin, J.P.

    1982-09-01

    The TORE-SUPRA superconducting toroidal magnet operating at liquid helium temperature, must be protected against thermal radiation from the vessels. For this purpose, stainless steel heat shields, cooled at 80 K, are positioned between coil casings at 4.5 K and the vessels, and constitute a double stiff toroid which completely surrounds the magnet. Mockups have been manufactured to study their design and operating problems. Calculations have also been made to analyse the mechanical behaviour of these shields

  9. MHD limits in non-inductive tokamak plasmas: simulations and comparison to experiments on Tore Supra

    International Nuclear Information System (INIS)

    Maget, P.; Huysmans, G.; Ottaviani, M.; Garbet, X.; Moreau, Ph.; Segui, J.-L.; Luetjens, H.

    2008-01-01

    Non-inductive tokamak discharges with a flat or hollow current profile are prone to the triggering of large tearing modes when the minimum of the safety factor is just below a low order rational. This issue is of particular importance for discussing the optimal safety factor for MHD modes avoidance in Steady-State reactor plasmas. Different non-linear regimes of such magnetic configurations in Tore Supra are studied using the full MHD code XTOR. Numerical simulations show that the non-linear stage of the Double-Tearing Mode (DTM) is governed by the full reconnection model, but a single tearing mode in a low magnetic shear configuration can have a similar impact on the confinement. The different regimes observed experimentally are recovered in the simulations: a small amplitude (2,1) DTM for close resonant surfaces as seen in Tore Supra, a sawtooth-like behaviour of the (2,1) Double-Tearing Mode as first seen in TFTR, or a large amplitude (2,1) tearing mode that severely degrades the energy confinement, as reported in Tore Supra, JET or DIII-D. Situations where q min ≅1.5 with a stable n = 1 mode, as seen in Tore Supra longest discharges, seem to put specific constraints on the MHD model that is used. Indeed, curvature stabilisation without transport terms as could explain linear stability, but such effect vanishes in presence of heat transport. Electron diamagnetic rotation effect is investigated as a possible mechanism for n = 1 mode stabilization.

  10. The ground fault detection system for the Tore Supra toroidal pump limiter

    International Nuclear Information System (INIS)

    Zunino, K.; Cara, P.; Fejoz, P.; Hourtoule, J.; Loarer, T.; Pomaro, N.; Santagiustina, A.; Spuig, P.; Villecroze, F.

    2003-01-01

    The toroidal pump limiter (TPL) of Tore Supra is electrically insulated from the vacuum-vessel, to allow its polarization at a voltage of up to 1 kV. In order to monitor continuously the integrity of the TPL electrical insulation, an electronic diagnostic system called TPL ground fault detection system (GFDS) has been developed. The paper will report on the design and the operation experience of the GFD system and on the evolution of the TPL grounding

  11. Studies of suprathermal electron loss in the magnetic ripple of Tore Supra

    International Nuclear Information System (INIS)

    Basiuk, V.; Lipa, M.; Martin, G.; Chantant, M.; Guilhem, D.; Imbeaux, F.; Mitteau, R.; Peysson, Y.; Surle, F.

    2000-01-01

    A new prototype of protection against fast electron trapped in the magnetic ripple was installed on Tore-Supra in 1998. It was designed to support the high flux of fast electron generated by lower hybrid in the CIEL project (up to 6 MW/m 2 ) during steady state experiments. So it is actively cooled and allows a direct measurement of the energy lost in the ripple. (author)

  12. Reversed magnetic shear operation with ICRF minority heating on Tore Supra

    International Nuclear Information System (INIS)

    Hoang, G.T.; Antar, G.; Aniel, T.

    1999-01-01

    This paper reports a scenario recently investigated in Tore Supra for high density and high plasma current (Ip) operation, which allows to use the ion cyclotron resonance frequency (ICRF) minority heating only for the internal transport barrier (ITB) formation. The main aim is to perform a hollow current density profile by minimizing the edge resistive skin depth during the rapid Ip ramp-up, i-e efficient freezing of the resistive current diffusion

  13. On the role of ion heating in ICRF-heated discharges in Tore Supra

    International Nuclear Information System (INIS)

    Eriksson, L.G.; Hoang, G.; Bergeaud, V.

    2000-09-01

    The effect of bulk ion heating in Tore Supra has been investigated by studying discharges with varying concentrations of minority ions during ICRF hydrogen minority heating in Deuterium/ 4 He plasmas. As expected, the level of bulk ion heating is found to increase with the minority concentration. Higher levels of ion heating are shown to be accompanied by two significant effects: an improved energy confinement and a strong influence on the plasma rotation. (author)

  14. Experiment and Modelling of Itb Phenomena with Eccd on Tore Supra

    Science.gov (United States)

    Turco, F.; Giruzzi, G.; Artaud, J.-F.; Huysmans, G.; Imbeaux, F.; Maget, P.; Mazon, D.; Segui, J.-L.

    2009-04-01

    An extensive database of Tore Supra discharges with Internal Transport Barriers (ITBs) has been analysed. A tight correlation has been found, which links the central value of q and the creation of an ITB, while no correspondence with magnetic shear or qmin values can be inferred. In the case of incomplete transition to ITB (O-regime), modelling in presence of ECCD confirms the experimental observations about triggering/stopping and amplifying the oscillations.

  15. The response of the Tore Supra edge plasma to supersonic pulsed gas injection

    Czech Academy of Sciences Publication Activity Database

    Pánek, Radomír; Gunn, J. P.; Bucalossi, J.; Ďuran, Ivan; Geraud, A.; Hron, Martin; Loarer, T.; Pégourié, B.; Stöckel, Jan; Tsitrone, E.

    337-339, č. 16 (2005), s. 530-534 ISSN 0022-3115. [Plasma Surface Interactions /16./. Portland, 24.5.2005-28.5.2005] R&D Projects: GA ČR(CZ) GP202/03/P062 Institutional research plan: CEZ:AV0Z20430508 Keywords : Edge plasma * Gas injection and fuelling * probes * Plasma flow * Tore Supra Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.414, year: 2005

  16. Design and manufacture of the large poloidal coils for TORE SUPRA

    International Nuclear Information System (INIS)

    Calmels, C.; Leloup, C.; Rijnoudt, E.; Ane, J.M.; Chassain, P.; Giaccheto, A.

    1984-01-01

    After a short summary of the main features of the TORE SUPRA long pulse Tokamak poloidal field system, the manufacture process of the six larger coils is described. The hollow conductor copper cross section is almost equal to the water channel one so that the coils can withstand more than 30 s pulses at full power. The main difficulties arise from the exceptional size of these one piece coils which are up to 9 meters in diameter. (author)

  17. Articulated inspection arm for ITER, a demonstration in the Tore Supra tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Cordier, J.J.; Gargiulo, L.; Grisolia, C.; Samaille, F. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Friconneau, J.P.; Perrot, Y. [CEA Fontenay-aux-Roses, LIST Robotics and Interactive Systems Unit, 92 (France); Palmer, J.D. [Max-Planck-Institut fuer Plasmaphysik Boltzmannstr.2, Garching (Germany)

    2003-07-01

    The aim of this program is to demonstrate for ITER the feasibility of an in-vessel remote handling inspection using a long reach, limited payload carrier (1 to 10 kg) for penetration of the ITER chamber through the openings. This device is dedicated to close inspection of the Plasma Facing Components (PFC). An articulated demonstrator called articulated inspection arm (AIA) has been manufactured. A feasibility study of a full AIA operation in Tore Supra was performed, taking into account ITER reference requirements. A scale one demonstration of the AIA under ITER relevant condition is feasible on Tore Supra and would give significant improvement in research results for ITER remote Handling equipment. The test of the AIA demonstrator behaviour is foreseen in 2005 in real Tokamak conditions. The paper presents the full robot concept, the results of the first test campaign, the AIA new design and its integration on Tore Supra. Several potential uses of the AIA for the in vessel components inspection are being studied such as PFC visual inspection, water loop leak testing, laser ablation for wall detritiation and carbon dust and flakes removal are foreseen as utilities to be placed at the AIA head. These various systems are described in the paper.

  18. Articulated inspection arm for ITER, a demonstration in the Tore Supra tokamak

    International Nuclear Information System (INIS)

    Cordier, J.J.; Gargiulo, L.; Grisolia, C.; Samaille, F.; Palmer, J.D.

    2003-01-01

    The aim of this program is to demonstrate for ITER the feasibility of an in-vessel remote handling inspection using a long reach, limited payload carrier (1 to 10 kg) for penetration of the ITER chamber through the openings. This device is dedicated to close inspection of the Plasma Facing Components (PFC). An articulated demonstrator called articulated inspection arm (AIA) has been manufactured. A feasibility study of a full AIA operation in Tore Supra was performed, taking into account ITER reference requirements. A scale one demonstration of the AIA under ITER relevant condition is feasible on Tore Supra and would give significant improvement in research results for ITER remote Handling equipment. The test of the AIA demonstrator behaviour is foreseen in 2005 in real Tokamak conditions. The paper presents the full robot concept, the results of the first test campaign, the AIA new design and its integration on Tore Supra. Several potential uses of the AIA for the in vessel components inspection are being studied such as PFC visual inspection, water loop leak testing, laser ablation for wall detritiation and carbon dust and flakes removal are foreseen as utilities to be placed at the AIA head. These various systems are described in the paper

  19. The Tore Supra control, computer system : six years of operation and improvements

    International Nuclear Information System (INIS)

    Journeaux, J.Y.; Badie, O.; Chatelier, E.; Hennion, F.; Lebourg, P.; Leveque, P.; Hernandez, M.; Moulin, D.

    1995-01-01

    The Tore Supra control computer system has been providing a good operation of the Tore Supra machine for six years. It controls all of the sub-systems, the continuous ones as well as the sequential ones, and the automatic operation is very efficient. The control system has been programmed by the users themselves thanks to its user-friendly qualities, in order to keep the full control and knowledge of the automatisms. Nevertheless, some improvements are now necessary. Their main principles are : to choose ergonomic and powerful tools, industrial standards, and to keep the users's participation. The whole control system will be upgraded : the automatism level as well as the display level and the communication networks. The operator's driving job is analysed as supervisory and diagnostic tasks which have an effect on the Tore Supra machine efficiency. So a very powerful driving software has been chosen and linked with an expert system, which is to be designed and implemented with the aim to give an immediate accurate and global understanding of the process and situations, in particular in case of trouble. The method is based on an artificial intelligence approach, and it exploits both the process' informations and automatisms' steps, to determine the process state, next possible states and diagnosis of the process troubles. (orig.)

  20. Numerical modelling of pump limiter biasing on TEXTOR-94 and Tore Supra

    International Nuclear Information System (INIS)

    Gerhauser, H.; Claassen, H.A.; Mank, G.; Zagorski, R.; Loarer, T.; Gunn, J.; Boucher, C.

    2002-01-01

    The two-dimensional multifluid code TECXY has been used to model the biasing (with respect to the first wall) of the toroidal belt limiter ALT-II on the tokamak TEXTOR-94 and of the new toroidal pump limiter being installed on Tore Supra tokamak in the framework of the CIEL project. It is well known that the edge flow pattern can be influenced by the poloidal electric drifts from imposing radial electric fields. The modelling with TECXY introduces imprinted bias currents in the scrape-off layer (SOL) for the case of negative (limiter) biasing, and imprinted bias potentials for the case of positive biasing. This allowed us to simulate sufficiently well the experimental I-V characteristics for either biasing of ALT-II and also reproduced the essential features and trends of the observed plasma profiles in the SOL of TEXTOR-94. For negative biasing a moderate improvement of the pumping exhaust efficiency can be achieved in the case of TEXTOR. For Tore Supra, however, only a negligible improvement of the limiter performance with biasing can be predicted, which is explained by the relatively weak drift flows in Tore Supra. (author)

  1. Engineering studies for the installation of an axi-symmetric metallic divertor in Tore Supra

    International Nuclear Information System (INIS)

    Doceul, L.; Portafaix, C.; Bucalossi, J.; Saille, A.; Bertrand, B.; Lipa, M.; Missirlian, M.; Jiolat, G.; Samaille, F.; Soler, B.

    2011-01-01

    Tore Supra (TS) has been designed to operate using technologies that allow long plasma operation (a few minutes), by means of superconducting magnets and actively-cooled high heat flux plasma facing components (PFCs). Actively cooled tungsten PFC will be used in the baffle area of the first ITER divertor. In order to validate such a technology fully (industrial manufacturing, operation with long plasma duration), the implementation of a tungsten axi-symmetric divertor in the tokamak Tore Supra has been studied . With this second major upgrade, Tore Supra should be able to address the problematic of long plasma discharges with a metallic divertor. The proposed divertor is made up of two stainless steel casings containing a copper coil winding located at the top and bottom area of the vacuum vessel. These casings are firmly maintained by connection beams and protected by PFC. This paper describes the mechanical design of this major component and its integration in TS, the associated electromagnetic and thermomechanical analysis, the manufacturing issues and finally the integration of ITER representative PFCs.

  2. The data acquisition and interlock system for Tore Supra infrared imaging

    International Nuclear Information System (INIS)

    Moulin, D.; Balorin, C.; Buravand, Y.; Caulier, G.; Ducobu, L.; Guilhem, D.; Jouve, M.; Roche, H.

    2003-01-01

    The data acquisition for the infrared measurement system on Tore-Supra is a key element in ensuring the supervision of the new actively-cooled plasma facing components of the CIEL project. It will allow us to follow the thermal evolution of components of Tore-Supra, in particular the toroidal pumped limiter (LPT) (360 deg.-15 m long) and the five additional heating launchers. When fully installed, the infrared measurement system will be composed of 12 digital 16-bit infrared cameras. They cover a 100-1200 deg.C temperature range and each picture has a definition of 320x240 pixels with a 20 ms time resolution. The objectives of the data acquisition system is real-time recording and analysis of each view element for further post-pulse analysis in order to understand the physics phenomenon and ensure the supervision of the plasma facing components and also to be part of the global feedback control system of Tore Supra

  3. Opportunist combination of electronic technologies for real time calculations in the Tore Supra Tokamak

    International Nuclear Information System (INIS)

    Barbuti, A.; Gil, C.; Pastor, P.; Spuig, P.; Vincent, B.; Volpe, D.

    2013-06-01

    The Tore Supra tokamak real-time plasma control is based on measurements coming from various diagnostics. The complexity of all the events that occur during plasma is at the origin of measurements disturbances which have to be corrected in real time in order to ensure an optimal control. The signal correction does not just mean processing but requires complex algorithms. Electronics does not only need to process and adapt electrical signals, but it has to include corrections by mathematical calculation. The FPGA (field-programmable gate array) technology, with the help of basic adapted electronics, allows integrating the entire real time calculation and digital data transmission on the network. FMC (FPGA Mezzanine Card) coupled with in-house motherboard, which is used both as the interface with Tore Supra specific systems and as the support for other signals processing options, is the perfect answer to this request. The FMC includes a FPGA, memory, Ethernet port and multiple I/O for interfacing with the motherboard and Tore Supra signals. The algorithms are developed in VHDL (Very high speed integrated circuit Hardware Description Language), parallel process management that promotes faster calculation than a common μC (Micro-controller) in one clock pulse. The flexibility, the low cost and the implementation speed allow fitting a large number of various applications in fields where no 'off-theshelf' component can be found. And more specifically, in research and experimentation, algorithms can be continuously improved or modified for new requirements. (authors)

  4. Poloidal asymmetries of flows in the Tore Supra tokamak

    Science.gov (United States)

    Vermare, L.; Hennequin, P.; Gürcan, Ö. D.; Garbet, X.; Honoré, C.; Clairet, F.; Giacalone, J. C.; Morel, P.; Storelli, A.; Tore Supra Team

    2018-02-01

    Simultaneous measurements of binormal velocity of density fluctuations using two separate Doppler backscattering systems at the low field side and at the top of the plasma show significant poloidal asymmetry. The measurements are performed in the core region between the radii 0.7 Supra tokamak. A possible generation mechanism by the ballooned structure of the underlying turbulence, in the form of convective cells, is proposed for explaining the observation of these poloidally asymmetric mean flows.

  5. Lower hybrid current drive experiments in Tore Supra

    International Nuclear Information System (INIS)

    Moreau, D.

    1991-12-01

    Two large multi junction launchers have allowed to couple up to 6 MW to the plasma. The current drive efficiency was about 2 x 10 19 Am -2 /W with LH power alone at a volume-averaged electron temperature of 1.4 keV. Experiments with combined LHCD and ion cyclotron resonant heating allowed to inject up to 7.5 MW into the plasma. The electron energy content followed fairly well the Rebut-Lallia scaling law. At n e = 1.5 x 10 19 m -3 , sawteeth were suppressed and m = 1 MHD oscillations appeared. The central electron temperature then reached 8 keV for 3.6 MW injected. LH power modulation experiments performed at n e = 4 x 10 19 m -3 showed a delayed central electron heating despite the off-axis creation of suprathermal electrons, thus ruling out the possibility of direct heating through central wave absorption. Successful pellet fueling of a partially LH driven plasma was obtained, in which 28 successive pellets could penetrate up to half radius as in ohmic discharges, with 50 to 80% of the pellet content deposited in the plasma. First attempts to combine LHCD with ergodic divertor discharges showed that, when the plasma edge was subject to a radial magnetic perturbation smaller than the ergodicity threshold, a strong stationary radiation (MARFE) was triggered, locked near the inner wall. The radiated power then amounted to 90% of the total input power with no indication of a radiative collapse

  6. Implementation of FCI heating system to the control system of Tore-Supra; Integration du systeme de chauffage FCI au sein du reseau de controle commande du Tokamak Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Wisniewski, S

    2001-11-01

    This report presents the implementation of the ion cyclotron resonance heating system (FCI) to the instrumentation and control system of the Tore-Supra tokamak. The new plasma heating system involves 3 antennas delivering 12 MW that are required to maintain fusion reactions. This paper is divided into 8 chapters: 1) thermonuclear fusion and Tore-Supra tokamak; 2) hardware system around Tore-Supra, in this chapter the control system and the data acquisition and processing systems are presented; 3) functional analysis, this analysis defines the different needs concerning timing and pilot-controlling, a preliminary proposition of hardware equipment is made; 4) operating modes of FCI; 5) communication within the control system network; 6) communication with the supervisory system of the power stations; 7) management of data exchange with SMX generators; and 8) control of the rate of stationary waves during the injection of power into the plasma.

  7. Study of the electron heat transport in Tore-Supra tokamak; Etude du transport de la chaleur electronique dans le Tokamak Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Harauchamps, E

    2004-07-01

    This work presents analytical solutions to the electron heat transport equation involving a damping term and a convection term in a cylindrical geometry. These solutions, processed by Matlab, allow the determination of the evolution of the radial profile of electron temperature in tokamaks during heating. The modulated injection of waves around the electron cyclotron frequency is an efficient tool to study heat transport experimentally in tokamaks. The comparison of these analytical solutions with experimental results from Tore-Supra during 2 discharges (30550 and 31165) shows the presence of a sudden change for the diffusion and damping coefficients. The hypothesis of the presence of a pinch spread all along the plasma might explain the shape of the experimental temperature profiles. These analytical solutions could be used to determine the time evolution of plasma density as well or of any parameter whose evolution is governed by a diffusion-convection equation. (A.C.)

  8. First plasma experiments in Tore Supra with a new generation of high heat flux limiters for RF antennas

    International Nuclear Information System (INIS)

    Agarici, G.; Beaumont, B.; Bibet, Ph.; Bremond, S.; Bucalossi, J.; Colas, L.; Durocher, A.; Gargiulo, L.; Ladurelle, L.; Lombard, G.; Martin, G.; Mollard, P.

    2000-01-01

    During the 1997 and 1998 Tore Supra shutdown, a first set of new antenna guard limiters was installed on one of the three ion cyclotron resonance heating (ICRH) antennas of Tore Supra. This limiter, which was one of the main technological studies of the 1998 campaign, was widely experimented in real plasma conditions, thus allowing the validation in situ, for the first time, of the technology of active metal casting (AMC) for plasma facing components. The huge improvement in the thermal response of the new limiter generation, compared to the old one, is shown on plasma pulses made identical in terms of antenna position and injected RF power profile. By using the infrared cameras installed inside Tore Supra and viewing the antennas front, the power density fluxes received by the carbon fibre composite (CFC) surface of the limiter were evaluated by correlation with the heat load tests made on the electrons beam facility of CEA/Framatome

  9. Infrared reflection properties and modelling of in situ reflection measurements on plasma-facing materials in Tore Supra

    International Nuclear Information System (INIS)

    Reichle, R; Desgranges, C; Faisse, F; Pocheau, C; Lasserre, J-P; Oelhoffen, F; Eupherte, L; Todeschini, M

    2009-01-01

    Tore Supra has-like ITER-reflecting internal surfaces, which can perturb the machine protection systems based on infrared (IR) thermography. To ameliorate this situation, we have measured and modelled in the 3-5 μm wavelength range the bi-directional reflection distribution function (BRDF) of wall material samples from Tore Supra and conducted in situ reflection measurements and simulated them with the CEA COSMOS code. BRDF results are presented for B 4 C and carbon fibre composite (CFC) tiles. The hemispherical integrated reflection ranges from 0.12 for the B 4 C sample to 0.39 for a CFC tile from the limiter erosion zone. In situ measurements of the IR reflection of a blackbody source off an ICRH and an LHCD antenna of Tore Supra are well reproduced by the simulation.

  10. Infrared reflection properties and modelling of in situ reflection measurements on plasma-facing materials in Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Reichle, R; Desgranges, C; Faisse, F; Pocheau, C [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Lasserre, J-P; Oelhoffen, F; Eupherte, L; Todeschini, M [CEA, DAM, CESTA, F-33114 Le Barp (France)

    2009-12-15

    Tore Supra has-like ITER-reflecting internal surfaces, which can perturb the machine protection systems based on infrared (IR) thermography. To ameliorate this situation, we have measured and modelled in the 3-5 {mu}m wavelength range the bi-directional reflection distribution function (BRDF) of wall material samples from Tore Supra and conducted in situ reflection measurements and simulated them with the CEA COSMOS code. BRDF results are presented for B{sub 4}C and carbon fibre composite (CFC) tiles. The hemispherical integrated reflection ranges from 0.12 for the B{sub 4}C sample to 0.39 for a CFC tile from the limiter erosion zone. In situ measurements of the IR reflection of a blackbody source off an ICRH and an LHCD antenna of Tore Supra are well reproduced by the simulation.

  11. Towards long pulse high performance discharges in Tore Supra: experimental knowledge and technological developments for heat exhaust

    International Nuclear Information System (INIS)

    1995-08-01

    This document deals with fusion heat exhaust experiments in Tore Supra tokamak. The purpose of the Tore Supra tokamak is to achieve and control long pulse powerful discharges. High input power is required to generate the non inductive current, approximately 25 MW . The conception and realisation of a Plasma Facing Component (PFC) scheme able to deal with this large amount of power is the main issue. A description of the water loop used for power removal and of the calorimetric system to determine the overall heat exhaust balance is provided. The infra-red measurements used during plasma operation are also described, together with several heat exhaust devices. The behaviour of ion cyclotron and lower hybrid wave launchers is addressed. Eventually, some information is provided on technological developments of PFC in Tore Supra. (TEC). 61 refs., 34 figs

  12. Cybele: a large size ion source of module construction for Tore-Supra injector

    International Nuclear Information System (INIS)

    Simonin, A.; Garibaldi, P.

    2005-01-01

    A 70 keV 40 A hydrogen beam injector has been developed at Cadarache for plasma diagnostic purpose (MSE diagnostic and Charge exchange) on the Tore-Supra Tokamak. This injector daily operates with a large size ions source (called Pagoda) which does not completely fulfill all the requirements necessary for the present experiment. As a consequence, the development of a new ion source (called Cybele) has been underway whose objective is to meet high proton rate (>80%), current density of 160 mA/cm 2 within 5% of uniformity on the whole extraction surface for long shot operation (from 1 to 100 s). Moreover, the main particularity of Cybele is the module construction concept: it is composed of five source modules vertically juxtaposed, with a special orientation which fits the curved extraction surface of the injector; this curvature ensures a geometrical focalization of the neutral beam 7 m downstream in the Tore-Supra chamber. Cybele will be tested first in positive ion production for the Tore-Supra injector, and afterward in negative ion production mode; its modular concept could be advantageous to ensure plasma uniformity on the large extraction surface (about 1 m 2 ) of the ITER neutral beam injector. A module prototype (called the Drift Source) has already been developed in the past and optimized in the laboratory both for positive and negative ion production, where it has met the ITER ion source requirements in terms of D-current density (200 A/m 2 ), source pressure (0.3 Pa), uniformity and arc efficiency (0.015 A D-/kW). (authors)

  13. Tore-Supra infrared thermography system, a real steady-state diagnostic

    International Nuclear Information System (INIS)

    Guilhem, D.; Bondil, J.L.; Bertrand, B.; Desgranges, C.; Lipa, M.; Messina, P.; Missirlian, M.; Portafaix, C.; Reichle, R.; Roche, H.; Saille, A.

    2005-01-01

    Tore-Supra Tokamak (I p = 1.5 MA, B t = 4 T) has been constructed with a steady-state magnetic field using super-conducting magnets and water-cooled plasma facing components (PFCs) for high-performance long pulse plasma discharges. When not actively cooled, plasma facing components can only accumulate a limited amount of energy since the temperature increases continuously during the discharge until radiation cooling equals the incoming heat flux. Such an environment is found in the JET Tokamak [JET Team, IAEA-CN-60/A1-3, Seville, 1994] and on TRIAM [M. Sakamoto, H. Nakashima, S. Kawasaki, A. Iyomasa, S.V. Kulkarni, M. Hasegawa, E. Jotaki, H. Zushi, K. Nakamura, K. Hanada, S. Itoh, Static and dynamic properties of wall recycling in TRIAM-1M, J. Nucl. Mater. 313-316 (2003) 519-523] [Y. Kamada, et al., Nucl. Fusion 3 (1999) 1845]. In Tore-Supra, the surface temperature of the actively cooled plasma facing components reach steady state within a second. We present here the Tore-Supra thermographic system, made of seven endoscope bodies equipped so far with eight infrared (IR) cameras. It has to be noted that this diagnostic is the first diagnostic to be actively cooled, as required for steady state. The main purpose of such a diagnostic is to prevent the plasma to damage the actively cooled plasma facing components (ACPFCs), which consist of the toroidal pumped limiter (TPL), 7 m 2 , and of five radio-frequency antennae, 1.5 m 2 each

  14. Operation of an ITER relevant inspection robot on Tore Supra tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Gargiulo, Laurent [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)], E-mail: laurent.gargiulo@cea.fr; Bayetti, Pascal; Bruno, Vincent; Hatchressian, Jean-Claude; Hernandez, Caroline; Houry, Michael [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Keller, Delphine [CEA, LIST, Service de Robotique Interactive, F-92265 Fontenay aux Roses (France); Martins, Jean-Pierre [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Measson, Yvan; Perrot, Yann [CEA, LIST, Service de Robotique Interactive, F-92265 Fontenay aux Roses (France); Samaille, Frank [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)

    2009-06-15

    Robotic operations are one of the major maintenance challenges for ITER and future fusion reactors. CEA has developed a multipurpose carrier able to realize deployments in the plasma vessel without breaking the Ultra High Vacuum (UHV) and temperature conditioning. A 6 years R and D programme was jointly conducted by CEA-LIST Interactive Robotics Unit and the Institute for Magnetic Fusion Research (IRFM) in order to demonstrate the feasibility and reliability of an in-vessel inspection robot relevant to ITER requirements. The Articulated Inspection Arm robot (AIA) is an 8-m long multilink carrier with a payload up to 10 kg operable between plasma under tokamak conditioning environment; its geometry allows a complete close inspection of Plasma Facing Components (PFCs) of the Tore Supra vessel. Different tools are being developed by CEA to be plugged at the front head of the carrier. The diagnostic presently in operation consists in a viewing system offering accurate visual inspection of PFCs. Leak detection of first wall based on helium sniffing and laser compact system for carbon co-deposited layers characterizations or treatments are also considered for demonstration. In April 2008, the AIA robot equipped with its vision diagnostic has realized a complete deployment into Tore Supra and the first closed inspection of the vessel under UHV conditions. During the upcoming experimental campaign, the same operation will be performed under relevant conditions (10{sup -6} Pa and 120 deg. C) after a conditioning phase at 200 deg. C to avoid outgassing pollution of the chamber. This paper describes the different steps of the project development, robot capabilities with the present operations conducted on Tore Supra and future requirements for making the robot a tool for tokamak routine operation.

  15. Ion temperature measurements in the scrape-off layer of the Tore Supra Tokamak

    International Nuclear Information System (INIS)

    Kocan, M.

    2009-10-01

    The thesis describes measurements of the scrape-off layer (SOL) ion temperature T i with a retarding field analyzer (RFA) in the limiter tokamak Tore Supra. Considerable emphasis is placed on study of the instrumental effects of RFAs and their influence on T i measurements. In general, the influence of instrumental effects on T i measurements is found to be relatively small. The instrumental study is followed by systematic measurements of T i (as well as other parameters) in the Tore Supra SOL. This includes the scaling of SOL temperatures and electron density with the main plasma parameters (such as the plasma density, toroidal magnetic field, working gas, and the radiated power fraction). Except at very high densities or in detached plasmas, SOL T i is found to be higher than T e by up to a factor of 7. While SOL T i is found to vary by almost two orders of magnitude, following the variation of the core temperatures, SOL T e changes only little and seems to be decoupled from the core plasma. The first continuous T i /T e profile from the edge of the confined plasma into the SOL is constructed using data from different tokamaks. It is shown that T i /T e > 1 in the SOL but also in the confined plasma, and increases with radius. The first evidence of poloidal asymmetry of the radial ion and electron energy transport in the SOL is reported. Implications for ITER start-up phase are discussed. Correlation of the asymmetries of SOL T i and T e measured from both directions along the magnetic field lines with changes of the parallel Mach number is studied. SOL T i was measured for the first time in Tore Supra by charge exchange recombination spectroscopy (CXRS) and compared to RFA data. A factor of 4 higher T i measured by CXRS is a subject of further analysis. (A.C.)

  16. Observation of the m = 1 mode by microwave transmission measurements in the Tore Supra tokamak

    International Nuclear Information System (INIS)

    Giruzzi, G.; Segui, J.L.; Pecquet, A.L.; Gil, C.

    1991-06-01

    Microwave transmission measurements in the Tore Supra tokamak exhibit low-frequency oscillations of the transmitted power, associated to the presence of a saturated m = 1, n = 1 mode, as observed by soft X-ray diagnostics. It is shown that these oscillations are related to refraction effects, and specifically to modulations of the electron density profile due to a rotating magnetic island. An analytical solution of the ray equations in the presence of a rotating density perturbation is found, explaining the frequency spectrum of the oscillations

  17. Depletion of hydrogenoid atoms from the carbonized layer in Tore Supra

    International Nuclear Information System (INIS)

    Crisolia, C.; Grosman, A.; Bardon, J.

    1992-01-01

    The wall production of deuterium and hydrogen during an helium glow discharge of 1.6x10 5 s has been studied after 100 deuterium plasma shots in Tore Supra. After a transient, the desorption followed a t -1 time behaviour for the deuterium a t -1/2 behaviour for the hydrogen. The results are discussed in terms of ion-induced release for the deuterium and a diffusion-limited mechanism for the hydrogen. The values obtained for the different parameters are in good agreement with the relevant data of the literature. (orig.)

  18. Power deposition profile during lower hybrid current drive in Tore Supra

    International Nuclear Information System (INIS)

    Pecquet, A.L.; Moreau, D.; Fall, T.; Lasalle, J.; Lecoustey, P.; Mattioli, M.; Peysson, Y.; Auge, N.; Rodriguez, L.; Talvard, M.; Hubbard, A.; Moret, J.M.

    1991-01-01

    Lower hybrid current drive (LHCD) experiments have been performed in Tore Supra in various density regimes. The total power coupled to the plasma reached 4MW and a strong electron heating has been observed. To investigate the power deposition mechanism on the electrons, r.f power modulation experiments have been performed. These experiments allow us to estimate the power deposition profiles on both thermal and non-thermal electrons and also to study their respective time responses. From these studies it is possible to deduce a thermal heating scenario which agrees with the experimental results

  19. Quench and safety tests on a toroidal field coil of Tore Supra

    International Nuclear Information System (INIS)

    Ciazynski, D.; Cure, C.; Duchateau, J.L.

    1987-01-01

    As a part of the safety analysis of the magnet, three quenches have been initiated in one of the TF coils in the Saclay test facility. While transporting a given current, the coil is insulated from the refrigerator: the temperatures of the helium and of the coil increase slowly on account of thermal losses. At the current sharing temperature a quench rapidly propagates and the protection system makes the coil discharge in the dump resistor. At three levels of current, electrical, thermal and hydraulic measurements have been performed. All these results are taken into account for the safety design of TORE SUPRA

  20. Particle pinch with fully noninductive lower hybrid current drive in Tore Supra.

    Science.gov (United States)

    Hoang, G T; Bourdelle, C; Pégourié, B; Schunke, B; Artaud, J F; Bucalossi, J; Clairet, F; Fenzi-Bonizec, C; Garbet, X; Gil, C; Guirlet, R; Imbeaux, F; Lasalle, J; Loarer, T; Lowry, C; Travère, J M; Tsitrone, E

    2003-04-18

    Recently, plasmas exceeding 4 min have been obtained with lower hybrid current drive (LHCD) in Tore Supra. These LHCD plasmas extend for over 80 times the resistive current diffusion time with zero loop voltage. Under such unique conditions the neoclassical particle pinch driven by the toroidal electric field vanishes. Nevertheless, the density profile remains peaked for more than 4 min. For the first time, the existence of an inward particle pinch in steady-state plasma without toroidal electric field, much larger than the value predicted by the collisional neoclassical theory, is experimentally demonstrated.

  1. In service experience feed back of the tore supra actively cooled inner first wall

    International Nuclear Information System (INIS)

    Schlosser, J.; Chappuis, P.; Chatelier, M.; Cordier, J.J.; Deschamps, P.; Garampon, L.; Guilhem, D.; Lipa, M.; Mitteau, R.

    1994-01-01

    Over 12000 plasma shots (some of them up to 8 MW of additional power and same as long as 60 s) have been achieved in TORE SUPRA (TS) with a significant number of them limited by thr inner first wall. This actively water cooled wall is covered with brazed graphite tiles. High power - high energy experiments have shown that a reliability of the graphite tile/heat sink joint and an accurate alignment of the wall are needed. This paper summarizes the experience gained with this component and developments in progress in order to improve the performance of such a inner first wall. (authors). 9 refs., 13 figs., 2 tabs

  2. In service experience feed back of the tore supra actively cooled inner first wall

    Energy Technology Data Exchange (ETDEWEB)

    Schlosser, J; Chappuis, P; Chatelier, M; Cordier, J J; Deschamps, P; Garampon, L; Guilhem, D; Lipa, M; Mitteau, R

    1994-12-31

    Over 12000 plasma shots (some of them up to 8 MW of additional power and same as long as 60 s) have been achieved in TORE SUPRA (TS) with a significant number of them limited by thr inner first wall. This actively water cooled wall is covered with brazed graphite tiles. High power - high energy experiments have shown that a reliability of the graphite tile/heat sink joint and an accurate alignment of the wall are needed. This paper summarizes the experience gained with this component and developments in progress in order to improve the performance of such a inner first wall. (authors). 9 refs., 13 figs., 2 tabs.

  3. Electron cyclotron resonance heating assisted plasma startup in the Tore Supra tokamak

    International Nuclear Information System (INIS)

    Bucalossi, J.; Hertout, P.; Lennholm, M.; Saint-Laurent, F.; Bouquey, F.; Darbos, C.; Traisnel, E.

    2009-04-01

    ECRH assisted plasma startup at fundamental resonance is investigated in Tore Supra in view of ITER operation. ECRH pre-ionisation is found to be very efficient allowing plasma initiation in a wide range of pre-fill pressure compared to ohmic startup. Reliable assisted startup has been achieved at the ITER reference toroidal electric field (0.3 V/m) with 160 kW of ECRH. Resonance location scan indicates that the plasma is initiated at the resonance location and that the plasma current channel position had to be real-time controlled since the very beginning of the discharge to obtain robust plasma startup. (authors)

  4. Synergy between electron cyclotron and lower hybrid current drive on Tore Supra

    International Nuclear Information System (INIS)

    Giruzzi, G.; Artaud, J.F.; Dumont, R.J.; Imbeaux, F.; Bibet, P.; Berger-By, G.; Bouquey, F.; Clary, J.; Darbos, C.; Ekedahl, A.; Hoang, G.T.; Lennholm, M.; Maget, P.; Magne, R.; Segui, J.L.; Bruschi, A.; Granucci, G.

    2005-01-01

    Improvement (up to a factor ∼ 4) of the electron cyclotron (EC) current drive efficiency in plasmas sustained by lower hybrid (LH) current drive has been demonstrated in stationary conditions on the Tore Supra tokamak. This was made possible by feedback controlled discharges at zero loop voltage, constant plasma current and density. This effect, predicted by kinetic theory, results from a favorable interplay of the velocity space diffusions induced by the two waves: the EC wave pulling low-energy electrons out of the Maxwellian bulk, and the LH wave driving them to high parallel velocities. (author)

  5. An H minority heating regime in Tore Supra showing improved L mode confinement

    International Nuclear Information System (INIS)

    Hoang, G.T.; Monier-Garbet, P.; Aniel, T.

    2000-01-01

    Tore Supra experiments are at present devoted to the study of high density regimes with radiofrequency heating. Recently, an improved L mode confinement regime has been observed in plasmas heated by ion cyclotron hydrogen minority heating, at relatively high densities up to 80% of the Greenwald limit. The quality of energy confinement is as good as that of ELMy H mode. The main physical mechanism of this regime has not been clearly identified. However, some features very similar to those of previous improved confinement modes using neutral beam heating in other tokamaks have been observed. (author)

  6. Near infrared thermography by CCD cameras and application to first wall components of Tore Supra tokamak

    International Nuclear Information System (INIS)

    Moreau, F.

    1996-01-01

    In the Tokamak TORE-SUPRA, the plasma facing components absorbs and evacuate (active cooling) high power fluxes (up to 10 MW/m 2 ). Their thermal behavior study is essential for the success of controlled thermonuclear fusion line. The first part is devoted to the study of power deposition on the TORE-SUPRA actively cooled limiters. A model of power deposition on one of the limiters is developed. It Takes into account the magnetic topology and a description of the plasma edge. The model is validated with experimental calorimetric data obtained during a series of shots. This will allow to compare the surface temperature measurements with the predicted ones. The main purpose of this thesis was to evaluate and develop a new surface temperature measurement system. It works in the near infrared range (890 nm) and is designed to complete the existing thermographic diagnostic of TORE-SUPRA. By using the radiation laws (for a blackbody and the plasma) ant the laboratory calibration one can estimate the surface temperature of the observed object. We evaluate the performances and limits of such a device in the harsh conditions encountered in a Tokamak environment. On the one hand, in a quasi ideal situation, this analysis shows that the range of measurement is 600 deg. C to 2500 deg. C. On the other hand, when one takes into account of the plasma radiation (with an averaged central plasma density of 6.10 19 m -3 ), we find that the minimum surface temperature rise to 900 deg. C. In the near future, according to the development of IR-CCD cameras working in the near infrared range up to 2 micrometers, we will be able to keep the good spatial resolution with an improved lower limit for the temperature down to 150 deg. C. The last section deals with a number of computer tools to process the images obtained from experiments on TORE-SUPRA. A pattern recognition application was especially developed to detect a complex plasma iso-intensity structure. (author)

  7. Near infrared thermography by CCD cameras and application to first wall components of Tore Supra tokamak

    International Nuclear Information System (INIS)

    Moreau, F.

    1996-01-01

    In the Tokamak TORE-SUPRA, the plasma facing components absorbs and evacuate (active cooling) high power fluxes (up to 10 MW/m 2 ). Their thermal behavior study is essential for the success of controlled thermonuclear fusion line. The first part is devoted to the study of power deposition on the TORE-SUPRA actively cooled limiters. A model of power deposition on one of the limiters is developed. It takes into account the magnetic topology and a description of the plasma edge. The model is validated with experimental calorimetric data obtained during a series of shots. This will allow to compare the surface temperature measurements with the predicted ones. The main purpose of this thesis was to evaluate and develop a new temperature measurement system. It works in the near infrared range (890 nm) and is designed to complete the existing thermographic diagnostic of TORE-SUPRA. By using the radiation laws (for a blackbody and the plasma) and the laboratory calibration one can estimate the surface temperature of the observed object. We evaluate the performances and limits of such a device in the harsh conditions encountered in a Tokamak environment. On the one hand, in a quasi ideal situation, this analysis shows that the range of measurements is 600 deg. C to 2500 deg. C. On the other hand, when one takes into account of the plasma radiation (with an averaged central plasma density of 6.10 19 m -3 ), we find that the minimum surface temperature rise to 900 deg. C instead of 700 deg. C. In the near future, according to the development of IR-CCD cameras working in the near infrared range up to 2 micrometers, we will be able to keep the good spatial resolution with an improved lower limit for the temperature down to 150 deg. C. The last section deals with a number of computer tools to process the images obtained from experiments on TORE-SUPRA. A pattern recognition application was especially developed to detect a complex plasma iso-intensity structure. (author)

  8. Mechanical stress analysis for the poloidal field coils of TORE SUPRA

    International Nuclear Information System (INIS)

    Ane, J.M.; Perin, J.P.

    1985-01-01

    Hoop stresses, up to 100 MPa, in the poloidal field coils of TORE SUPRA have to be reacted back to the main body of the coil where a conductor ends or is twisted for an interturn or an interlayer transition. The load is taken by shear stress through the insulation. Carefully designed configurations, based on 1D, 2D and 3D analysis results, limit the shear stress levels to 15 MPa. A fatigue test of a conductor termination has shown that the experimental results are in good agreement with the calculated stresses

  9. Experiments on FW-IBW mode conversion heating combined with LHCD on Tore Supra

    International Nuclear Information System (INIS)

    Basiuk, V.; Becoulet, A.; Imbeaux, F.; Nguyen, F.; Peysson, Y.; Monakhov, I.; Petrov, Y.; Petrov, Y.

    1999-01-01

    Recent RF heating and current drive investigations revealed a growing interest in a scheme based on mode conversion (MC) of externally excited fast waves (FW) to ion Bernstein waves (IBW). Suitability of MC scheme for on/off axis electron heating has already been reported on Tore Supra. New results, which were obtained during MC experiments combined with Low Hybrid Current Drive (LHCD) are presented in this paper. Application of new experimental tools and numerical techniques provided better insight into the problem of MC power deposition. an outcome of active search for synergistic LHCD-IBW current drive effects is also reported

  10. Theoretical and experimental study of the hybrid wave coupling in Tore Supra and Jet by multijunction antennas

    International Nuclear Information System (INIS)

    Litaudon, X.

    1990-06-01

    The hybrid or slow electron plasma waves propagation and coupling are investigated in a toroidal magnetic confinement configuration such as found in Tokamaks. The main characteristics of the antenna, formed of several waveguides displaced in the toroidal direction, are studied. The equations of the hybrid waves linear propagation are solved for a plane geometrical configuration and in an inhomogeneous plasma. The optimization of the hybrid wave couplers of Tore Supra and Jet is carried out by means of the SWAN code. The results of the experiments performed on Tore Supra are analyzed. The investigation shows that the wave coupling depends on the edge plasma properties [fr

  11. A new protection system against high voltage vacuum breakdowns developed for the Tore Supra neutral beam injector prototype

    International Nuclear Information System (INIS)

    Fumelli, M.; Jequier, F.; Pamela, J.

    1988-01-01

    A passive protection system against high voltage vacuum breakdowns has been developed. This system is based on the principle of oscillatory discharges in an RLC circuit coupled with the use of a diode. It allows the interruption of a vacuum breakdown in a few milliseconds. This study has been made for protecting some parts of the neutral beam injectors of the Tore Supra Tokamak experiment, but its field of application should be quite large. The conception of the whole high voltage electrical circuit developed for the Tore Supra injector prototype experiments is also presented

  12. Note: Measurements of fast electrons in the TORE-SUPRA tokamak by means of modified Cherenkov-type diamond detector

    Energy Technology Data Exchange (ETDEWEB)

    Jakubowski, L.; Sadowski, M. J.; Zebrowski, J.; Rabinski, M.; Jakubowski, M. J.; Malinowski, K.; Mirowski, R. [National Centre for Nuclear Research (NCBJ), 7 Andrzeja Soltana Str., 05-400 Otwock (Poland); Lotte, Ph.; Goniche, M.; Gunn, J.; Colledani, G.; Pascal, J.-Y.; Basiuk, V. [CEA, IRFM, F-13108 Saint Paul-lez-Durance (France)

    2013-01-15

    The Note reports on experimental studies of ripple born fast electrons within the TORE-SUPRA facility, which were performed by means of a modified measuring head equipped with diamond detectors designed especially for recording the electron-induced Cherenkov radiation. There are presented signals produced by fast electrons in the TORE-SUPRA machine, which were recorded during two experimental campaigns performed in 2010. Shapes of these electron-induced signals are considerably different from those observed during the first measurements carried out by the prototype Cherenkov probe in 2008. An explanation of the observed differences is given.

  13. Note: Measurements of fast electrons in the TORE-SUPRA tokamak by means of modified Cherenkov-type diamond detector

    International Nuclear Information System (INIS)

    Jakubowski, L.; Sadowski, M. J.; Zebrowski, J.; Rabinski, M.; Jakubowski, M. J.; Malinowski, K.; Mirowski, R.; Lotte, Ph.; Goniche, M.; Gunn, J.; Colledani, G.; Pascal, J.-Y.; Basiuk, V.

    2013-01-01

    The Note reports on experimental studies of ripple born fast electrons within the TORE-SUPRA facility, which were performed by means of a modified measuring head equipped with diamond detectors designed especially for recording the electron-induced Cherenkov radiation. There are presented signals produced by fast electrons in the TORE-SUPRA machine, which were recorded during two experimental campaigns performed in 2010. Shapes of these electron-induced signals are considerably different from those observed during the first measurements carried out by the prototype Cherenkov probe in 2008. An explanation of the observed differences is given.

  14. Edge density profile measurements by X-mode reflectometry on Tore Supra

    International Nuclear Information System (INIS)

    Clairet, F.; Bottereau, C.; Chareau, J.M.; Paume, M.; Sabot, R.

    2000-10-01

    A broadband reflectometer operating in the frequency range 50-75 GHz has been developed on Tore Supra to measure electron density profiles at the edge. The system uses extraordinary mode polarization and performs routine measurements in 20 μs with a heterodyne detection to ensure a high dynamic range sensitivity. It allows separate phase and amplitude information of the signal. The density profiles are fully automatically calculated from the raw phase. The initialization is done with an automatic detection of the first cut-off from the amplitude of the reflected signal with accuracy up to ±0.5 cm. The profiles are now part of the public database of Tore Supra (TS) and can provide details of density structures better than the centimeter range. High reliability of the measurements for various plasma conditions make this diagnostic an ideal tool to study specific edge plasma physics with given examples on detached plasma behaviour and RF antenna-plasma coupling processes. It also is shown how the presence of suprathermal electrons may perturb the measurements. (authors)

  15. Profile measurements of localized fast electrons and ions in TORE SUPRA

    International Nuclear Information System (INIS)

    Basiuk, V.; Roubin, J.P.; Becoulet, A.; Carrasco, J.; Martin, G.; Moreau, D.; Saoutic, B.

    1992-01-01

    The strong toroidal and poloidal anisotropy of the heat flux to the first wall of Tore Supra during additional heating has been related to suprathermal particle losses induced by the TF ripple. In this paper we describe a new system of electric collectors designed to diagnose these localized particles and we analyse measurements performed during LHCD, ICRH and NBI heating. The interaction of fast particles created by additional heating with the TF ripple perturbation in Tore Supra has been analyzed by a direct measurement of the localized particles. The good confinement region has been identified thanks to a peak in the measured current profiles and is in agreement with theory. During LHCD and ICRH, the global losses are weak but strongly anisotropic leading to hot spots at the wall. During ICRH, an ejection of fast ions by the sawteeth towards peripheral zones where they get lost in the ripple has been seen. This is a possible scenario of α particle losses in a reactor

  16. Thermal electron transport in regimes with low and negative magnetic shear in Tore Supra

    International Nuclear Information System (INIS)

    Voitsekhovitch, I.; Litaudon, X.; Moreau, D.; Aniel, T.; Becoulet, A.; Erba, M.; Joffrin, E.; Kazarian-Vibert, F.; Peysson, Y.

    1997-01-01

    The magnetic shear effect on thermal electron transport is studied in a large variety of non-inductive plasmas in Tore Supra. An improved confinement in the region of low and negative shear was observed and quantified with an exponential dependence on the magnetic shear (Litaudon, et al., Fusion Energy 1996 (Proc. 16th Int. Conf. Montreal, 1996), Vol. 1, IAEA, Vienna (1997) 669). This is interpreted as a consequence of a decoupling of the global modes (Romanelli and Zonca, Phys. Fluids B 5 (1993) 4081) that are thought to be responsible for anomalous transport. This dependence is proposed in order to complete the Bohm-like L mode local electron thermal diffusivity so as to describe the transition from Bohm-like to gyroBohm transport in the plasma core. The good agreement between the predictive simulations of the different Tore Supra regimes (hot core lower hybrid enhanced performance, reversed shear plasmas and combined lower hybrid current drive and fast wave electron heating) and experimental data provides a basis for extrapolation of this magnetic shear dependence in the local transport coefficients to future machines. As an example, a scenario for non-inductive current profile optimization and control in ITER is presented. (author)

  17. Real time determination and control of the plasma localisation and internal inductance in Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Saint-Laurent, F. E-mail: stlauren@drfc.cad.cea.fr; Martin, G

    2001-10-01

    The study of long-duration high-power discharges need an efficient real time control of the plasma parameters, especially the plasma position when RF heating systems are used. On Tore Supra, recent improvements have been carried out (i) for the poloidal interpolation and the radial extrapolation of the magnetic measurements, (ii) for a better feedback matrix converting the radial errors of the plasma position to voltage values for the poloidal generators, and (iii) for a very fast solution to find the plasma parameters from the knowledge of its surface. The plasma edge localisation is now controlled with a precision better than 1 cm and controlled within a few millimetres uncertainty for several tenths of seconds. Moreover, for advanced tokamak scenarios, a precise real time determination of safety factor, poloidal beta, internal inductance, Shafranov shift as well as the online computation of the electron density and current density profiles are now available on Tore Supra. These quantities compare well with results from batch calculations using an equilibrium code. To fulfil the new requirements of plasma control for the CIEL project, a local control of the plasma edge position and curvature is planned for the near future.

  18. Experimental demonstration of synergy between electron cyclotron and lower hybrid current drive on Tore Supra

    International Nuclear Information System (INIS)

    Artaud, J.F.; Giruzzi, G.; Dumont, R.J.; Imbeaux, F.; Bibet, P.; Bouquey, F.; Clary, J.; Ekedahl, A.; Hoang, G.T.; Lennholm, M.; Magne, R.; Segui, J.L.

    2004-01-01

    Non-inductive current drive (CD) has two main applications in tokamaks: sustainment of a substantial fraction of the toroidal plasma current necessary for the plasma confinement and control of the plasma stability and transport properties by appropriate shaping of the current density profile. For the first kind of applications, lower hybrid (LH) waves are known to provide the highest efficiency (defined as the ratio of the driven current to the injected wave power), although with limited control capability. Conversely, electron cyclotron (EC) waves drive highly localized currents, and are therefore particularly suited for control purposes, but their CD efficiency is much lower than that of LH waves (typically, an order of magnitude in present day experiments). Various calculations have demonstrated an interesting property: the current driven by the simultaneous use of the two waves, I(LH+EC), can be significantly larger than the sum I(LH)+I(EC) of the currents separately driven by the two waves in the same plasma conditions. This property, called synergy effect. The peculiar experimental conditions attainable on the Tore Supra tokamak have allowed the first experimental demonstration of the synergy between EC and LH current drive. The significant improvement of the electron cyclotron current drive (ECCD) efficiency in the presence of low hybrid current drive (LHCD), predicted by kinetic theory and confirmed by stationary experiments on Tore Supra, opens up the possibility of using ECCD as an efficient current profile control tool in LHCD plasmas

  19. Study of plasma turbulence by ultrafast sweeping reflectometry on the Tore Supra Tokamak

    International Nuclear Information System (INIS)

    Hornung, Gregoire

    2013-01-01

    The performance of a fusion reactor is closely related to the turbulence present in the plasma. The latter is responsible for anomalous transport of heat and particles that degrades the confinement. The measure and characterization of turbulence in tokamak plasma is therefore essential to the understanding and control of this phenomenon. Among the available diagnostics, the sweeping reflectometer installed on Tore Supra allows to access the plasma density fluctuations from the edge to the centre of the plasma discharge with a fine spatial (mm) and temporal resolution (μs), that is of the order of the characteristic turbulence scales.This thesis consisted in the characterization of plasma turbulence in Tore Supra by ultrafast sweeping reflectometry measurements. Correlation analyses are used to quantify the spatial and temporal scales of turbulence as well as their radial velocity. In the first part, the characterization of turbulence properties from the reconstructed plasma density profiles is discussed, in particular through a comparative study with Langmuir probe data. Then, a parametric study is presented, highlighting the effect of collisionality on turbulence, an interpretation of which is proposed in terms of the stabilization of trapped electron turbulence in the confined plasma. Finally, it is shown how additional heating at ion cyclotron frequency produces a significant though local modification of the turbulence in the plasma near the walls, resulting in a strong increase of the structure velocity and a decrease of the correlation time. The supposed effect of rectified potentials generated by the antenna is investigated via numerical simulations. (author) [fr

  20. Predictive simulations of radio frequency heated plasmas of Tore Supra using the Multi-Mode model

    International Nuclear Information System (INIS)

    Voitsekhovitch, Irina; Bateman, Glenn; Kritz, Arnold H.; Pankin, Alexei

    2002-01-01

    Multichannel integrated predictive simulations using the Multi-Mode transport model are carried out for radio frequency heated Tore Supra tokamak discharges in which helium is the primary ion component. Lower hybrid heated discharges in which the total current is driven noninductively [X. Litaudon et al., Plasma Phys. Controlled Fusion 43, 677 (2001)] and a discharge with ion cyclotron radio frequency heating of the hydrogen minority ions [G. T. Hoang et al., Nucl. Fusion 38, 117 (1998)] are simulated. The simulations of these discharges represent the first test of the Multi-Mode model in helium plasmas with dominant electron heating. Also for the first time, the particle transport in Tore Supra discharges is computed and the density profiles are predicted self-consistently with other transport channels. It is found in these simulations that the anomalous transport driven by trapped electron mode turbulence is dominant compared to the transport driven by the ion temperature gradient turbulence. The feature of the Multi-Mode model to calculate the impurity transport self-consistently with other transport channels is used in this study to predict the influence of carbon impurity influx on the discharge evolution

  1. Coupling properties and edge plasma interaction characteristics of the new Tore Supra lower hybrid antenna

    International Nuclear Information System (INIS)

    Bibet, Ph.; Fuchs, V.; Mailloux, J.

    1999-01-01

    A significant part of the non-inductive in Tore Supra will be driven by a new launcher, to be installed in September 1999. The antenna phase 2 is made of 6 rows with 48 active waveguides and 9 passive ones in each. Passive waveguides are inserted at every 6. active one. This grill has been designed in the frame of the CIEL project. It will inject 4 MW at 3.7 GHz at a safe power density of 25 MW/m 2 for a pulse length of 1000 s. The radiated spectrum peaks at N // = 2.03 with a possible variation of ± 0.35 and a FWHM of 0.35. In order to prepare for operation with this grill, the coupling properties and the power directivity of the radiated spectra have been studied as a function of: the electron density and electron density gradient ; the feeding phase shift between the 8 antenna modules; the geometry of the antenna. Furthermore, the interaction of plasma edge electrons with the antenna is analysed and a comparison with the previous Tore Supra antenna is made. This is done for a range of plasma parameters and feeding phase. (authors)

  2. Pioneering superconducting magnets in large tokamaks: evaluation after 16 years of operating experience in tore supra

    International Nuclear Information System (INIS)

    Duchateau, J.L.; Gravil, B.; Tena, E.; Henry, D.; Journeaux, J.Y.; Libeyre, P.

    2004-01-01

    The toroidal field (TF) system of Tore Supra (TS) is superconducting. After 16 years of operation it is possible to give an overview of the experience gained on a large superconducting system integrated in a large Tokamak. Quantitative data will be given, about the TF system for the cryogenic system and for the magnet system as well, concerning the number of plasmas shots and the availability of the machine. The origin and the number of breakdowns or incidents will be described, with emphasis on cryogenics, to document repairs and changes on the system components. Concerning the behaviour during operation, the Fast Safety Discharges (FSD) in operation are of particular interest for the Tokamak operation, as they interrupt it on a significant time of the order of one hour. This aspect is particularly documented. The approach followed to decrease the number of these FSD will be reported and explained. The Tore Supra Tokamak was the first important meeting between Superconductivity and Plasma Physics on a large scale. Overall, despite the differences in design and size, the accumulated experience over 16 years of operation is a useful tool to prepare the manufacturing and the operation of the ITER magnets. (authors)

  3. High heat flux actively cooled plasma facing components development, realization and first results in Tore Supra

    International Nuclear Information System (INIS)

    Grosman, A.

    2004-01-01

    The development, design, manufacture and testing of actively cooled high heat flux plasma facing components (PFC) has been an essential stage towards long powerful tokamak operations for Tore-Supra, it lasted about 10 years. This paper deals with the toroidal pumped limiter (TPL) that is able to sustain up to 10 MW/m 2 of nominal heat flux. This device is based on hardened copper alloy heat sink structures covered by a carbon fiber composite armour, it resulted in the manufacturing of 600 elementary components, called finger elements, to achieve the 7.6 m 2 TPL. This assembly has been operating in Tore-Supra since spring 2002. Some difficulties occurred during the manufacturing phase, the valuable industrial experience is summarized in the section 2. The permanent monitoring of PFC surface temperature all along the discharge is performed by a set of 6 actively cooled infrared endoscopes. The heat flux monitoring and control issue but also the progress made in our understanding of the deuterium retention in long discharges are described in the section 3. (A.C.)

  4. High heat flux actively cooled plasma facing components development, realization and first results in Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Grosman, A. [Association Euratom-CEA, Centre d' Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee

    2004-07-01

    The development, design, manufacture and testing of actively cooled high heat flux plasma facing components (PFC) has been an essential stage towards long powerful tokamak operations for Tore-Supra, it lasted about 10 years. This paper deals with the toroidal pumped limiter (TPL) that is able to sustain up to 10 MW/m{sup 2} of nominal heat flux. This device is based on hardened copper alloy heat sink structures covered by a carbon fiber composite armour, it resulted in the manufacturing of 600 elementary components, called finger elements, to achieve the 7.6 m{sup 2} TPL. This assembly has been operating in Tore-Supra since spring 2002. Some difficulties occurred during the manufacturing phase, the valuable industrial experience is summarized in the section 2. The permanent monitoring of PFC surface temperature all along the discharge is performed by a set of 6 actively cooled infrared endoscopes. The heat flux monitoring and control issue but also the progress made in our understanding of the deuterium retention in long discharges are described in the section 3. (A.C.)

  5. Pioneering superconducting magnets in large tokamaks: Evaluation after 16 years of operating experience in tore supra

    International Nuclear Information System (INIS)

    Libeyre, P.; Duchateau, J.L.; Gravil, B.; Tena, E.; Henry, D.; Journeaux, J.Y.

    2005-01-01

    The toroidal field (TF) system of TORE SUPRA (TS) is superconducting. After 16 years of operation it is possible to give an overview of the experience gained on a large superconducting system integrated in a large Tokamak. Quantitative data will be given, about the TF system for the cryogenic system and for the magnet system as well, concerning the number of plasmas shots and the availability of the machine. The origin and the number of breakdowns or incidents will be described, with emphasis on cryogenics and associated repairs and changes on the system components along the time. As concerns the behaviour during operation, the fast safety discharges (FSD) in operation are of particular interest for the Tokamak operation, as they interrupt it for a significant time of the order of 1 h. This aspect is particularly documented. The approach followed to decrease the number of these FSD will be reported and explained. The TORE SUPRA Tokamak was the first important application of superconductivity in plasma physics on a large scale. Overall, despite the differences in design and size, the accumulated experience over 16 years of operation is a useful tool to prepare the manufacture and the operation of the ITER magnets

  6. Routine average effective charge calculation using visible Bremsstrahlung emission and comparison with the impurity transport code of Tore Supra

    International Nuclear Information System (INIS)

    Guirlet, R.; Mattioli, M.; DeMichelis, C.; Hess, W.; Pecquet, A.L.

    1995-01-01

    Effective charge measurements and calculations are presented for the Tore Supra, using visible Bremsstrahlung diagnostics. The measurements, are presented together with a reliability test of the results are discussed, by means of an impurity transport code simulating all available experimental data (XUV line spectroscopy, soft X-ray emission and Bremsstrahlung). (author) 5 refs.; 10 figs

  7. Feasibility study of carbon particles injection by laser ablation to calibrate spectroscopic erosion measurements in Tore Supra

    International Nuclear Information System (INIS)

    Naiim Habib, M.; Mercadier, L.; Marandet, Y.; Delaporte, Ph.; Hernandez, C.; Grisolia, C.; Monier-Garbet, P.

    2011-01-01

    To check if spectroscopic measurements can be used for erosion determination, we propose to inject in the line of sight of the diagnostic, during plasma operation, a known carbon particle source, produced by laser ablation. A first assessment of this technique will be presented in the context of the Tore Supra tokamak.

  8. The control of plasma density profile in Tore Supra. Comparison of different fueling techniques

    International Nuclear Information System (INIS)

    Commaux, N.

    2007-09-01

    The behaviour of a reactor-class plasma when fuelled using the existing techniques (gas puffing, supersonic molecular beam injection and pellet injection) is still very difficult to foresee. The present work has been initiated on Tore Supra in order to extrapolate the consequences of the different fuelling systems on ITER. Two main topics have been studied: the comparison of the plasma behaviour when fuelled using the different techniques at high Greenwald density fractions and the study of the homogenization following a pellet injection (main fuelling technique for ITER burning plasmas). The experiments at high Greenwald density fractions performed on Tore Supra showed that the plasma behaviour is very dependent on the fuelling method. The plasma energy confinement is following the scaling laws determined at low density when fuelled using pellet injection. which is better than for gas puffing and SMBI. both inducing a significant confinement loss. This behaviour is nor related to a transport modification: the ratio between effective diffusion and convection is similar to the pellet case. The difference between these shots is related only to the position of the matter source (at the edge for gas and close to the center for pellets). The study concerning the homogenization phenomena following a pellet injection aims mainly to study the ∇B-drift effect that expels the mater deposited by a pellet toward the low field side. A new phenomenon. which appears to be particularly important for the ∇B-drift during low field side injections. was then discovered: the influence of magnetic surfaces with an integer-valued safety factor (q). When the mater drifting toward low field side crosses an integer q surface. it experiences an important braking effect which stops the drift motion. It implies that the pellet material is mainly deposited on the last integer q surface crossed by the pellet during its injection. This study allows also to determine that the

  9. Fast-wave ICRF minority-regime heating experiments on the Tore Supra tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Agarici, G; Beaumont, B; Becoulet, A; Kuus, H; Saoutic, B; Martin, G [Association Euratom-CEA, Centre d` Etudes Nucleaires de Cadarache, 13 - Saint-Paul-lez-Durance (FR). Dept. de Recherches sur la Fusion Controlee; Shepard, T D; Haste, G R; Baity, F W [Oak Ridge National Lab., TN (US); Evans, T E [General Atomics, San Diego, CA (US)

    1992-12-31

    Up to 4 MW of rf power at 57 MHz has been coupled to Ohmic target plasmas during the first ICRF heating experiments on Tore Supra. A total of 12 MW of rf power will ultimately be available from six tetrode amplifiers and will be coupled to the plasmas using three ORNL/CEA-designed resonant double-loop antennas. During these first experiments, two antennas were used, with one or two energized at a time. The antenna loading with plasma was observed to be well over an order of magnitude greater than that without plasma. In addition, one kilo-electron-volt of electron heating, significant minority nonthermal ions, and significant increases in diamagnetic stored energy were observed. A comparison of in-phase and out-of-phase antenna operation showed the same increase in stored energy, less radiated power, and a larger drop in loop voltage for out-of-phase operation. Confinement scaling agrees with the ITER scaling law.

  10. Study of the electron heat transport in Tore-Supra tokamak

    International Nuclear Information System (INIS)

    Harauchamps, E.

    2004-01-01

    This work presents analytical solutions to the electron heat transport equation involving a damping term and a convection term in a cylindrical geometry. These solutions, processed by Matlab, allow the determination of the evolution of the radial profile of electron temperature in tokamaks during heating. The modulated injection of waves around the electron cyclotron frequency is an efficient tool to study heat transport experimentally in tokamaks. The comparison of these analytical solutions with experimental results from Tore-Supra during 2 discharges (30550 and 31165) shows the presence of a sudden change for the diffusion and damping coefficients. The hypothesis of the presence of a pinch spread all along the plasma might explain the shape of the experimental temperature profiles. These analytical solutions could be used to determine the time evolution of plasma density as well or of any parameter whose evolution is governed by a diffusion-convection equation. (A.C.)

  11. The Tore Supra control, computer system: six years of operation and improvements

    International Nuclear Information System (INIS)

    Journeaux, J.Y.; Badie, O.; Chatelier, E.; Hennion, F.; Lebourg, P.; Leveque, P.; Hernandez, M.; Moulin, D.

    1994-01-01

    Some necessary improvements of the Tore Supra control computer system are discussed. Their main principles are: to choose ergonomic and powerful tools, industrial standards, and to keep the users's participation. The whole control system will be upgraded: the automatism level as well as the display level and the communication networks. A very powerful driving software has been chosen and linked with an expert system, which is to be designed and implemented with the aim to give an immediate accurate and global understanding of the process and situations, in particular in case of trouble. The method is based on an artificial intelligence approach, and it exploits both the process' informations and automatism' steps, to determine the process state, next possible states and diagnosis of the process troubles. (author) 3 refs., 2 figs

  12. Bi-fluid and neoclassical effect on a Double-Tearing mode in Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Maget, Patrick, E-mail: patrick.maget@cea.fr; Garbet, Xavier; Février, Olivier; Ségui, Jean-Luc [CEA, IRFM, F-13108 Saint Paul-lez-Durance (France); Lütjens, Hinrich; Luciani, Jean-François [Centre de Physique Théorique, Ecole Polytechnique, CNRS (France)

    2014-06-15

    Tearing modes associated to hollow current profiles are prone to grow in moderate performance plasmas and often constrain the realization of non-inductive discharges in the Tore Supra tokamak, where long pulse duration is performed using Lower Hybrid waves for providing most of the plasma current. The prediction of MHD boundaries in such scenarios is complicated by the importance of diamagnetic effects, combined with curvature stabilization, which determine the stability of these modes. We show that diamagnetic effects, as well as neoclassical forces, are playing a key role in the linear and nonlinear regimes of Double-Tearing Modes on q = 5/3 and q = 2 in these experimental conditions. Detailed comparison with experimental measurements, combined with a scaling in plasma resistivity, give constraints about the experimental equilibrium. Resistive-Interchange Modes destabilized by diamagnetic rotation could also play a role in degrading the energy confinement in the negative magnetic shear region.

  13. Effects induced by ICRF waves on various confinement schemes in Tore Supra

    International Nuclear Information System (INIS)

    Saoutic, B.

    1995-01-01

    The 1993-94 experimental campaign has seen a significant increase of the application of waves in the ion cyclotron range of frequency on Tore Supra. Ion cyclotron resonant heating has been applied to plasmas with strongly radiating layers, pellet-enhanced performance and lower hybrid enhanced performance. Initial experiments on direct coupling of the fast magnetosonic wave to the electrons have demonstrated coupling up to 5 MW to the plasma and have demonstrated an efficient electron heating in these discharges. A significant bootstrap current fraction is observed. This heating scheme leads to a stationary improvement in energy confinement, with implications for the Rebut-Lallia-Watkins local transport model. Finally, preliminary experiments on antenna phasing have shown clear evidence of fast wave current drive. (author) 25 refs.; 9 figs

  14. Scrape-off profiles and effects of limiter pumping in Tore Supra

    International Nuclear Information System (INIS)

    Budny, R.

    1986-11-01

    A one dimensional plasma scrape-off model was used to simulate Tore Supra discharges which are limited by various combinations of the pumped and inner limiters. Scrape-off profiles of the electron density and temperature, ion temperature, and neutral density are given. For each case, various fractions of the ion flux to the neutralizers were assumed to be pumped. Modifications of the scrap-off profiles caused by pumping are predicted. Pumping efficiencies are calculated including the effects of flux amplification caused by recycling. The pumping efficiency is estimated to be 8% for low-power discharges formed on the outer pumped limiter, 7.5% for intermediate-power discharges formed on the seven-module pumped-limiter system, and 5% for full-power discharges formed on both the inner limiter and the pumped-limiter system. The maximum particle removal rate is estimated to be 150 Tl/s

  15. Runaway electron damage to the Tore Supra Phase III outboard pump limiter

    International Nuclear Information System (INIS)

    Nygren, R.; Lutz, T.; Walsh, D.; Martin, G.; Chatelier, M.; Loarer, T.; Guilhem, D.

    1996-01-01

    Operation of the Phase III outboard pump limiter (OPL) in Tore Supra in 1994 was terminated prematurely when runaway electrons during the current decay following a disruption pierced leading edge tube on the electron side and caused a water leak. The location, about 20 mm outside the last closed flux surface during normal operation, and the infrared (IR) images of the limiter indicate that the runaways moved in large outward steps, i.e. tens of millimeters, in one toroidal revolution. For plasma (runaway) currents in the range of 155 to 250 kA, the drift orbits open to the outside. Basic trajectory computations suggest that such motion is possible under the conditions present for this experiment. Activation measurements made on sections of the tube to indicate the area of local damage are presented here. An understanding of this event may provide important guidance regarding the potential damage from runaways in future tokamaks

  16. Test model of the fast thyristor circuit breaker, for TORE SUPRA

    International Nuclear Information System (INIS)

    Bareyt, B.; Leloup, C.; Rijnoudt, E.

    1984-01-01

    The tokamak TORE SUPRA, permits, owing to the toroidal superconducting coils and to the poloidal field system performances, long discharges (30 s and more), for a plasma current of typically 2 MA. The poloidal field system uses the magnetic energy initially stored, for the ignition and the fast rise of the plasma current, by forcing the primary current to flow through a resistor after breaking the main rectifier current by a fast thyristor circuit breaker. In order to test the technical capabilities of such a breaker system made of fast thyristors, in series and in parallel, after a single thyristor test model T1 the series arrangement was studied on a 24 thyristor test model T2 and the parallel arrangement problems, led the manufacturer CGEE Alsthom, to build a new test model T3. (author)

  17. Measurements of RF-induced sol modifications in Tore Supra tokamak

    International Nuclear Information System (INIS)

    Kubic, Martin; Gunn, James P.; Colas, Laurent; Heuraux, Stephane; Faudot, Eric

    2012-01-01

    Since spring 2011, one of the three ion cyclotron resonance heating (ICRH) antennas in the Tore Supra (TS) tokamak is equipped with a new type of Faraday screen (FS). Results from Radio Frequency (RF) simulations of the new Faraday screen suggest the innovative structure with cantilevered bars and 'shark tooth' openings significantly changes the current flow pattern on the front of the antenna which in turn reduces the RF potential and RF electrical field in particular parallel to the magnetic field lines which contributes to generating RF sheaths. Effects of the new FS operation on RF-induced scrape-off layer (SOL) modifications are studied for different plasma and antenna configurations - scans of strap power ratio imbalance, phasing, injected power and SOL density. (authors)

  18. Real time plasma feedback control: An overview of Tore-Supra achievements

    International Nuclear Information System (INIS)

    Martin, G.; Bucalossi, J.; Ekedahl, A.; Gil, C.; Grisolia, C.; Guilhem, D.; Gunn, J.; Kazarian, F.; Moulin, D.; Pascal, J.Y.; Saint-Laurent, F.

    2001-01-01

    Stable and reliable fusion plasma operation requires increasingly advanced control systems. This is especially true for steady-state operation in advanced modes, when several parameters are to be simultaneously optimised: e.g. the current profile, which has been related to the formation of internal transport barrier, and the density, which plays a crucial role both in the fusion power and in the plasma wall interactions. At a more technological level, good management of the power entering and leaving the plasma is required, by efficient additional heating coupling, and with a full control of radiation and convection losses and distribution to the first wall elements. For these goals, several feed-back mechanisms have been developed with success on Tore-Supra, in the past four years. Most of them are based on software, implemented in a set of micro-computers connected through a VME network. (author)

  19. Determination of q during sawtooth from inverse evolution of BAEs in Tore Supra

    Science.gov (United States)

    Amador, C. H. S.; Sabot, R.; Garbet, X.; Guimarães-Filho, Z. O.; Ahn, J.-H.

    2018-01-01

    Measuring the value of the safety factor (q) in the core during sawtooth cycles is still an open issue. A new method to measure q in Tore Supra plasma core is presented here. It relies on the analysis of the time evolution of a set of MHD modes detected after the sawtooth crashes. These modes are in the frequency range of previously observed Beta-induced Alfvén Eigenmodes, but with a frequency declining in time. The mode frequency analysis shows that the q profile is reversed when we have ICRH, after the sawtooth crash. In high current discharges (I_p>1.15 MA), the q-profile remains reversed for a longer time compared with lower plasma current discharges. Non-linear 3D MHD simulations of sawteeth performed with the XTOR-2F code (Lütjens and Luciani 2010 J. Comput. Phys. 229 8130-43) exhibit features that are similar to these observations.

  20. Multiscale study of the porosity of carbon deposits collected in Tore Supra

    International Nuclear Information System (INIS)

    Martin, C.; Richou, M.; Saikaily, W.; Pegourie, B.; Brosset, C.; Roubin, P.

    2007-01-01

    Carbon deposits collected in Tore Supra, on the neutralisers and on the toroidal pump limiter, are analysed by adsorption isotherm measurements and electron microscopy. Both techniques are suitable to study the porosity in a multiscale range and allow the characterisation of the volume and the structure of the pore network. The neutraliser deposits show an oval shape structure and a high specific surface area. This area corresponds to microporosity, i.e. pores with a typical size lower than 2 nm, (∼11%), mesoporosity (∼5%) and macroporosity, i.e. pores with a typical size more than 50 nm. Surprisingly, transmission electron microscopy performed on thin foils cut from an oval reveals a regular network of parallel slit-shaped mesopores (size ∼ 10 nm) and macropores (size ∼ 100 nm), with a well-defined orientation with respect to the oval axis

  1. The 3 MW ECRH/ECCD transmission and launching system on TORE SUPRA

    International Nuclear Information System (INIS)

    Lennholm, M.; Agarici, G.; Berger-By, G.; Bosia, P.; Bouquey, F.; Clary, J.; Darbos, C.; Giruzzi, G.; Jung, M.; Magne, R.; Roux, D.; Petit, T.; Segui, J.L.; Zou, X.L.

    2003-01-01

    The ECRH experiment on TORE SUPRA is designed to inject up to 3 MW of power at 118 GHz using an antenna consisting of six fixed spherical mirrors and three mobile steering mirrors. The position of the mobile mirrors can be varied in real time using two stepper motors for each mobile mirror. In addition to controlling the injection angle, the position of the mobile mirrors also affects the polarisation of the injected wave. Accurate formulae to compute, in real time, the stepper motor positions required to obtain the desired beam injection angles have been derived. Formulae to determine the effect on the wave polarisation, of the actual mobile mirror positions have also been determined. These formulae have been verified by precise laser measurements and by comparison of power deposition calculations and experimental results. (authors)

  2. Thermal and non-thermal particle interaction with the LHCD launchers in Tore Supra

    International Nuclear Information System (INIS)

    Ekedahl, A.; Goniche, M.; Balorin, C.; Basiuk, V.; Bibet, Ph.; Chantant, M.; Colas, L.; Delpech, L.; Desgranges, C.; Eriksson, L.-G.; Joffrin, E.; Kazarian, F.; Lowry, C.; Moreau, Ph.; Petrzilka, V.; Portafaix, C.; Prou, M.; Roche, H.

    2007-01-01

    The interaction between the lower hybrid current drive (LHCD) launchers and the plasma has been studied during long pulse, high power operation in the Tore Supra tokamak. The main diagnostics used for characterising the plasma-launcher interaction are calorimetry of the energy extracted by the launchers and infrared (IR) imaging of the launchers and their side limiters. The calorimetry has allowed to identify three different heat sources on the LHCD launchers, namely the RF losses in the waveguides, a fraction (∼0.8%) of the total injected energy and, finally, fast ion losses during ion cyclotron resonance heating (ICRH), accounting for ∼1% of the injected ICRH energy. The interaction by fast ions is identified by infrared imaging of the LHCD launchers as a localised hotspot on the ion drift side, below or at the mid-plane

  3. Surface modification and hydrogen isotope retention in CFC during plasma irradiation in the Tore Supra tokamak

    International Nuclear Information System (INIS)

    Begrambekov, L.; Brosset, C.; Bucalossi, J.; Delchambre, E.; Gunn, J.P.; Grisolia, C.; Lipa, M.; Loarer, T.; Mitteau, R.; Moner-Garbet, P.; Pascal, J.-Y.; Shigin, P.; Titov, N.; Tsitrone, E.; Vergazov, S.; Zakharov, A.

    2007-01-01

    The uniform layer with thickness at least 50-100 μm was found on the CFC tiles from the inboard midplane after more than four years of tokamak operation. The upper part of the uniform layer was amorphous, but at the depth of ∼5 μm a structure consisting of micro-size regions with aromatic chains located parallel to the surface was found. Gradual transition from uniform layer to underlying CFC structure was observed. The reciprocating material probe was used for installation of CFC samples in the Tore Supra deuterium plasma. The thermal desorptional spectra of these samples are compared with the spectra of the samples irradiated in the laboratory stand and with the spectra of hydrogenated carbon film. The peculiarities of hydrogen isotope trapping under plasma irradiation and at the atmosphere are presented and discussed

  4. Effects of ionizing scrape-off layers on local recycling in Tore Supra pump limiter experiments

    International Nuclear Information System (INIS)

    Owen, L.W.; Hogan, J.T.; Klepper, C.C.; Mioduszewski, P.K.; Uckan, T.; Chatelier, M.; Loarer, T.

    1992-01-01

    A series of ohmic discharges with active pumping in the Tore Supra outboard pump limiter has been analyzed with the DEGAS neutrals transport code and an analysis scrape-off layer (SOL) plasma model. Pumping speed and plenum pressure measurements indicated 5--10 torr-L/s throughput with only modest effects on density (dN core /dt + source rate from ionization and dissociation of wall-desorbed molecules is seen to peak very near the radial position of the limiter throat. Consequently, a strong recycling vortex is created in the region of the limiter, with the ion flux amplified by factors of ∼2 at the outer limiter surfaces and >3 within the limiter throat. The calculations indicate that less than 30% of the pump throughput is due to first-generation ions from the core efflux, with the balance from local recycling in the strongly ionizing scrape-off layer

  5. Interplay between edge and outer core fluctuations in the tokamak Tore Supra

    International Nuclear Information System (INIS)

    Fenzi, C.; Garbet, X.; Capes, H.; Devynck, P.; Laviron, C.; Truc, A.; Gervais, F.; Hennequin, P.; Quemeneur, A.

    2000-01-01

    In the tokamak Tore Supra, when a poloidally and toroidally localized limiter, called a modular limiter, is introduced into the lower part of the scrape-off layer, density fluctuations located in the vicinity of this limiter present a specific feature with the appearance of a new spectral pattern in the associated frequency spectrum. This leads to a strong up-down asymmetry observed in both the plasma edge and the plasma outer core, with a maximum level of turbulence at the bottom of the plasma. The observed asymmetry characteristics show that magnetic connection lengths play a critical role here and that the limiter configuration has some effect on the outer core turbulence. (author)

  6. Determination of ion temperatures from Zeeman broadened spectral lines in the edge of Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Klepper, C.C.; Isler, R.C.; Tobin, S.J.; Hogan, J.T. [Oak Ridge National Lab., TN (United States). Fusion Energy Div.; Hess, W.R. [Association EURATOM-CEA sur la Fusion Controlee, St-Paul-lez-Durance (France). Centre d`Etudes de Cadarache

    1994-09-01

    The authors have examined a {sup 3}P {yields} {sup 3}S multiplet of C III in Tore Supra in order to assess the possibility of determining the ion temperatures from transitions where the Zeeman effect cannot be neglected compared to the Doppler broadening. The preliminary studies lead them to believe that with good quality data the temperatures can be determined within about 20% in the 20--30 eV range and within about 50% in the neighborhood of 5 eV by fitting the entire multiplet rather than a semi-isolated feature, even though certain parameters important for the analysis, such as polarization effects of the optics, are not well characterized. In order to quantify these conclusions more precisely, future work will concentrate on developing numerical fitting routines and on examining the validity of the assumption that the distribution function for low ionization stages is Maxwellian.

  7. Determination of ion temperatures from Zeeman broadened spectral lines in the edge of Tore Supra

    International Nuclear Information System (INIS)

    Klepper, C.C.; Isler, R.C.; Tobin, S.J.; Hogan, J.T.; Hess, W.R.

    1994-01-01

    The authors have examined a 3 P → 3 S multiplet of C III in Tore Supra in order to assess the possibility of determining the ion temperatures from transitions where the Zeeman effect cannot be neglected compared to the Doppler broadening. The preliminary studies lead them to believe that with good quality data the temperatures can be determined within about 20% in the 20--30 eV range and within about 50% in the neighborhood of 5 eV by fitting the entire multiplet rather than a semi-isolated feature, even though certain parameters important for the analysis, such as polarization effects of the optics, are not well characterized. In order to quantify these conclusions more precisely, future work will concentrate on developing numerical fitting routines and on examining the validity of the assumption that the distribution function for low ionization stages is Maxwellian

  8. Tomography of the fast electron Bremsstrahlung emission during lower hybrid current drive on Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Peysson, Y.; Imbeaux, F. [Association Euratom-CEA, CEA/Cadarache, Dept. de Recherches sur la Fusion Controlee (DRFC), 13 - Saint-Paul-lez-Durance (France)

    1999-04-01

    A new tomography dedicated to detailed studies of the fast electron Bremsstrahlung emission in the hard X-ray (HXR) energy range between 20 and 200 keV during lower hybrid (LH) current drive experiments on the TORE SUPRA tokamak [Equipe TORE SUPRA, in Proceedings of the 15. Conference on Plasma Physics and Controlled Nuclear Fusion Research, Seville (International Atomic Energy Agency, Vienna, 1995), 1, AIEA-CN-60 / A1-5, p. 105] is presented. Radiation detection is performed by cadmium telluride(CdTe) semiconductors, which have most of the desirable features for a powerful diagnosing of magnetically confined hot plasmas - compact size, high X-ray stopping efficiency, fast timing characteristics, good energy resolution, no sensitivity to magnetic field, reasonable susceptibility to performance degradation from neutron/{gamma}-induced damages. This instrument is made of two independent cameras viewing a poloidal cross-section of the plasma, with respectively 21 and 38 detectors. A coarse spectrometry - 8 energy channels - is carried out for each chord, with an energy resolution of 20 keV. The spatial resolution in the core of the plasma is 4-5 cm, while the time sampling may be lowered down to of 2-4 ms. Powerful inversion techniques based on maximum entropy or regularization algorithms take fully advantage of the large number of line-integrated measurements for very robust estimates of the local HXR profiles as a function of time and photon energy. A detailed account of main characteristics and performances of the diagnostic is reported as well as preliminary results on LH current drive experiments. (authors)

  9. High heat flux testing impact on the Tore Supra toroidal pumped limiter achievement

    International Nuclear Information System (INIS)

    Schlosser, J.; Escourbiac, F.; Cordier, J.J.; Mitteau, R.; Durocher, A.; Grosman, A.

    2003-01-01

    The toroidal pumped limiter of Tore Supra is made of 576 elementary high heat flux (HHF) cooled plasma-facing components (PFCs) and designed to sustain 10 MW/m 2 in steady state. One of the main technical difficulties is to ensure a high quality of the bond between the carbon fiber composite armor tile and the water-cooled heat sink due to the high thermal stresses that develop at the bond during operation. Consequently, a HHF facility able to reproduce in service operation of PFCs is required all along the development and manufacturing route. In Europe, the FE200 facility (electron beam, 200 kW, France) operating since 1991, was extensively used for such a development. A first testing campaign in 1995 was devoted to the qualification of this bond: AMC technology from Plansee GmbH was selected. Afterwards, a second campaign on scale-one elements (1996) allowed an optimization of the element design and series production to be launched. During the mass production, a non-destructive control process - cheaper and faster than HHF testing - based on infrared characterization was routinely operated on 100% of the manufactured elements. Strong variability of the bond quality was observed and a repair process allowing the replacement of deficient tiles was developed. In 2000 and 2001, 2 campaigns of HHF testing were launched to correlate the non-destructive measurements and to optimize and validate the repair process. This was done, in two steps, with success. This yielded moreover interesting information for qualifying both tests across each other and also to analyze the fatigue evolution of the bond. The qualification and the achievement of the Tore Supra limiter has greatly been made possible by such HHF tests, which appears as essential before and during PFC manufacturing. (authors)

  10. Feedback control of the lower hybrid power deposition profile on Tore Supra

    International Nuclear Information System (INIS)

    Barana, O; Mazon, D; Laborde, L; Turco, F

    2007-01-01

    The Tore Supra facility is well suited to study ITER relevant topics such as the real-time control of plasma current and the sustaining of steady-state discharges. This work describes a tool that was recently developed and implemented on Tore Supra to control in real time, by means of the direct knowledge of the suprathermal electron local emission profile, the width of the lower hybrid power deposition profile. This quantity can be considered to some extent equivalent to the width of the plasma current density profile in case of fully non-inductive discharges. This system takes advantage of an accurate hard x-ray diagnostics, of an efficient lower hybrid additional heating and of a reliable real-time communication network. The successful experiments carried out to test the system employed, as actuators, the parallel refractive index n // and the total power P LH . The control of the suprathermal electron local emission profile through n // was also integrated with the feedback control of the total plasma current I P with P LH and of the loop voltage V loop with the central solenoid flux. These results demonstrate that the system is robust, reliable and able to counterbalance destabilizing events. This tool can be effectively used in the future in fully non-inductive discharges to improve the MHD stability and to maintain internal transport barriers or lower hybrid enhanced performance modes. The real-time control of the lower hybrid power deposition profile could also be used in conjunction with the electron-cyclotron radiofrequency heating for synergy studies

  11. Tomography of the fast electron Bremsstrahlung emission during lower hybrid current drive on Tore Supra

    International Nuclear Information System (INIS)

    Peysson, Y.; Imbeaux, F.

    1999-04-01

    A new tomography dedicated to detailed studies of the fast electron Bremsstrahlung emission in the hard X-ray (HXR) energy range between 20 and 200 keV during lower hybrid (LH) current drive experiments on the TORE SUPRA tokamak [Equipe TORE SUPRA, in Proceedings of the 15. Conference on Plasma Physics and Controlled Nuclear Fusion Research, Seville (International Atomic Energy Agency, Vienna, 1995), 1, AIEA-CN-60 / A1-5, p. 105] is presented. Radiation detection is performed by cadmium telluride (CdTe) semiconductors, which have most of the desirable features for a powerful diagnosing of magnetically confined hot plasmas - compact size, high X-ray stopping efficiency, fast timing characteristics, good energy resolution, no sensitivity to magnetic field, reasonable susceptibility to performance degradation from neutron/γ-induced damages. This instrument is made of two independent cameras viewing a poloidal cross-section of the plasma, with respectively 21 and 38 detectors. A coarse spectrometry - 8 energy channels - is carried out for each chord, with an energy resolution of 20 keV. The spatial resolution in the core of the plasma is 4-5 cm, while the time sampling may be lowered down to of 2-4 ms. Powerful inversion techniques based on maximum entropy or regularization algorithms take fully advantage of the large number of line-integrated measurements for very robust estimates of the local HXR profiles as a function of time and photon energy. A detailed account of main characteristics and performances of the diagnostic is reported as well as preliminary results on LH current drive experiments. (authors)

  12. Study of heat transfer and particle transport in Tore Supra and HL-2A tokamaks

    International Nuclear Information System (INIS)

    Song, S.

    2011-12-01

    This thesis reports on experimental studies of heat and particles transport performed on 2 large tokamaks: Tore Supra (based at CEA/Cadarache, France) and HL-2A (based at the Southwestern Institute of Physics, Chengdu, China). The modulated source is the Electron Cyclotron Resonance Heating (ECRH) for the heat pinch and density pump-out studies, while the non-local transport experiments use the Supersonic Molecular Beam Injection (SMBI) as source of modulation. The emphasis is put on the inward heat pinch. In the off-axis ECRH modulation experiments on Tore Supra with low frequency (1 Hz), strong heat inward transport has been observed, in particular for low density. Two transport models have been applied in order to analyze the experimental behavior. The first one is the linear pinch model (LPM) and the second one is an empirical model based on micro-instabilities theory, named Critical Gradient Model (CGM). Good agreement has been found for all harmonics between the experimental data and the simulation using LPM. On the other hand, good agreement has not been achieved using CGM. The density pump-out with large particles and energy losses during ECRH is commonly observed in tokamaks. A new dynamic approach using the modulation technique has been used in HL-2A for analyzing the transient phase of the density pump-out. A correlation between the turbulence increase and the density pump-out has been found. The non-local transport phenomenon, characterized by a fast transient process compared to the normal diffusive response to the perturbation is observed. Both phenomena, i.e., pump-out and non-locality, show as simultaneous variation of density and temperature. This can be an inspiration for the usage of a transport matrix which considers the density and temperature evolution together. Simulations with a simple transport matrix, with non-diagonal terms coupling temperature and density qualitatively reproduce the non-local and pump-out effects qualitatively

  13. Deuterium inventory in Tore Supra: reconciling particle balance and post-mortem analysis

    International Nuclear Information System (INIS)

    Tsitrone, E.; Brosset, C.; Pegourie, B.; Gauthier, E.; Bouvet, J.; Bucalossi, J.; Carpentier, S.; Corre, Y.; Delchambre, E.; Dittmar, T.; Douai, D.; Ekedahl, A.; Ghendrih, Ph.; Grisolia, C.; Grosman, A.; Gunn, J.; Hong, S.H.; Desgranges, L.; Escarguel, A.; Jacob, W.

    2009-01-01

    Fuel retention, a crucial issue for next step devices, is assessed in present-day tokamaks using two methods: particle balance performed during shots and post-mortem analysis carried out during shutdowns between experimental campaigns. Post-mortem analysis generally gives lower estimates of fuel retention than integrated particle balance. In order to understand the discrepancy between these two methods, a dedicated experimental campaign has been performed in Tore Supra to load the vessel walls with deuterium (D) and monitor the trapped D inventory through particle balance. The campaign was followed by an extensive post-mortem analysis phase of the Tore Supra limiter. This paper presents the status of the analysis phase, including the assessment of the D content in the castellated tile structure of the limiter. Indeed, using combined surface analysis techniques, it was possible to derive the relative contributions of different zones of interest on the limiter (erosion, thick deposits, thin deposits), showing that the post-mortem inventory is mainly due to codeposition (90% of the total), in particular due to gap deposits. However, deuterium was also evidenced deep into the material in erosion zones (10% of the total). At the present stage of the analysis, 50% of the inventory deduced from particle balance has been found through post-mortem analysis, a significant progress with respect to previous studies (factor 8-10 discrepancy). This shows that post-mortem analysis can be consistent with particle balance provided specific procedures are implemented (dedicated campaign followed by extensive post-mortem analysis). Both techniques are needed for a reliable assessment of fuel retention in tokamaks, giving complementary information on how much and where fuel is retained in the vessel walls.

  14. Energy measurement of fast ions trapped in the toroidal field ripple of Tore Supra

    International Nuclear Information System (INIS)

    Basiuk, V.; Becoulet, A.; Hutter, T.; Martin, G.; Pecquet, A.L.; Saoutic, B.

    1993-09-01

    During additional heating in Tore Supra (ICRF or NBI) fast ion losses due to the toroidal field ripple were clearly measured by a set of graphite probes. This diagnostic collects the flow of fast ions entering a vertical port and usually shows a maximum flux for ions originating from the vicinity of surface δ * = 0. During the monster sawteeth regime, achieved with ICRF, a remarkable phenomenon was observed: the ejection of fast ions, not correlated with any measured MHD activity. The radial distribution of these ions is quite different from that usually observed exhibiting a peak located in the central section of the plasma. In order to measure the energy distribution of these ions, from 80 keV (energy of the neutral beam injected in Tore Supra) up to 1 MeV (expected during ICRF), a new diagnostic is under construction. The principle of the diagnostic is to discriminate the ions in energy using their Larmor radius (p = 1.3 cm for 100 keV → p = 3.6 cm for 700 keV, B = 4T). The detector is made of a hollow graphite cylinder with a small entrance slot, located in a vertical port on the ion drift side. An array of six metallic collectors placed inside the graphite cylinder intercepts the ions. The current on each collector was estimated at 10 → 100 nA, during ICRF heating. The energy resolution of this diagnostic is expected to be about 20 keV for the lowest energy range and 100 keV for the highest. This type of ruggedized detector might be extrapolated for the measurements of alpha particle losses in future DT experiments. It should also be suitable for the studies of stochastic ripple diffusion. (authors). 3 refs., 9 figs

  15. Multi scale study of carbon deposits collected in Tore-Supra and TEXTOR tokamaks; Etude multi echelle des depots carbones collectes dans les tokamaks Tore Supra et TEXTOR

    Energy Technology Data Exchange (ETDEWEB)

    Richou, M

    2007-06-15

    Tokamaks are devices aimed at studying magnetic fusion. They operate with high temperature plasmas containing hydrogen, deuterium or tritium. One of the major issue is to control the plasma-wall interaction. The plasma facing components are most often in carbon. The major drawback of carbon is the existence of carbon deposits and dust, due to erosion. Dust is potentially reactive in case of an accidental opening of the device. These deposits also contain H, D or T and induce major safety problems when tritium is used, which will be the case in ITER. Therefore, the understanding of the deposit formation and structure has become a main issue for fusion researches. To clarify the role of the deposits in the retention phenomenon, we have done different complementary characterizations for deposits collected on similar places (neutralizers) in tokamaks Tore Supra (France) and TEXTOR (Germany). Accessible microporous volume and pore size distribution of deposits has been determined with the analysis of nitrogen and methane adsorption isotherms using the BET, Dubinin-Radushkevich and {alpha}{sub s} methods and the Density Functional Theory (DFT). To understand growth mechanisms, we have studied the deposit structure and morphology. We have shown using Transmission Electron Microscopy (TEM) and Raman micro-spectrometry that these deposits are non amorphous and disordered. We have also shown the presence of nano-particles (diameter between 4 and 70 nm) which are similar to carbon blacks: nano-particle growth occurs in homogeneous phase in the edge plasma. We have emphasised a dual growth process: a homogenous and a heterogeneous one. (author)

  16. Scientific feedback from high heat flux actively cooled PFCs development, realization and first results in Tore Supra

    International Nuclear Information System (INIS)

    Grosman, A.; Bayetti, P.; Brosset, C.; Bucalossi, J.; Cordier, J.J.; Durocher, A.; Escourbiac, F.; Ghendrih, Ph.; Guilhem, D.; Gunn, J.; Loarer, T.; Lipa, M.; Mitteau, R.; Pegourie, B.; Reichle, R.; Schlosser, J.; Tsitrone, E.; Vallet, J.C.

    2004-01-01

    The implementation of actively cooled high heat flux plasma facing components (PFCs) are one of the major ingredients required for operating the Tore Supra tokamak with very long pulses. A pioneering activity has been developed in this field from the very beginning of the device operation that is today culminating with the routine operation of an actively cooled toroidal pumped limiter (TPL) capable to sustain up to 10 MW.m -2 of nominal convected heat flux. A technical feedback is given from the whole development up to the industrialization and focuses on a number of critical issues, such as bonding technology analysis, manufacture processes, repair processes, destructive and non destructive testing. The actual experience in Tore Supra allows to address the question of D retention on carbon walls. Redeposition on surfaces without plasma flux is suspected to cause the final 'burial' of about the injected gas during long discharges. (authors)

  17. Scientific feedback from high heat flux actively cooled PFCs development, realization and first results in Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Grosman, A.; Bayetti, P.; Brosset, C.; Bucalossi, J.; Cordier, J.J.; Durocher, A.; Escourbiac, F.; Ghendrih, Ph.; Guilhem, D.; Gunn, J.; Loarer, T.; Lipa, M.; Mitteau, R.; Pegourie, B.; Reichle, R.; Schlosser, J.; Tsitrone, E.; Vallet, J.C

    2004-07-01

    The implementation of actively cooled high heat flux plasma facing components (PFCs) are one of the major ingredients required for operating the Tore Supra tokamak with very long pulses. A pioneering activity has been developed in this field from the very beginning of the device operation that is today culminating with the routine operation of an actively cooled toroidal pumped limiter (TPL) capable to sustain up to 10 MW.m{sup -2} of nominal convected heat flux. A technical feedback is given from the whole development up to the industrialization and focuses on a number of critical issues, such as bonding technology analysis, manufacture processes, repair processes, destructive and non destructive testing. The actual experience in Tore Supra allows to address the question of D retention on carbon walls. Redeposition on surfaces without plasma flux is suspected to cause the final 'burial' of about the injected gas during long discharges. (authors)

  18. Study on the materials for mirrors and back mirror reflectors of thermonuclear reactors and their testing in Tore-Supra

    International Nuclear Information System (INIS)

    Schunke, B.; Voytsenya, V.; Gil, C.; Lipa, M.

    2003-01-01

    Plasma diagnostics using visible or ultra-violet or infra-red radiations require mirrors to probe the plasma. These mirrors have to sustain very hostile environment and despite that must maintain good optical properties. Mirror samples made of 3 different metals: copper, stainless steel and molybdenum have been designed and installed in Tore Supra tokamak and will be exposed to plasmas till mid 2004. This project will allow fusion engineers to assess the impact of plasma ion bombardment on mirror reflectivity. Optical properties and parameters concerning the surface state of the samples have been measured before the installation in Tore Supra and are presented in the paper. Simulations with a Monte-Carlo code predict the particle flux and spectra near the samples. A specific back mirror reflector has been designed to probe mirror reflectivity changes. (A.C.)

  19. Evidence for a poloidally localized enhancement of radial transport in the scrape-off layer of the Tore Supra tokamak

    Czech Academy of Sciences Publication Activity Database

    Gunn, J. P.; Boucher, C.; Dionne, M.; Ďuran, Ivan; Fuchs, Vladimír; Loarer, T.; Nanobashvili, I.; Pánek, Radomír; Pascal, J.-Y.; Saint-Laurent, F.; Stöckel, Jan; Van Rompuy, T.; Zagórski, R.; Adámek, Jiří; Bucalossi, J.; Dejarnac, Renaud; Devynck, P.; Hertout, P.; Hron, Martin; Lebrun, G.; Moreau, P.; Rimini, F.; Sarkissian, A.; Van Oost, G.

    363-365, - (2007), s. 484-490 ISSN 0022-3115. [International Conference on Plasma-Surface Interactions in Controlled Fusion Devices/17th./. Hefei, 22.05.2006-26.05. 2006] R&D Projects: GA ČR GP202/03/P062 Institutional research plan: CEZ:AV0Z20430508 Keywords : Cross-field transport * Edge plasma * Plasma flow * Tore Supra Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.643, year: 2007

  20. Measurements of scrape-off layer ion-to-electron temperature ratio in Tore Supra ohmic plasmas

    Czech Academy of Sciences Publication Activity Database

    Kočan, M.; Gunn, J. P.; Pascal, J.-Y.; Bonhomme, G.; Devynck, P.; Ďuran, Ivan; Gauthier, E.; Ghendrih, P.; Marandet, Y.; Pegourie, B.; Vallet, J.-C.

    390-391, - (2009), s. 1074-1077 ISSN 0022-3115. [International Conference on Plasma-Surface Interactions in Controlled Fusion Devices/18th./. Toledo, 26.05.2008-30.05. 2008] Institutional research plan: CEZ:AV0Z20430508 Keywords : Ion temperature * Electron temperature * Edge plasma * Tore Supra Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.933, year: 2009

  1. Stochastic field line structures appearing in field line tracing calculations for a helical magnetic limiter on TORE SUPRA

    International Nuclear Information System (INIS)

    Fuchs, G.; Steffen, B.; Blenski, T.; Grosman, A.; Samain, A.

    1985-05-01

    The influence on the structure of the magnetic field of a tokamak produced by small helical currents flowing near the plasma in TORE SUPRA was investigated numerically by drawing Poincare plots. The current in the helical conductors, the pitch of the windings, the rotational transform and the plasma pressure have been varied. The topology of the magnetic field line structure is discussed in some detail and simple examples are given for illustration. (orig.)

  2. Deuterium Inventory in Tore Supra (DITS): 2nd post-mortem analysis campaign and fuel retention in the gaps

    International Nuclear Information System (INIS)

    Dittmar, T.; Tsitrone, E.; Pegourie, B.; Cadez, I.; Pelicon, P.; Gauthier, E.; Languille, P.; Likonen, J.; Litnovsky, A.; Markelj, S.; Martin, C.; Mayer, M.; Pascal, J.-Y.; Pardanaud, C.; Philipps, V.; Roth, J.; Roubin, P.; Vavpetic, P.

    2011-01-01

    A dedicated study on fuel retention has been launched in Tore Supra, which includes a D wall-loading campaign and the dismantling of the main limiter (Deuterium Inventory in Tore Supra, DITS project). This paper presents new results from a second post-mortem analysis campaign on 40 tiles with special emphasis on the D retention in the gaps. SIMS analysis reveals that only 1/3 of the thickness of deposits in the plasma shadowed zones are due to the DITS wall-loading campaign. As pre-DITS deposits contain less D than DITS deposits, the contribution of DITS to the D inventory is about 30-50%. The new estimate for the total amount of D retained in the Tore Supra limiter is 1.7 x 10 24 atoms, close to the previous estimate, with the gap surfaces contributing about 33%. NRA measurements show a stepped decrease of D along the gap with strong asymmetries between different gap orientations.

  3. Experimental study of turbulence on Tore Supra by plasma micro-waves interaction; Etude experimentale de la turbulence sur Tore Supra par interaction plasma micro-ondes

    Energy Technology Data Exchange (ETDEWEB)

    Colas, L

    1996-09-23

    Internal small-scale magnetic turbulence is a serious candidate to explain the anomalous heat transport in tokamaks. This turbulence is badly known in the gradient region of large machines. In this work internal magnetic fluctuations are measured on Tore Supra with an original diagnostic : Cross Polarization Scattering (CPS). This experimental tool relies on the Eigenmode change of a probing polarised microwave beam scattered by magnetic fluctuations, close to a cut-off layer for the incident wave. In this work, the diagnostic is first qualified to assess its sensitivity to magnetic fluctuations, and the spatial localisation for its measurements. The magnetic fluctuation behaviour is then analysed over a wide range of plasma current, density and additional power, and interpreted with a simple 1-D scattering model. A scan of the plasma density or magnetic field is used to move the CPS measurement location from r/a = 0.3 to r/a = 0.75. A fluctuation radial profile is obtained by two means. In L-mode discharges, the relation between magnetic fluctuations, temperature profiles and local heat diffusivities is investigated. With all measurements, it is also possible to look for a local parameter correlated to the turbulence in a large domain of plasma conditions. The fluctuation-induced local heat diffusivity expected from the measured fluctuations is estimated using the non-collisional quasi-linear formula: X{sup mag}{sub e} = {pi}qRV{sub te}({delta}B / B){sup 2}. Both the absolute values and the parametric dependence of calculated X{sup mag}{sub e} are close to the electron thermal diffusivities Xe determined by transport analysis. In particular, a threshold is evidenced in the dependence of fluctuation-induced heat fluxes on local {nabla}T{sub e}, which is analogous to the critical gradient for measured heat fluxes. The experimental setup is also sensitive to the Thomson scattering of the probing wave by density fluctuations. Its measurements are analysed as the

  4. Study of the chemical sputtering in Tore-Supra; Etude de l'erosion chimique dans le tokamak Tore-Supra

    Energy Technology Data Exchange (ETDEWEB)

    Cambe, A

    2002-06-28

    The work presented in this thesis focuses on the interactions between energetic particles coming from thermonuclear plasma and the inner components of a fusion machine. This interaction induces two major problems: erosion of the wall, and tritium retention. This report treats the erosion of carbon based materials. The first part is devoted to chemical sputtering, that appears to be the principal erosion mechanism, compared to physical sputtering and radiation enhanced sublimation that both can be limited. Chemical sputtering has been studied in situ in the tokamak Tore-Supra for ohmic and lower hybrid (LH) heated discharges, by means of mass spectrometry and optical spectroscopy. We have shown that it is necessary to take into account both methane and heavier hydrocarbons (C{sub 2}D{sub x} and C{sub 3}D{sub y}) in the determination of the chemical sputtering yield. It is found that for the ohmic discharges, the sputtering yield of CD{sub 4} (Y{sub CD4}) is highly flux ({phi}) dependent, showing a variation of the form: Y{sub CD4} {proportional_to} {phi}{sup -0.23}. The experimental study also reveals that an increase of the surface temperature induces an augmentation of Y{sub CD4}. The interpretation and the modelling of the experimental results have been performed with a Monte Carlo code (BBQ. In the second part of this work, we have developed and installed an infrared spectroscopy diagnostic in the 0.8-1.6, {mu}m wavelength range dedicated to the measurement of surface temperature, and the identification of atomic and molecular lines emitted during plasma/wall interactions. In the third part, we present the feasibility study of an in situ tungsten deposition process at low temperature(<80 deg C) in order to suppress the chemical sputtering. This study shows that, with this method call Plasma Assisted Chemical Vapor Deposition (PACVD), we are able to coat the whole inner vessel of a tokamak with 1 {mu}m of tungsten. (author)

  5. Evaluation of the growth of carbonaceous deposit in steady state Tore Supra using infrared thermography

    International Nuclear Information System (INIS)

    Mitteau, R.; Guilhem, D.; Reichle, R.; Vallet, J.C.; Roche, H.; Buravand, Y.; Chantant, M.; Tsitrone, E.; Brosset, C.; Grosman, A.; Chappuis, P.

    2006-01-01

    Fusion devices with carbon as the main armour material are experiencing a growth in carbonaceous deposits at the surface of the plasma facing components. Tore Supra presents such deposits, and has specific features which influence their growth: long pulse operation and cooled walls. Deposits have a low thermal transfer to the cooled structure so that they appear as hot areas with the infrared imaging system looking at the elements surface temperature during plasma discharges. A 'degree of (carbon) deposit' on the toroidal pumped limiter is estimated by establishing the ratio between the apparent power on the limiter derived from the infrared measure and the actual one, deduced from a power balance analysis between the injected and the radiated power. This criterion is used to monitor the evolution of the deposit average thermal resistance. Successive shots have a similar 'degree of deposit', showing that the evaluation makes sense. Two years of data have been compiled (2003 and 2004), representing 3000 discharges (13 h of plasma, including 30 discharges longer than one minute). A three-fold increase in the 'degree of deposit' over six months is evidenced, following a limiter clean-up early in 2003. A comparison with calorimetric data produces a similar result, albeit less pronounced. Large steps in the degree of deposit are sometimes observed, usually correlated with identified events such as disruption, vessel opening, conditioning or plasma parameters change. It indicates that the deposit thermal resistance can change rapidly, although a systematic correlation with the above mentioned events could not be established

  6. Scanning electron microscopy characterisation of carbon deposited layers in Tore Supra

    International Nuclear Information System (INIS)

    Delchambre, E.; Brosset, C.; Reichle, R.; Devynck, P.; Guirlet, R.; Tsitrone, E.; Saikali, W.; Dominici, C.; Charai, A.

    2003-01-01

    For long discharges in Tore-Supra, an infra-red safety system has been installed to survey surface temperature of the target plates located below the toroidal pump limiter. A shift in temperature is attributed to the growth of a carbon layer at the surface of the neutralizer and has been estimated to a temperature increase of 400 Celsius degrees between virgin and layered surfaces. For temperature safety analysis, target plates have been cleaned and carbon layers were sampled for scanning electronic microscopy (SEM) study. SEM micrographs have allowed to measure the deposited layer thickness and to study the specific fractal and stratified structure. Energy dispersive X-ray spectroscopy analysis has permitted to distinguish carbon layers corresponding to boronization and then to deduce an average growth rate of about 20 nm/s. The growth rate is not constant and is likely to depend on plasma operation parameters. These analyses completed by time of flight secondary ions mass spectrometry (ToF-SIMS) have shown a beneficial effect of the boronization on metallic contamination of the plasma, confirming the in situ optical spectroscopic measurements. These analyses have also shown an increase of hydrogen storage in carbon layer due to boronization. Although the measurements performed on deposited layer are very local, the results reflect the history of the 2002 campaign. (A.C.)

  7. Assessing braze quality in the actively cooled Tore Supra phase III outboard pump limiter

    International Nuclear Information System (INIS)

    Hygren, R.; Lutz, T.; Miller, J.

    1994-01-01

    This paper discusses the assessment of quality of brazing of pyrolytic graphite (PG) armor brazed to copper tubes in Tore Supra's Phase III Outboard Pump Limiter (OPL). The limiter head is a bank of 14 water-cooled copper tubes with several hundred brazed PG tiles. Braze quality was first assessed through pre-service qualification testing of individual copper/tiles assemblies. The quality of brazes was evaluated using (non-destructive) transient heating (open-quotes hot waterclose quotes) tests performed in the high temperature, high pressure flow loop at Sandia's Plasma Materials Test Facility. The surface temperatures of tiles were monitored with an infra-red (IR) camera as water at 120 degrees C water at about 2.07 MPa (300 psi) passed through a tube assembly initially at 30 degrees C. For tiles with braze voids or cracks, the surface temperatures lagged behind those of adjacent well bonded tiles. Temperature lags were correlated with flaw sizes observed during repairs using a detailed 2-D heat transfer analyses. open-quotes Badclose quotes tiles, i.e., temperature lags of 10-20 degrees C depending upon tile's size, were easy to detect and, when removed, revealed braze voids of roughly 50% of the joint area. 11 of the 14 tubes were rebrazed after bad tiles were detected and removed. Three tubes were re-brazed twice

  8. Kinetic Monte-Carlo modeling of hydrogen retention and re-emission from Tore Supra deposits

    International Nuclear Information System (INIS)

    Rai, A.; Schneider, R.; Warrier, M.; Roubin, P.; Martin, C.; Richou, M.

    2009-01-01

    A multi-scale model has been developed to study the reactive-diffusive transport of hydrogen in porous graphite [A. Rai, R. Schneider, M. Warrier, J. Nucl. Mater. (submitted for publication). http://dx.doi.org/10.1016/j.jnucmat.2007.08.013.]. The deposits found on the leading edge of the neutralizer of Tore Supra are multi-scale in nature, consisting of micropores with typical size lower than 2 nm (∼11%), mesopores (∼5%) and macropores with a typical size more than 50 nm [C. Martin, M. Richou, W. Sakaily, B. Pegourie, C. Brosset, P. Roubin, J. Nucl. Mater. 363-365 (2007) 1251]. Kinetic Monte-Carlo (KMC) has been used to study the hydrogen transport at meso-scales. Recombination rate and the diffusion coefficient calculated at the meso-scale was used as an input to scale up and analyze the hydrogen transport at macro-scale. A combination of KMC and MCD (Monte-Carlo diffusion) method was used at macro-scales. Flux dependence of hydrogen recycling has been studied. The retention and re-emission analysis of the model has been extended to study the chemical erosion process based on the Kueppers-Hopf cycle [M. Wittmann, J. Kueppers, J. Nucl. Mater. 227 (1996) 186].

  9. Dynamic Monte-Carlo modeling of hydrogen retention and chemical erosion from Tore Supra deposits

    International Nuclear Information System (INIS)

    Rai, A.; Schneider, R.; Warrier, M.; Roubin, P.; Martin, C.

    2009-01-01

    A multi-scale model has been developed to study the hydrogen retention [A. Rai, R. Schneider, M. Warrier, J. Nucl. Mater. 374 (2008) 304] and chemical erosion of porous graphite. To model the chemical erosion process due to thermal hydrogen ions, Kueppers cycle [J. Kueppers, Surf. Sci. Rep. 22 (1995) 249; M. Wittmann, J. Kueppers, J. Nucl. Mater. 227 (1996) 186] has been introduced. The model is applied to study hydrogen transport in deposits collected from the leading edge of neutralizers of Tore Supra. The effect of internal structure on chemical erosion is studied. The MD study [E. Salonen et al., J. Nucl. Mater. 290-293 (2001) 144] shows that the experimentally observed decrease of erosion yield at higher fluxes is due to the decrease of carbon collision cross-section at a surface due to shielding by hydrogen atom already present on the surface. Inspired by this study, a simple multi-scale model is developed to describe the flux dependence of chemical erosion. The idea is to use the local chemistry effect from the Kueppers model to calculate the hydrocarbon molecule formation process and then to find the release probability of the produced hydrocarbon based on the purely geometrical constraints. The model represents quite well the trends in experimental data.

  10. Power exhaust and edge control in steady state tore supra plasma

    International Nuclear Information System (INIS)

    Mitteau, R.; Guilhem, D.; Vallet, J.C.

    2003-01-01

    Tore Supra is operated since 2001 with a toroidal limiter designed to remove continuously a heat power of 15 MW at a maximum (ITER relevant) heat flux density of 10 MW/m 2 . The limiter is located in the bottom of the vacuum vessel and is actively cooled by a pressurised water loop. For an injection of 6 MW of additional power, the limiter extracts 3.6 MW and the surface temperature stabilises typically at 400 deg C in 5 seconds during discharges lasting up to 260 seconds. The maximum heat flux density reach 3 MW/m 2 which is still modest compared to the design value, but nevertheless enables a comparison to the modelling. Heat flux and deposition pattern are in very good accordance with design simulations. Additional heat load concentrations specific to radio-frequency heating superimpose to the convection heat load at levels that are commensurable with the elements thermal capability. Insights on the tiles behaviour are given. Operation with such a large size high heat flux component sets an renewed emphasis on issues such as feed back systems, active security, cooling parameters and in situ assessment of the elements. These issues are dealt with in this paper. (author)

  11. Power deposition to the pump limiters in Tore-Supra with ohmic plasmas

    International Nuclear Information System (INIS)

    Guilhem, D.; Chatelier, M.; Chappuis Fleury, I.; Klepper, C.

    1990-01-01

    The modification of power scrape-off-length, λq, and power deposition are studied both with the horizontal limiter alone and with the full set of 7 pump limiters for 1MW ohmic plasmas in TORE-SUPRA. By making spatially resolved infrared surface temperature measurements during the plasma discharge, the magnitude and distribution of the energy flux can be derived. For comparison, the surface temperature of the horizontal pump limiter is calculated with a finite element code using a 3D description of the field lines, an exponential scrape-off-layer, and the pump limiter geometry. From comparison of the infrared images of the limiter we derived that the λq for power deposition was slightly less than 9 mm (±1mm) which is in agreement with the predicted design value of 10 mm. For an 8 seconds discharge, the maximum surface temperature on the horizontal limiter is 450 0 C. Inserting the 7 limiters does not modify λq (which becomes 10 mm). The power is shared by all the limiters and the maximum surface temperature on the horizontal limiter decreased to 320 0 C. These λq values have been independently measured by the integrated energy deposition on the horizontal limiter and other internal structures 5 cm into the scrape-off layer. These values agree with the infrared measurements in the two cases

  12. Coupling between particle and heat transport during power modulation experiments in Tore Supra

    International Nuclear Information System (INIS)

    Zou, X.L.; Giruzzi, G.; Artaud, J.F.; Bouquey, F.; Bremond, S.; Clary, J.; Darbos, C.; Eury, S.P.; Lennholm, M.; Magne, R.; Segui, J.L.

    2004-01-01

    Power modulations are a powerful tool often used to investigate heat transport processes in tokamaks. In some situations, this could also be an interesting method for the investigation of the particle transport due to the anomalous pinch. Low frequency (∼ 1 Hz) power modulation experiments, using both electron cyclotron resonance heating (ECRH) and ion cyclotron resonance heating (ICRH), have been performed in the Tore Supra tokamak. Strong coupling has been observed between the temperature and density modulations during the low frequency ECRH and ICRH modulation experiments. It has been shown that mechanisms as outgassing, Ware pinch effect, curvature driven pinch are not likely to be responsible for this density modulation. Because of its dependence on temperature or temperature gradient, the thermodiffusion is a serious candidate to be the driving source for this density modulation. This analysis shows that low frequency power modulation experiments have a great potential for the investigation of the anomalous particle pinch in tokamaks. Future plans will include the use of more precise density profile measurements using X-mode reflectometry

  13. 2-D mapping of ICRF-induced SOL perturbations in Tore Supra tokamak

    International Nuclear Information System (INIS)

    Colas, L.; Gunn, J.P.; Nanobashvili, I.; Petrzilka, V.; Goniche, M.; Ekedahl, A.; Heuraux, S.; Joffrin, E.; Saint-Laurent, F.; Balorin, C.; Lowry, C.; Basiuk, V.

    2007-01-01

    ICRF-induced SOL modifications are mapped for the first time in 2-D around Tore Supra ICRF antennas using reciprocating Langmuir probes. When probe heads are magnetically connected to powered antennas, radical modifications of floating potentials V float , effective temperatures T eff and ion saturation currents are observed. V float perturbations are located radially near antenna limiters, with a typical extension 2 cm. Poloidally they are locally minimal near the equatorial plane, and maximal near antenna box corners. Two possible interpretations for increased T eff are proposed: localised electron heating and RF loop voltage induced along probe circuit. Both interpretations rely on the generation of parallel RF fields by parallel RF currents on the antenna structure. The topology of such currents could explain the 2-D structure of T eff maps. Both interpretations also imply a positive DC biasing of the antenna environment. Differential biasing of nearby flux tubes drives DC E x B 0 convection that could explain 2-D density patterns

  14. Closed Loop Sawtooth Period Control Using Variable Eccd Injection Angles on Tore Supra

    International Nuclear Information System (INIS)

    Lennholm, M.; Eriksson, L.G.; Turco, F.; Bouquey, F.; Darbos, C.; Dumont, R.; Giruzzi, G.; Jung, M.; Lambert, R.; Magne, R.; Molina, D.; Moreau, P.; Rimini, F.; Segui, J.L.; Song, S.; Traisnel, E.

    2009-01-01

    Closed loop control of the period of fast ion stabilized sawtooth has been demonstrated for the first time on Tore Supra by varying the electron cyclotron current drive (ECCD) injection angles in real time. Fast ions generated by up to 4 MW of central ion cyclotron resonance heating (ICRH) increased the sawtooth period from the ohmic value of 25 ms to 60 to 100 ms. This sawtooth period was reduced to 30 ms by the addition of only 300 kW of ECCD. In ICRH heated shots where the normalized minor radius of the ECCD absorption location was swept from 0.4 to 0.05 in 4 s, the sawtooth period showed an abrupt change from 70 to 30 ms when the ECCD deposition normalized minor radius reached ∼ 0.2. This short period was then maintained until the absorption location moved well inside the sawtooth inversion radius at which point it abruptly returned to 70 ins. A closed loop controller was implemented that allowed the sawtooth period to be switched in real time between short and long sawteeth with a response time of the order of 1 s. (authors)

  15. Spectral broadening measurement of the lower hybrid waves during long pulse operation in Tore Supra

    Science.gov (United States)

    Berger-By, G.; Decampy, J.; Antar, G. Y.; Goniche, M.; Ekedahl, A.; Delpech, L.; Leroux, F.; Tore Supra Team

    2014-02-01

    On many tokamaks (C-Mod, EAST, FTU, JET, HT-7, TS), a decrease in current drive efficiency of the Lower Hybrid (LH) waves is observed in high electron density plasmas. The cause of this behaviour is believed to be: Parametric Instabilities (PI) and Scattering from Density Fluctuations (SDF). For the ITER LH system, our knowledge must be improved to avoid such effects and to maintain the LH current drive efficiency at high density. The ITPA IOS group coordinates this effort [1] and all experimental data are essential to validate the numerical codes in progress. Usually the broadening of the LH wave frequency spectrum is measured by a probe located in the plasma edge. For this study, the frequency spectrum of a reflected power signal from the LH antenna was used. In addition, the spectrum measurements are compared with the density fluctuations observed on RF probes located at the antenna mouth. Several plasma currents (0.6 to 1.4 MA) and densities up to 5.2 × 1019 m-3 have been realised on Tore Supra (TS) long pulses and with high injected RF power, up to 5.4 MW-30s. This allowed using a spectrum analyser to make several measurements during the plasma pulse. The side lobe amplitude, shifted by 20-30MHz with respect to the main peak, grows with increasing density. Furthermore, for an increase of plasma current at the same density, the spectra broaden and become asymmetric. Some parametric dependencies are shown in this paper.

  16. New managing system of a large amount of images on Tore Supra

    International Nuclear Information System (INIS)

    Buravand, Y.; Ducobu, L.; Guilhem, D.; Roche, H.; Signoret, J.; Travere, J.M.; Utzel, N.

    2004-01-01

    After a major replacement of all internal components (terminated in 2002), Tore Supra has restarted operation with a new set of actively cooled components. The safety of these components relies on infrared (IR) thermography. Up to twelve IR cameras will be used to survey nearly all the high flux target zones which are essentially the 360 deg C toroidal pump limiter and the 5 power injection HF antennas. The high data rate produced by each camera ( ∼ 8 Mbytes/sec.) led us to implement a multi stages system: during experimentations, images are stored where they are acquired then, each night they are compressed using a lossy standard image compression algorithm (JPEG) and stored on a specialized IR data server. Between shots, acquisition systems act as servers and physicists can read data using a dedicated analysis software. For post-analysis purposes, all compressed images are read from the IR data server using the same analysis software or for in-depth analysis, physicists can use the Matlab interface we have developed. (authors)

  17. Plasma biasing by fast particles generation in front of CASTOR and TORE SUPRA tokamak LH grills

    International Nuclear Information System (INIS)

    Petrzilka, V.; Jakubka, K.; Klima, R.

    1999-01-01

    Computation results are presented concerning the electron acceleration by the LH wave alone, which are necessary for determining the value of the effective ponderomotive potential W. One set of selected parameters is representative for large tokamaks like Tore Supra and JET; the other set is representative for the small CASTOR tokamak. To estimate the value of W, the test-particle model was used for describing the electron acceleration. Then, by using the two-fluid model, profiles of U and Ε z are presented. Further, by using the corresponding value of W in the Particle-in-Cell model for the simulations of the plasma vortex in front of the LH grill, the effects are explored of the electrostatic fields Ε r , Ε θ and Ε z , on the following processes: 1. particle acceleration in front of LH grills by rf waves - it is demonstrated that in addition to electron acceleration, the charge-separation electrostatic field Ε z also accelerates ions to energies of several keV; 2. effects of plasma sources on the flow of particles from the narrow layer in front of the LH grill mouth - here it is shown that ionization alone is not sufficient for creating the experimentally observed plasma densities in front of LH grills

  18. Experience feedback from high heat flux component manufacturing for Tore Supra

    International Nuclear Information System (INIS)

    Schlosser, J.; Durocher, A.; Huber, T.; Garin, P.; Schedler, B.; Agarici, G.

    2001-01-01

    Tore Supra is involved in flat tile carbon armoured plasma facing components (PFCs) since 1985. In 1997, a third generation of components, based on the original concept developed with Plansee Company, called active metal casting (AMC[reg]), has been launched. Since 1998, 660 elementary components for the toroidal pump limiter (TPL) are in production. The route of the manufacture is rather complex and many controls were requested all along the fabrication to insure a high reliability of the elements. One of the main controls is the final infrared (IR) test allowing to determine the quality of the bonding between the carbon fibre composite (CFC) tiles and the heat sink made of copper-chromium-zirconium alloy (CuCrZr). Although results for the first batch of elements were as expected (less than 5% rejected at the final test), unexpected defects appeared with the followings batches. Investigations on the fabrication processes underlined the importance of having a better heat treatment of the pieces in copper alloy (CuCrZr), however this was not sufficient to completely explain the observed defects

  19. Power exhaust and edge control in steady state Tore Supra plasma

    International Nuclear Information System (INIS)

    Mitteau, R.

    2002-01-01

    Tore Supra is operated since 2001 with a flat limiter which is designed for 10 MW/m 2 . The limiter is located in the bottom of the vacuum vessel. It was only partial in 2001, but it is now fully toroidal without poloidal leading edges. Part of the experimental campaign of 2001 was devoted to the physical as well as technological qualification of the limiter. For 4 MW injected, the limiter extracted 2.5 MW and heat flux densities reached 2.5 MW/m 2 . It is still modest compared to the design value, but nonetheless enables a comparison to the modelling as surface temperature increased locally to 400 deg C. Thermal steady state is reached in 5-8 seconds. The values of heat flux and the deposition pattern are in very good accordance with design simulations. The heat flux pattern is a combination of parallel and perpendicular flow components which are roughly of equal magnitude. Insights on the heat flux deposition pattern as well as on the tiles behaviour are given. Operation with such a large size high heat flux component sets renewed emphasis on issues such as feed back systems, active security, cooling parameter and in situ assessment of the elements. They are dealt with in the paper. (author)

  20. Lower hybrid wave coupling in Tore Supra through multi junction launchers

    International Nuclear Information System (INIS)

    Litaudon, X.; Berger By, G.; Bibet, P.; Bizarro, J.P.; Capitain, J.J.; Carrasco, J.; Goniche, M.; Hoang, G.T.; Kupfer, K.; Magne, R.; Moreau, D.; Peysson, Y.; Rax, J.M.; Rey, G.; Rigaud, D.; Tonon, G.

    1992-01-01

    The TORE SUPRA Lower Hybrid Current Drive experiments (8 MW/3.7GHz) use large phased waveguide arrays, to couple the waves to the plasma. These launchers are based on the multi junction principle. Extensive coupling measurements have been performed in order to study the Radio-Frequency (RF) characteristics of the plasma loaded antennae and are reported. Measurements of the plasma scattering coefficients of the antennae show good agreement with those obtained from the linear coupling theory (SWAN code). Global reflection coefficients of a few percents have been measured in a large range of edge plasma densities or antenna positions, and up to a maximum injected RF power density of 45MW/m 2 . When the plasma is pushed against the inner wall of the chamber, the reflection coefficient was found to remain low up to distances of the order of 10 cm. The coupling measurements allow us to deduce the experimental power spectra radiated by the antennae when all their modules are fed simultaneously with variable phases. An assessment of the multi junction launcher as a viable antenna for high power transmission with good coupling characteristics and spectrum control is thus made

  1. Cross-field dynamics of the homogenization of the pellet deposited material in Tore Supra

    International Nuclear Information System (INIS)

    Sakamoto, R.; Pégourié, B.; Clairet, F.; Géraud, A.; Gil, C.; Hacquin, S.; Köchl, F.

    2013-01-01

    For investigating the damping effect of low-order rational surfaces on the drift of pellet deposited plasmoids, a safety factor (q) profile scan experiment was performed in Tore Supra, on a series of discharges with identical temperature and density profiles. Fast time-resolved density measurements show that the position of the deposition peak does not move smoothly during the ablation/homogenization phase but changes step by step, each step being located close to an integer or half-integer q value. This behaviour is well reproduced by time-dependent simulations with the pellet ablation/deposition code HPI2, which takes into account the braking of the plasmoid drift by external currents flowing along field lines in the background plasma. The key feature of this damping mechanism is a modulation as a function of the local safety factor, the braking being more effective in the vicinity of simple rational q values. The overall agreement between measurements and code predictions for a significant range of edge safety factors is fully consistent with the fact that the limitation of the plasmoid polarization by parallel currents is the dominant damping process of the ∇B-induced drift in tokamaks. (paper)

  2. Evaluation of the growth of carbonaceous deposit in steady state Tore Supra using infrared thermography

    Science.gov (United States)

    Mitteau, R.; Guilhem, D.; Reichle, R.; Vallet, J. C.; Roche, H.; Buravand, Y.; Chantant, M.; Tsitrone, E.; Brosset, C.; Grosman, A.; Chappuis, P.

    2006-03-01

    Fusion devices with carbon as the main armour material are experiencing a growth in carbonaceous deposits at the surface of the plasma facing components. Tore Supra presents such deposits, and has specific features which influence their growth: long pulse operation and cooled walls. Deposits have a low thermal transfer to the cooled structure so that they appear as hot areas with the infrared imaging system looking at the elements surface temperature during plasma discharges. A 'degree of (carbon) deposit' on the toroidal pumped limiter is estimated by establishing the ratio between the apparent power on the limiter derived from the infrared measure and the actual one, deduced from a power balance analysis between the injected and the radiated power. This criterion is used to monitor the evolution of the deposit average thermal resistance. Successive shots have a similar 'degree of deposit', showing that the evaluation makes sense. Two years of data have been compiled (2003 and 2004), representing 3000 discharges (13 h of plasma, including 30 discharges longer than one minute). A three-fold increase in the 'degree of deposit' over six months is evidenced, following a limiter clean-up early in 2003. A comparison with calorimetric data produces a similar result, albeit less pronounced. Large steps in the degree of deposit are sometimes observed, usually correlated with identified events such as disruption, vessel opening, conditioning or plasma parameters change. It indicates that the deposit thermal resistance can change rapidly, although a systematic correlation with the above mentioned events could not be established.

  3. Study and impact of fast electrons diagnosed by electron cyclotron radiation on Tore-Supra tokamak

    International Nuclear Information System (INIS)

    Gomez, P.

    1999-12-01

    This thesis aims at characterizing the dynamics of fast electrons generated by the Landau absorption of the hybrid wave and studying their effects on electron cyclotron radiation. The different processes involved in the propagation and resonant absorption of the hybrid wave in plasmas are described. A method such as ray-tracing allows the characterization of the dynamics of heating but this method relies on the hypothesis of geometrical optics. Whenever absorption rate is low as it is in Tore-Supra, the hybrid wave undergoes a series of successive reflections on the edge of the plasma before being completely absorbed. These reflections generate an electromagnetic chaos in which geometrical optics hypothesis are no longer valid. A statistical treatment of the Fokker-Planck equation allows the calculation of the mean distribution function of electrons in the plasma submitted to hybrid wave. The electron cyclotron radiation is then deduced and by assuming that plasma behaves like a black body, a theoretical radiative temperature is calculated. The confrontation of this theoretical temperature profile with experimental values allows the validation of this modeling and the estimation of the effects of fast electrons on temperature measurements. (A.C.)

  4. Deuterium in-vessel retention characterisation through the use of particle balance on Tore Supra

    International Nuclear Information System (INIS)

    Bucalossi, J.; Brosset, C.; Pegourie, B.; Tsitrone, E.; Dufour, E.; Eckedahl, A.; Geraud, A.; Goniche, M.; Gunn, J.; Loarer, T.; Monier-Garbet, P.; Vallet, J.C.; Vartanian, S.

    2007-01-01

    Fuel retention inside plasma facing components will be a crucial issue not only in fusion reactors of the future, but also in ITER. The estimation of the fraction of the fuel which remains trapped inside the vessel is quite a difficult task. Particle balance analysis provides information for the whole vacuum chamber as a function of time and can be use to monitor the tritium in-vessel retention in real-time. On Tore Supra with a careful choice and position of pressure sensors, proper calibration procedures, the accuracy of the balance is around 10%. Particle balance analysis have been performed on many long pulse discharges and deuterium in-vessel retention has been found to be a constant around 5 x 10 20 D/s after several minutes of plasma. The evolution of the retention rate with plasma parameters indicates that deuterium bulk implantation and diffusion could dominate codeposition with carbon atoms. Particle balance is a powerful tool that should be implemented in ITER

  5. Coupling between particle and heat transport during power modulation experiments in Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Zou, X.L.; Giruzzi, G.; Artaud, J.F.; Bouquey, F.; Bremond, S.; Clary, J.; Darbos, C.; Eury, S.P.; Lennholm, M.; Magne, R.; Segui, J.L

    2004-07-01

    Power modulations are a powerful tool often used to investigate heat transport processes in tokamaks. In some situations, this could also be an interesting method for the investigation of the particle transport due to the anomalous pinch. Low frequency ({approx} 1 Hz) power modulation experiments, using both electron cyclotron resonance heating (ECRH) and ion cyclotron resonance heating (ICRH), have been performed in the Tore Supra tokamak. Strong coupling has been observed between the temperature and density modulations during the low frequency ECRH and ICRH modulation experiments. It has been shown that mechanisms as outgassing, Ware pinch effect, curvature driven pinch are not likely to be responsible for this density modulation. Because of its dependence on temperature or temperature gradient, the thermodiffusion is a serious candidate to be the driving source for this density modulation. This analysis shows that low frequency power modulation experiments have a great potential for the investigation of the anomalous particle pinch in tokamaks. Future plans will include the use of more precise density profile measurements using X-mode reflectometry.

  6. Plasma-surface interactions with ICRF antennas and lower hybrid grills in Tore Supra

    International Nuclear Information System (INIS)

    Harris, J.H.; Hutter, T.; Hogan, J.T.; Basiuk, V.; Beaumont, B.; Becoulet, A.; Bremond, S.; Carter, M.D.; Goniche, M.; Goulding, R.H.; Guilhem, D.; Haste, G.R.; Hoffman, D.J.; Litaudon, X.; Nguyen, F.

    1997-01-01

    The edge plasma interactions of the actively cooled radio-frequency heating launchers in Tore Supra ion-cyclotron range of frequencies (ICRF) antennas and lower-hybrid (LH) grills are studied using infrared video imaging. On the two-strap ICRF antennas, operated in fast-wave electron heating or current drive mode, hot spots with temperatures of 500-900 C are observed by the end of 2 s power pulses of 2 MW per antenna. The steady-state temperature distribution is determined principally by the relative phase of the two antenna straps: dipole (heating) phasing results in significantly less antenna heating than does 90 (current drive) phasing. Transient heat fluxes of 1-20 MW/m 2 are measured on the lateral protection bumpers at ICRF turn-on; these fluxes are primarily a function of plasma and radio frequency (rf) control. The remarkable feature of the lower hybrid edge interaction is the production of beams of heat flux in front of the grills; these beams propagate along the helical magnetic field lines and can deliver fluxes of 5-10 MW/m 2 over areas of several cm 2 to plasma-facing components. Both the ICRF and LH phenomena appear to result from the acceleration of particles by the near fields of the launchers. Modeling of the heat flux deposition on components and its relation to sputtering processes is presented. (orig.)

  7. Particle exhaust of helium plasmas with actively cooled outboard pump limiter on Tore Supra

    International Nuclear Information System (INIS)

    Uckan, T.; Mioduszewski, P.K.; Loarer, T.; Chatelier, M.; Guilhem, D.; Lutz, T.; Nygren, R.E.; Mahdavi, M.A.

    1995-08-01

    The superconducting tokamak Tore Supra was designed for long-pulse (30-s) high input power operation. Here observations on the particle-handling characteristics of the actively cooled modular outboard pump limiter (OPL) are presented for helium discharges. The important experimental result was that a modest pumping speed (1 m 3 /s) of the OPL turbomolecular pump (TMP) provided background helium exhaust. This result came about due to a well-conditioned vessel wall with helium discharges that caused no wall outgasing. The particle accountability in these helium discharges was excellent, and the well-conditioned wall did not play a significant role in the particle balance. The helium density control, 25% density drop with OPL exhaust efficiency of ∼1%, was possible with TMP although this may not be the case with reactive gases such as deuterium. The observed quadratic increase of the OPL neutral pressure with helium density was consistent with an improvement of the particle control with increasing plasma density

  8. Assessing braze quality in the actively cooled Tore Supra Phase III outboard pump limiter

    International Nuclear Information System (INIS)

    Nygren, R.E.; Lutz, T.L.; Miller, J.D.; McGrath, R.; Dale, G.

    1994-01-01

    The quality of brazing of pyrolytic graphite armor brazed to copper tubes in Tore Supra's Phase III Outboard Pump Limiter was assessed through pre-service qualification testing of individual copper/tile assemblies. The evaluation used non-destructive, hot water transient heating tests performed in the high-temperature, high-pressure flow loop at Sandia's Plasma Materials Test Facility. Surface temperatures of tiles were monitored with an infrared camera as water at 120 degrees C at about 2.07 MPa (300 psi) passed through a tube assembly initially at 30 degrees C. For tiles with braze voids or cracks, the surface temperatures tagged behind those of adjacent well-bonded tiles. Temperature tags were correlated with flaw sizes observed during repairs based upon a detailed 2-D heat transfer analyses. open-quotes Badclose quotes tiles, i.e., temperature tags of 10-20 degrees C depending upon tile's size, were easy to detect and, when removed, revealed braze voids of roughly 50% of the joint area. Eleven of the 14 tubes were rebrazed after bad tiles were detected and removed. Three tubes were rebrazed twice

  9. Effects of ionizing scrape-off layers on local recycling in Tore Supra pump limiter experiments

    International Nuclear Information System (INIS)

    Chatelier, M.; Loarer, T.

    1992-01-01

    A series of ohmic discharges with active pumping in the Tore Supra outboard pump limiter has been analyzed with the DEGAS neutrals transport code and an analytic scrape-off layer (SOL) plasma model. Pumping speed and plenum pressure measurements indicated 5-10 torr.L/s throughput with only modest effects on density. A model is developed in which large exhaust fluxes, with little attendant effect on core plasma density, are explained in terms of SOL ionization of recycled and wall-desorbed neutrals. Particle balance with active pumping and constant line density requires that the wall return flux exceed the incident flux by approximately the pump throughput in the absence of external fueling. The radial profile of the H + source rate from ionization and dissociation of wall-desorbed molecules is seen to peak very near the radial position of the limiter throat. Consequently, a strong recycling vortex is created in the region of the limiter, with the ion flux amplified by factors of 2 at the outer limiter surfaces and > 3 within the limiter throat. The calculations indicate that less than 30% of the pump throughput is due to first-generation ions from the core efflux, with the balance from local recycling in the strongly ionizing SOL

  10. X mode reflectometry for edge density profile measurements on Tore Supra

    International Nuclear Information System (INIS)

    Clairet, F.; Bottereau, C.; Chareau, J.M.; Paume, M.; Sabot, R.

    1999-01-01

    X mode heterodyne reflectometry associated with fast sweep capabilities demonstrates very precise measurement on Tore Supra and a high sensitivity (∼10 17 m -3 ) to density variations. Very good agreement with Thomson scattering measurement is observed. Fluctuations of the radial positions of the profile are no more than ± 0.5 cm. However, edge magnetic field ripple can be a concern since it is not easy to stand precisely for the wave trajectory into the plasma and for the toroidal position of the cutoff layer; nevertheless if the error can be estimated to be less than than 3 cm in the position of the whole profile, addition work is needed combining 3-D ray tracing and different antenna systems. Additional LH heating generates an ECE noise in the same frequency range of the reflectometer and is detected. This emission throughout the plasma is fortunately stopped by the upper X mode cutoff and is also reabsorbed by the electron cyclotron resonance. But at the very edge, due to a misalignment of the antenna to the plasma magnetic field and the low optical thickness of the plasma, the first cutoff frequency, i.e. the profile initialization, may be determined less precisely. (authors)

  11. Near infrared thermography by CCD cameras and application to first wall components of Tore Supra tokamak; Thermographie proche infrarouge par cameras CCD et application aux composants de premiere paroi du tokamak Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, F.

    1996-06-07

    In the Tokamak TORE-SUPRA, the plasma facing components absorbs and evacuate (active cooling) high power fluxes (up to 10 MW/m{sup 2}). Their thermal behavior study is essential for the success of controlled thermonuclear fusion line. The first part is devoted to the study of power deposition on the TORE-SUPRA actively cooled limiters. A model of power deposition on one of the limiters is developed. It takes into account the magnetic topology and a description of the plasma edge. The model is validated with experimental calorimetric data obtained during a series of shots. This will allow to compare the surface temperature measurements with the predicted ones. The main purpose of this thesis was to evaluate and develop a new temperature measurement system. It works in the near infrared range (890 nm) and is designed to complete the existing thermographic diagnostic of TORE-SUPRA. By using the radiation laws (for a blackbody and the plasma) and the laboratory calibration one can estimate the surface temperature of the observed object. We evaluate the performances and limits of such a device in the harsh conditions encountered in a Tokamak environment. On the one hand, in a quasi ideal situation, this analysis shows that the range of measurements is 600 deg. C to 2500 deg. C. On the other hand, when one takes into account of the plasma radiation (with an averaged central plasma density of 6.10{sup 19} m{sup -3}), we find that the minimum surface temperature rise to 900 deg. C instead of 700 deg. C. In the near future, according to the development of IR-CCD cameras working in the near infrared range up to 2 micrometers, we will be able to keep the good spatial resolution with an improved lower limit for the temperature down to 150 deg. C. The last section deals with a number of computer tools to process the images obtained from experiments on TORE-SUPRA. A pattern recognition application was developed to detect a complex plasma iso-intensity structure. 87 refs.

  12. Infrared surface temperature measurements for long pulse operation, and real time feedback control in Tore-Supra, an actively cooled Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Guilhem, D.; Adjeroud, B.; Balorin, C.; Buravand, Y.; Bertrand, B.; Bondil, J.L.; Desgranges, C.; Gauthier, E.; Lipa, M.; Messina, P.; Missirlian, M.; Mitteau, R.; Moulin, D.; Pocheau, C.; Portafaix, C.; Reichle, R.; Roche, H.; Saille, A.; Vallet, S

    2004-07-01

    Tore-Supra has a steady-state magnetic field using super-conducting magnets and water-cooled plasma facing components for high performances long pulse plasma discharges. When not actively cooled, plasma-facing components can only accumulate a limited amount of energy since the temperature increase continuously (T proportional to {radical}(t)) during the discharge until radiation cooling is equal to the incoming heat flux (T > 1800 K). Such an environment is found in most today Tokamaks. In the present paper we report the recent results of Tore-Supra, especially the design of the new generation of infrared endoscopes to measure the surface temperature of the plasma facing components. The Tore-Supra infrared thermography system is composed of 7 infrared endoscopes, this system is described in details in the paper, the new JET infrared thermography system is presented and some insights of the ITER set of visible/infrared endoscope is given. (authors)

  13. Infrared surface temperature measurements for long pulse operation, and real time feedback control in Tore-Supra, an actively cooled Tokamak

    International Nuclear Information System (INIS)

    Guilhem, D.; Adjeroud, B.; Balorin, C.; Buravand, Y.; Bertrand, B.; Bondil, J.L.; Desgranges, C.; Gauthier, E.; Lipa, M.; Messina, P.; Missirlian, M.; Mitteau, R.; Moulin, D.; Pocheau, C.; Portafaix, C.; Reichle, R.; Roche, H.; Saille, A.; Vallet, S.

    2004-01-01

    Tore-Supra has a steady-state magnetic field using super-conducting magnets and water-cooled plasma facing components for high performances long pulse plasma discharges. When not actively cooled, plasma-facing components can only accumulate a limited amount of energy since the temperature increase continuously (T proportional to √(t)) during the discharge until radiation cooling is equal to the incoming heat flux (T > 1800 K). Such an environment is found in most today Tokamaks. In the present paper we report the recent results of Tore-Supra, especially the design of the new generation of infrared endoscopes to measure the surface temperature of the plasma facing components. The Tore-Supra infrared thermography system is composed of 7 infrared endoscopes, this system is described in details in the paper, the new JET infrared thermography system is presented and some insights of the ITER set of visible/infrared endoscope is given. (authors)

  14. Role of the pump limiter throat-ergodic divertor effect on edge plasma

    International Nuclear Information System (INIS)

    Grosman, A.; Samain, A.; Ghendrih, P.; Capes, H.; Morera, J.P.

    1988-01-01

    A large part of the Tore Supra programme is devoted to plasma edge studies. Two types of such density control apparatus have been implemented, a set of pumps limiters and the ergodic divertor. The goal of the present paper is to investigate the effect of the pump limiter throat on pumping efficiency. We present also the possibilities of the ergodic divertor device to facilitate plasma pumping and power exhaust

  15. Experimental characterization and modelling of non-linear coupling of the lower hybrid current drive power on Tore Supra

    Science.gov (United States)

    Preynas, M.; Goniche, M.; Hillairet, J.; Litaudon, X.; Ekedahl, A.; Colas, L.

    2013-01-01

    To achieve steady-state operation on future fusion devices, in particular on ITER, the coupling of the lower hybrid wave must be optimized on a wide range of edge conditions. However, under some specific conditions, deleterious effects on the lower hybrid current drive (LHCD) coupling are sometimes observed on Tore Supra. In this way, dedicated LHCD experiments have been performed using the LHCD system of Tore Supra, composed of two different conceptual designs of launcher: the fully active multi-junction (FAM) and the new passive active multi-junction (PAM) antennas. A non-linear interaction between the electron density and the electric field has been characterized in a thin plasma layer in front of the two LHCD antennas. The resulting dependence of the power reflection coefficient (RC) with the LHCD power is not predicted by the standard linear theory of the LH wave coupling. A theoretical model is suggested to describe the non-linear wave-plasma interaction induced by the ponderomotive effect and implemented in a new full wave LHCD code, PICCOLO-2D (ponderomotive effect in a coupling code of lower hybrid wave-2D). The code self-consistently treats the wave propagation in the antenna vicinity and its interaction with the local edge plasma density. The simulation reproduces very well the occurrence of a non-linear behaviour in the coupling observed in the LHCD experiments. The important differences and trends between the FAM and the PAM antennas, especially a larger increase in RC for the FAM, are also reproduced by the PICCOLO-2D simulation. The working hypothesis of the contribution of the ponderomotive effect in the non-linear observations of LHCD coupling is therefore validated through this comprehensive modelling for the first time on the FAM and PAM antennas on Tore Supra.

  16. Experimental characterization and modelling of non-linear coupling of the lower hybrid current drive power on Tore Supra

    International Nuclear Information System (INIS)

    Preynas, M.; Goniche, M.; Hillairet, J.; Litaudon, X.; Ekedahl, A.; Colas, L.

    2013-01-01

    To achieve steady-state operation on future fusion devices, in particular on ITER, the coupling of the lower hybrid wave must be optimized on a wide range of edge conditions. However, under some specific conditions, deleterious effects on the lower hybrid current drive (LHCD) coupling are sometimes observed on Tore Supra. In this way, dedicated LHCD experiments have been performed using the LHCD system of Tore Supra, composed of two different conceptual designs of launcher: the fully active multi-junction (FAM) and the new passive active multi-junction (PAM) antennas. A non-linear interaction between the electron density and the electric field has been characterized in a thin plasma layer in front of the two LHCD antennas. The resulting dependence of the power reflection coefficient (RC) with the LHCD power is not predicted by the standard linear theory of the LH wave coupling. A theoretical model is suggested to describe the non-linear wave–plasma interaction induced by the ponderomotive effect and implemented in a new full wave LHCD code, PICCOLO-2D (ponderomotive effect in a coupling code of lower hybrid wave-2D). The code self-consistently treats the wave propagation in the antenna vicinity and its interaction with the local edge plasma density. The simulation reproduces very well the occurrence of a non-linear behaviour in the coupling observed in the LHCD experiments. The important differences and trends between the FAM and the PAM antennas, especially a larger increase in RC for the FAM, are also reproduced by the PICCOLO-2D simulation. The working hypothesis of the contribution of the ponderomotive effect in the non-linear observations of LHCD coupling is therefore validated through this comprehensive modelling for the first time on the FAM and PAM antennas on Tore Supra. (paper)

  17. Precision and resolution on Tore-Supra ECE electron temperature profile measurements

    International Nuclear Information System (INIS)

    Segui, J.L.; Molina, D.; Goniche, M.

    2003-01-01

    A 16-channel heterodyne radiometer, 2 GHz spaced, is used on Tore-Supra to measure the electron cyclotron emission in the frequency range 78-110 GHz for the O mode and 94 -126 GHz for the X mode. In the equatorial plane, a dual polarisation Gaussian optics lens antenna, with a perpendicular line of sight (with respect to the magnetic field), gives ECE measurements with very low refraction and Doppler effects. A separate O/X mode RF front-end allows the use of an IF electronic mode selector. This improves time stability calibration and gives the potentiality of simultaneous O/X mode measurements in the 94 -110 GHz RF band for polarisation studies. RF and IF filters reject the gyrotron frequency (118 GHz) in order to perform temperature measurements during ECRH plasmas. A precise absolute spectral calibration is performed outside the vacuum vessel by using a 600 deg. C black body, a digital signal averaging on the waveform generated by a mechanical chopper placed directly in front of it, and a simulation window without Fabry-Perot effects. The calibration precision leads to ECE temperature profiles which are very consistent with Thomson scattering measurements and guarantees a good stability of the ECE profiles for small changes on the magnetic field (absolute precision ± 6%, relative precision between channels ± 3%). Post-pulse data processing takes routinely into account the total magnetic field (B vacuum with ripple, B para , B dia , B pol , all with analytical formulations), the radial relativistic shift (analytical formulation is used), the refraction, not described in this paper, (cut-off detection with safety margin to avoid strong refraction), the nonthermal ECE spectra, not described in this paper, during LHCD (using an electron density threshold criterion). These previous analytical formulations are compatible with real time processing. Relativistic radial broadening simulations show that it is useful to fulfill 32 channels (1 GHz spaced). (authors)

  18. Precision and resolution on Tore-Supra ECE electron temperature profile measurements

    Energy Technology Data Exchange (ETDEWEB)

    Segui, J.L.; Molina, D.; Goniche, M. [Association EURATOM -CEA, CEA/DSM/DRFC CEA-Cadarache, 13108 St Paul-lez-Durance (France)

    2003-07-01

    A 16-channel heterodyne radiometer, 2 GHz spaced, is used on Tore-Supra to measure the electron cyclotron emission in the frequency range 78-110 GHz for the O mode and 94 -126 GHz for the X mode. In the equatorial plane, a dual polarisation Gaussian optics lens antenna, with a perpendicular line of sight (with respect to the magnetic field), gives ECE measurements with very low refraction and Doppler effects. A separate O/X mode RF front-end allows the use of an IF electronic mode selector. This improves time stability calibration and gives the potentiality of simultaneous O/X mode measurements in the 94 -110 GHz RF band for polarisation studies. RF and IF filters reject the gyrotron frequency (118 GHz) in order to perform temperature measurements during ECRH plasmas. A precise absolute spectral calibration is performed outside the vacuum vessel by using a 600 deg. C black body, a digital signal averaging on the waveform generated by a mechanical chopper placed directly in front of it, and a simulation window without Fabry-Perot effects. The calibration precision leads to ECE temperature profiles which are very consistent with Thomson scattering measurements and guarantees a good stability of the ECE profiles for small changes on the magnetic field (absolute precision {+-} 6%, relative precision between channels {+-} 3%). Post-pulse data processing takes routinely into account the total magnetic field (B{sub vacuum} with ripple, B{sub para}, B{sub dia}, B{sub pol}, all with analytical formulations), the radial relativistic shift (analytical formulation is used), the refraction, not described in this paper, (cut-off detection with safety margin to avoid strong refraction), the nonthermal ECE spectra, not described in this paper, during LHCD (using an electron density threshold criterion). These previous analytical formulations are compatible with real time processing. Relativistic radial broadening simulations show that it is useful to fulfill 32 channels (1 GHz

  19. Plasma enhanced RF power deposition on ICRF antennas in Tore Supra

    International Nuclear Information System (INIS)

    Goulding, R.H.; Harris, J.H.; Carter, M.D.; Hoffman, D.J.; Hogan, J.T.; Ryan, P.M.; Beaumont, B.; Bremond, S.; Hutter, T.

    1997-01-01

    The dual-strap Tore Supra ICRF antennas have been very successful in coupling high power fluxes > 16 MW/m2 to the plasma. In many cases it has been found that the power is limited not by the voltages and currents that can be sustained on antenna components, but rather by localized increases in antenna surface temperatures which are correlated with increased impurity levels. Hot spots have been observed using an IR imaging system with peak temperatures as high as 1,100 C after 2 s, and as little as 1.5 MW power coupled from a single launcher. The maximum temperature observed is highly dependent on antenna phasing, and is lowest with dipole (π) phasing of the relative antenna currents. Both toroidal and poloidal asymmetries in hot spot distribution have been observed, and interestingly, the toroidal asymmetry has been found to vary when the phase is changed from +π/2 to -π/2. Significant differences in the temperature profiles have been seen on the two types of Faraday shield in use, which appears to be related to the fact that one type has a recessed center septum between straps while the other does not. In some cases, the peak temperature has been observed to increase as the antenna/plasma gap is increased, while the peak remains in the same location. This behavior suggests that voltages generated by currents flowing in the Faraday shield structure itself may play a role in generating potentials responsible for the hot spots, in addition to rf fields in the plasma. In this paper data on antenna surface heating and loading data as a function of plasma density, antenna/plasma gap, and phasing will be presented. Calculations from the RANT3D electromagnetic code together with bench measurements of electric fields near the antenna surface will also be shown

  20. Plasma-surface interactions with ICRF antennas and lower hybrid grills in Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Harris, J.H. [Oak Ridge National Lab., TN (United States); Hutter, T. [Association Euratom-CEA, Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Hogan, J.T. [Oak Ridge National Lab., TN (United States)] [and others

    1996-10-01

    The edge plasma interactions of the actively cooled radio-frequency heating launchers in Tore Supra- ion-cyclotron range-of-frequencies (ICRF) antennas and lower-hybrid (LH) grills-are studied using infrared video imaging. On the two-strap ICRF antennas, operated in fast-wave electron heating or current drive mode, hot spots with temperatures of 500-900{degrees} C are observed by the end of 2-s power pulses of 2 MW per antenna. The distribution and maximum values of temperature are determined principally by the relative phase of the two antenna straps: dipole (heating) phasing results in significantly less antenna heating than does 90` (current drive) phasing. Transient heat fluxes of 1-20 MW/m{sup 2} are measured on the lateral protection bumpers at ICRF turn-on; these fluxes are primarily a function of plasma and radio frequency (rf) control, and are not simply correlated with the strap phasing or the final surface temperature distributions. The remarkable feature of the lower hybrid edge interaction is the production of beams of heat flux in front of the grills; these beams propagate along the helical magnetic field lines and can deliver fluxes of 5-10 MW/m{sup 2} over areas of several cm{sup 2} to plasma-facing components such as the grill or antenna lateral bumpers. Both the ICRF and LH phenomena appear to result from the acceleration of particles by the near fields of the launchers. Modeling of the heat flux deposition on components and its relation to sputtering processes is presented, and possibilities for controlling these interactions are discussed.

  1. Spectral broadening measurement of the lower hybrid waves during long pulse operation in Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Berger-By, G.; Decampy, J.; Goniche, M.; Ekedahl, A.; Delpech, L.; Leroux, F. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Antar, G. Y. [American University of Beirut, Riad el-Solh, Beirut 1107-2020 (Lebanon); Collaboration: Tore Supra Team

    2014-02-12

    On many tokamaks (C-Mod, EAST, FTU, JET, HT-7, TS), a decrease in current drive efficiency of the Lower Hybrid (LH) waves is observed in high electron density plasmas. The cause of this behaviour is believed to be: Parametric Instabilities (PI) and Scattering from Density Fluctuations (SDF). For the ITER LH system, our knowledge must be improved to avoid such effects and to maintain the LH current drive efficiency at high density. The ITPA IOS group coordinates this effort [1] and all experimental data are essential to validate the numerical codes in progress. Usually the broadening of the LH wave frequency spectrum is measured by a probe located in the plasma edge. For this study, the frequency spectrum of a reflected power signal from the LH antenna was used. In addition, the spectrum measurements are compared with the density fluctuations observed on RF probes located at the antenna mouth. Several plasma currents (0.6 to 1.4 MA) and densities up to 5.2 × 10{sup 19} m−3 have been realised on Tore Supra (TS) long pulses and with high injected RF power, up to 5.4 MW-30s. This allowed using a spectrum analyser to make several measurements during the plasma pulse. The side lobe amplitude, shifted by 20-30MHz with respect to the main peak, grows with increasing density. Furthermore, for an increase of plasma current at the same density, the spectra broaden and become asymmetric. Some parametric dependencies are shown in this paper.

  2. Power balance for impurity seeded ergodic divertor discharges in Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Reichle, R.; Vallet, J.C.; Basiuk, V.; Chantant, M.; Giannella, R.; Guirlet, R.; Mitteau, R

    1999-10-15

    The main emphasis of the present contribution is the search for independent indications concerning local radiation enhancement in the vicinity of target plates by the application of the power-balance analysis to impurity seeded discharges and the use of spatially resolved calorimetry. All methods confirm the existence of an important local radiation enhancement in front of target objects. Their torlly localised nature and the lack of short scale toroidal resolution of the bolometers cause an underestimate of the radiation. Observed corrective factors for radiative divertor discharges range between 1.1 and 1.6 depending on the density. the impurity seeded discharges show during the impurity injection a reduction of this factor which can be explained by the radiation distribution becoming toroidally more symmetric due to larger ionisation lengths. The consistency of the results seems to validate the assumption of a fall off length of the radiation of 40 cm as used for the radiation extrapolation from the outboard calorimetry. The localised extra radiation falling onto one individual neutralizer is about 1 kW. This should be compared with spectroscopic radiation measurements and modelling to see whether there is room for charge exchange neutrals to be important. (authors)

  3. Power balance for impurity seeded ergodic divertor discharges in Tore Supra

    International Nuclear Information System (INIS)

    Reichle, R.; Vallet, J.C.; Basiuk, V.; Chantant, M.; Giannella, R.; Guirlet, R.; Mitteau, R.

    1999-01-01

    The main emphasis of the present contribution is the search for independent indications concerning local radiation enhancement in the vicinity of target plates by the application of the power-balance analysis to impurity seeded discharges and the use of spatially resolved calorimetry. All methods confirm the existence of an important local radiation enhancement in front of target objects. Their toroidally localised nature and the lack of short scale toroidal resolution of the bolometers cause an underestimate of the radiation. Observed corrective factors for radiative divertor discharges range between 1.1 and 1.6 depending on the density. the impurity seeded discharges show during the impurity injection a reduction of this factor which can be explained by the radiation distribution becoming toroidally more symmetric due to larger ionisation lengths. The consistency of the results seems to validate the assumption of a fall off length of the radiation of 40 cm as used for the radiation extrapolation from the outboard calorimetry. The localised extra radiation falling onto one individual neutralizer is about 1 kW. This should be compared with spectroscopic radiation measurements and modelling to see whether there is room for charge exchange neutrals to be important. (authors)

  4. Identification and real time control of current profile in Tore-supra: algorithms and simulation; Identification et controle en temps reel du profil de courant dans Tore Supra: algorithmes et simulations

    Energy Technology Data Exchange (ETDEWEB)

    Houy, P

    1999-10-15

    The aim of this work is to propose a real-time control of the current profile in order to achieve reproducible operating modes with improved energetic confinement in tokamaks. The determination of the profile is based on measurements given by interferometry and polarimetry diagnostics. Different ways to evaluate and improve the accuracy of these measurements are exposed. The position and the shape of a plasma are controlled by the poloidal system that forces them to cope with standard values. Gas or neutral ions or ice pellet or extra power injection are technical means used to control other plasma parameters. These controls are performed by servo-controlled loops. The poloidal system of Tore-supra is presented. The main obstacle to a reliable determination of the current profile is the fact that slightly different Faraday angles lead to very different profiles. The direct identification method that is exposed in this work, gives the profile that minimizes the square of the margin between measured and computed values. The different algorithms proposed to control current profiles on Tore-supra have been validated by using a plasma simulation. The code Cronos that solves the resistive diffusion equation of current has been used. (A.C.)

  5. Results of water corrosion in static cell tests representing multi-metal assemblies in the hydraulic circuits of Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Lipa, M.; Blanchet, J. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Cellier, F. [Framatome, Centre Technique, 71 - Saint Marcel (France)

    2007-07-01

    Full text of publication follows: Tore supra (TS) has used from the beginning of operation in 1989 actively cooled plasma facing components. Since the operation and baking temperature of all in vessel components has been defined to be up to 230 deg. C at 40 bars, a special water chemistry of the cooling water plant was suggested in order to avoid eventual water leaks due to corrosion (general corrosion, galvanic corrosion, stress corrosion, etc.) at relative high temperatures and pressures in tubes, pipes, bellows, water boxes, coils, etc. From the beginning of TS operation, in vessel components (e.g. wall protection panels, limiters, ergodic divertor coils, neutralisers and diagnostics) represented a unique combination of metals in the hydraulic circuit mainly such as stainless steel, Inconel, CuCrZr, Nickel and Copper. These different materials were joined together by welding (St to St, Inconel to Inconel, CuCrZr to CuCrZr and CuCrZr to St-St via a Ni sleeve adapter), brazing (St-St to Cu and Cu-LSTP), friction (CuCrZr and Cu to St-St), explosion (CuCrZr to St-St) and memory metal junction (Cryo-fit to Cu - only test sample). Following experiences obtained with steam generator tubes of nuclear power plants, a cooling water quality of AVT (all volatile treatment) has been defined based on demineralized water with adjustment of the pH value to about 9.0/ 7.0 (25 deg. C/ 200 deg. C) by addiction of ammoniac, and hydrazine in order to absorb oxygen dissolved in water. At that time, a simplified water corrosion test program has been performed using static (no circulation) test cell samples made of above mentioned TS metal combinations. All test cell samples, prepared and filled with AVT water, were performed at 280 deg. C and 65 bars in an autoclave during 3000 hours. The test cell water temperature has been chosen to be sufficient above the TS component working temperature, in order to accelerate an eventual corrosion process. Generally all above mentioned metal

  6. Results of water corrosion in static cell tests representing multi-metal assemblies in the hydraulic circuits of Tore Supra

    International Nuclear Information System (INIS)

    Lipa, M.; Blanchet, J.

    2007-01-01

    Full text of publication follows: Tore supra (TS) has used from the beginning of operation in 1989 actively cooled plasma facing components. Since the operation and baking temperature of all in vessel components has been defined to be up to 230 deg. C at 40 bars, a special water chemistry of the cooling water plant was suggested in order to avoid eventual water leaks due to corrosion (general corrosion, galvanic corrosion, stress corrosion, etc.) at relative high temperatures and pressures in tubes, pipes, bellows, water boxes, coils, etc. From the beginning of TS operation, in vessel components (e.g. wall protection panels, limiters, ergodic divertor coils, neutralisers and diagnostics) represented a unique combination of metals in the hydraulic circuit mainly such as stainless steel, Inconel, CuCrZr, Nickel and Copper. These different materials were joined together by welding (St to St, Inconel to Inconel, CuCrZr to CuCrZr and CuCrZr to St-St via a Ni sleeve adapter), brazing (St-St to Cu and Cu-LSTP), friction (CuCrZr and Cu to St-St), explosion (CuCrZr to St-St) and memory metal junction (Cryo-fit to Cu - only test sample). Following experiences obtained with steam generator tubes of nuclear power plants, a cooling water quality of AVT (all volatile treatment) has been defined based on demineralized water with adjustment of the pH value to about 9.0/ 7.0 (25 deg. C/ 200 deg. C) by addiction of ammoniac, and hydrazine in order to absorb oxygen dissolved in water. At that time, a simplified water corrosion test program has been performed using static (no circulation) test cell samples made of above mentioned TS metal combinations. All test cell samples, prepared and filled with AVT water, were performed at 280 deg. C and 65 bars in an autoclave during 3000 hours. The test cell water temperature has been chosen to be sufficient above the TS component working temperature, in order to accelerate an eventual corrosion process. Generally all above mentioned metal

  7. Shielding study of a fusion machine. Elaboration of a global shielding calculation scheme for the Tokamak tore Supra

    International Nuclear Information System (INIS)

    Diop, C.M'B.

    1984-01-01

    This thesis presents a global shielding calculation scheme for neutron and gamma rays arising from the Tokamak TORE SUPRA fusion device, in which a deuterium plasma is used. To study the shield parameters we have elabored a important chaining of neutron and gamma transport codes, TRIPOLI, ANISN, MERCURE 4, allowing to evaluate the radial and skyshine components of the dose rate behind the concrete shield. The study of thermonuclear neutron activation is fundamental to define a tokamak exploitation strategy. For this, two formalisme have been developed. They are based on a modelization of the activation reaction rates according to TRIPOLI, ANISN, and MERCURE 4 codes capabilities. The first one calculates, in one dimensional geometry, the desactivation gamma dose rate inside the vacuum chamber. The second one is a tridimensional model which determines the spatial variation of the gamma dose rate in the machine room. The problem of the existence of runaway electrons and associated secondaries radiations, bremsstrahlung gamma rays particularly, is approched. The results which are presented have contributed to define the parameters of the concrete shield and a strategy for TORE SUPRA Tokamak exploitation [fr

  8. Resuspension of carbon dust collected in Tore Supra and exposed to turbulent airflow: Controlled experiments and comparison with model

    Energy Technology Data Exchange (ETDEWEB)

    Peillon, S., E-mail: samuel.peillon@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSN-RES/SCA/LPMA, Saclay, Gif-sur-Yvette 91192 (France); Roynette, A. [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSN-RES/SCA/LPMA, Saclay, Gif-sur-Yvette 91192 (France); Grisolia, C. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Gensdarmes, F. [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSN-RES/SCA/LPMA, Saclay, Gif-sur-Yvette 91192 (France)

    2014-11-15

    Highlights: • Mobilization of dust is a key issue for the safety assessment of fusion reactors. • Carbon dust has been collected on the plasma facing components of Tore Supra. • Samples exhibit bimodal particle size distributions. • Samples have been exposed to turbulent airflows for dust resuspension studies. • A comparison with the so-called Rock’n roll resuspension model is proposed. - Abstract: This work presents the results of experiments conducted with carbon microparticles collected in the tokamak Tore Supra in order to characterize their resuspension behaviour from a stainless-steel substrate when exposed to turbulent airflow. Experiments were conducted in a wind tunnel with controlled velocity profiles and monitored environmental conditions. A consequent amount of dust has been collected in the vessel of the tokamak and a bimodal particle size distribution of samples is first demonstrated. Comparison with resuspension of alumina powders with equivalent particle size distributions under turbulent airflow is also discussed. Results for both carbon and alumina microparticles are then compared to a theoretical resuspension model. Data reveal that exposing multilayer deposits with bimodal particle size distributions to low-speed flows (i.e. 3–10 m/s) induces a significant reduction of the mobilized fractions compared to what was predicted by the model. In addition, results helped to highlight some limitations in the model to physically describe changes in the adhesive strength that can occur with a polydisperse deposit.

  9. The control of plasma density profile in Tore Supra. Comparison of different fueling techniques; Controle du profil de densite dans le plasma de Tore Supra. Comparaison de differentes methodes d'alimentation en particules

    Energy Technology Data Exchange (ETDEWEB)

    Commaux, N

    2007-09-15

    The behaviour of a reactor-class plasma when fuelled using the existing techniques (gas puffing, supersonic molecular beam injection and pellet injection) is still very difficult to foresee. The present work has been initiated on Tore Supra in order to extrapolate the consequences of the different fuelling systems on ITER. Two main topics have been studied: the comparison of the plasma behaviour when fuelled using the different techniques at high Greenwald density fractions and the study of the homogenization following a pellet injection (main fuelling technique for ITER burning plasmas). The experiments at high Greenwald density fractions performed on Tore Supra showed that the plasma behaviour is very dependent on the fuelling method. The plasma energy confinement is following the scaling laws determined at low density when fuelled using pellet injection. which is better than for gas puffing and SMBI. both inducing a significant confinement loss. This behaviour is nor related to a transport modification: the ratio between effective diffusion and convection is similar to the pellet case. The difference between these shots is related only to the position of the matter source (at the edge for gas and close to the center for pellets). The study concerning the homogenization phenomena following a pellet injection aims mainly to study the {nabla}B-drift effect that expels the mater deposited by a pellet toward the low field side. A new phenomenon. which appears to be particularly important for the {nabla}B-drift during low field side injections. was then discovered: the influence of magnetic surfaces with an integer-valued safety factor (q). When the mater drifting toward low field side crosses an integer q surface. it experiences an important braking effect which stops the drift motion. It implies that the pellet material is mainly deposited on the last integer q surface crossed by the pellet during its injection. This study allows also to determine that the {nabla

  10. Aqueous corrosion in static capsule tests representing multi-metal assemblies in the hydraulic circuit of Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Lipa, M. [Association Euratom-CEA, CEA/DSM/DRFC, Centre de Cadarache, 13108 Saint-Paul-Lez-Durance (France)], E-mail: manfred.lipa@cea.fr; Blanchet, J.; Feron, D. [CEA/DEN/SCCME, Centre de Saclay, 91191 Gif sur Yvette (France); Cellier, F. [AREVA ANP, Centre Technique, 71380 Saint Marcel (France)

    2008-12-15

    Tore supra (TS) in vessel components represent a unique combination of metals in the hydraulic circuit. Different materials, e.g. stainless steel, copper alloys, nickel, etc., were joined together by fusion welding, brazing and friction. Since the operation and baking temperature of all in vessel components has been defined to be set at 230 deg. C/40 bars a special water chemistry of the cooling water loop was suggested in order to prevent eventual water leaks due to corrosion at relative high temperatures and pressures in tubes, bellows, coils and coolant plant ancillary equipments. Following experiences with water chemistry in Pressurised Water Reactors, an all volatile chemical treatment (AVT) has been defined for the cooling water quality of TS. Since then, a simplified static (no fluid circulation) corrosion test program at relatively high temperature and pressure has been performed using capsule-type samples made of above mentioned multi-metal assemblies.

  11. High heat flux components in fusion devices: from nowadays experience in Tore Supra towards the ITER challenge

    International Nuclear Information System (INIS)

    Grosman, A.; Bayetti, P.; Chappuis, P.; Cordier, J.J.; Durocher, A.; Escourbiac, F.; Guilhem, D.; Lipa, M.; Marbach, G.; Mitteau, R.; Schlosser, J.

    2003-01-01

    A pioneering activity has been developed by CEA and the European industry in the field of actively cooled high heat flux plasma facing components in Tore Supra operation, which is today culminating with the routine operation of an actively cooled toroidal pumped limiter (TPL) capable to sustain up to 10 MW.m -2 of nominal convected heat flux. This success is the result of a long lead development and industrialization program (about 10 years) marked out with a number of technical and managerial challenges that were taken up and has allowed us to build up an unique experience feedback database. This is illustrated in this paper with the specific example of the development of high heat flux CFC-on-CuCrZr (carbon-carbon fibre composite on hardened copper alloy CuCrZr) component from design phase to tokamak operation. (authors)

  12. Detection of geodesic acoustic mode oscillations, using multiple signal classification analysis of Doppler backscattering signal on Tore Supra

    International Nuclear Information System (INIS)

    Vermare, L.; Hennequin, P.; Gürcan, Ö.D.

    2012-01-01

    This paper presents the first observation of geodesic acoustic modes (GAMs) on Tore Supra plasmas. Using the Doppler backscattering system, the oscillations of the plasma flow velocity, localized between r/a = 0.85 and r/a = 0.95, and with a frequency, typically around 10 kHz, have been observed at the plasma edge in numerous discharges. When the additional heating power is varied, the frequency is found to scale with C s /R. The MUltiple SIgnal Classification (MUSIC) algorithm is employed to access the temporal evolution of the perpendicular velocity of density fluctuations. The method is presented in some detail, and is validated and compared against standard methods, such as the conventional fast Fourier transform method, using a synthetic signal. It stands out as a powerful data analysis method to follow the Doppler frequency with a high temporal resolution, which is important in order to extract the dynamics of GAMs. (paper)

  13. Characterization of the up-down asymmetry of density fluctuations induced by a lower modular limiter in Tore Supra

    International Nuclear Information System (INIS)

    Fenzi, C.; Devynck, P.; Garbet, X.; Antar, G.; Capes, H.; Laviron, C.; Truc, A.; Gervais, F.; Hennequin, P.; Quemeneur, A.

    1999-01-01

    In magnetic fusion devices, the effect of plasma facing components on plasma turbulence is a key issue for several reasons. Firstly, the edge turbulence controls the power deposition on plasma facing components. Secondly, the possible influence of the edge parameters on the core fluctuations is a central question, since the core turbulent transport is responsible for the confinement degradation. It is in practice difficult to determine whether the plasma core influences the edge, or the opposite. We show here that spatial edge asymmetries of density fluctuations, and particularly up-down asymmetries, provide a powerful tool to investigate this problem. In TORE SUPRA, previous scaling analyses with various plasma parameters have emphasized that a very clear effect on the asymmetry level appears when the plasma leans on the lower modular limiter located close to the measurement chord. We present here recent measurement results concerning that specific case. They tend to show that the limiter configuration has some effect on the core turbulence. (authors)

  14. Flux consumption, current ramp-up and current diffusion in Tore Supra non-inductive Lower Hybrid scenarios

    International Nuclear Information System (INIS)

    Kazarian, F.; Litaudon, X.; Moreau, D.; Arslanbekov, R.; Hoang, G.T.; Joffrin, E.; Peysson, Y.; Allibert, J.P.; Ane, J.M.; Bremond, S.

    1995-01-01

    The main objective of the Lower Hybrid (LH) experiments performed on Tore Supra is to provide large flux savings for long pulse operation while controlling the plasma current density profile. This goal will be best achieved by applying LH wave directly during the current ramp-up phase. Experiments have been performed where a large fraction of the current is driven non-inductively during the ramp-up phase. A theoretical flux consumption scaling is presented and compared to experimental data. The time evolutions of the current density profiles are analysed with a new current diffusion code (CRONOS). In view to achieve fully non-inductive current drive discharges in a fast, systematic and reproducible way, experiments where the primary voltage is imposed have been carried out. In a complementary approach, an appropriate transformer flux feedback scheme has been also studied. (author) 6 refs.; 6 figs

  15. High heat flux components in fusion devices: from nowadays experience in Tore Supra towards the ITER challenge

    Energy Technology Data Exchange (ETDEWEB)

    Grosman, A.; Bayetti, P.; Chappuis, P.; Cordier, J.J.; Durocher, A.; Escourbiac, F.; Guilhem, D.; Lipa, M.; Marbach, G.; Mitteau, R.; Schlosser, J

    2003-07-01

    A pioneering activity has been developed by CEA and the European industry in the field of actively cooled high heat flux plasma facing components in Tore Supra operation, which is today culminating with the routine operation of an actively cooled toroidal pumped limiter (TPL) capable to sustain up to 10 MW.m{sup -2} of nominal convected heat flux. This success is the result of a long lead development and industrialization program (about 10 years) marked out with a number of technical and managerial challenges that were taken up and has allowed us to build up an unique experience feedback database. This is illustrated in this paper with the specific example of the development of high heat flux CFC-on-CuCrZr (carbon-carbon fibre composite on hardened copper alloy CuCrZr) component from design phase to tokamak operation. (authors)

  16. Evident anomalous inward particle pinch in full non-inductive plasmas driven by lower hybrid waves on Tore Supra

    International Nuclear Information System (INIS)

    Hoang, G.T.; Bourdelle, C.; Pegourie, B.; Artaud, J.F.; Bucalossi, J.; Clairet, F.; Fenzi-Bonizec, C.; Garbet, X.; Gil, C.; Guirlet, R.; Imbeaux, F.; Lasalle, J.; Loarer, T.; Lowry, C.; Schunke, B.; Travere, J.M.; Tsitrone, E.

    2003-01-01

    These slides present some characteristics concerning peaked density profile observed in Tore-Supra. It appears that density profile remains peaked for more than 3 minutes in fully LHCD (lower hybrid current drive) discharges. The absence of toroidal electric field and the fact that the ware pinch has vanished across the entire plasma show that toroidal electric field and ware pinch are not the cause of the peaked profile. It is shown that peaked profile is linked to transport properties and can only be explained by a particle pinch velocity 2 orders of magnitude above the neoclassical pinch. It is also shown that the radial profile is in agreement with Isitchenko's formula. (A.C.)

  17. Particle flux and temperature dependence of carbon impurity production from an inertially-cooled limiter in tore supra

    International Nuclear Information System (INIS)

    DeMichelis, C.; Monier-Garbet, P.; Guilhem, D.

    1998-01-01

    A visible endoscope system and an infrared camera system have been used to study the flux of carbon from an inertially-cooled graphite limiter in Tore Supra. From the variation in the carbon flux with plasma parameters new data have been obtained describing the dependence of radiation enhanced sublimation (RES) and chemical sputtering on incident ion flux. Other characteristics of RES under plasma operation conditions have also been studied. The dependence of RES on incident deuterium particle flux density is found to be in reasonable agreement with the expected particle flux scaling over a range of particle fluxes varying by a factor ∼ 25, extending the present scaling to higher flux density values. Chemical sputtering has been observed, but only in regions of the limiter with low incident deuterium fluxes. Values inferred for the chemical sputtering yield are similar to those measured with a temperature controlled test limiter in Textor. (author)

  18. Role of wall implantation of charge exchange neutrals in the deuterium retention for Tore Supra long discharges

    International Nuclear Information System (INIS)

    Tsitrone, E.; Reiter, D.; Loarer, T.; Brosset, C.; Bucalossi, J.; Begrambekov, L.; Grisolia, C.; Grosman, A.; Gunn, J.; Hogan, J.; Mitteau, R.; Pegourie, B.; Ghendrih, P.; Reichle, R.; Roubin, P.

    2005-01-01

    In Tore Supra long pulses, particle balance gives evidence that a constant fraction of the injected gas (typically 50%) is retained in the wall for the duration of the shot, showing no sign of wall saturation after more than 6 min of discharge. During the discharge, the retention rate first decreases (phase 1), then remains constant throughout the pulse (phase 2). Phase 1 could be interpreted as implantation of particles combined with a constant codeposition rate, while phase 2 could correspond to codeposition alone, once the implanted surfaces are saturated with deuterium. This paper presents a possible contribution of charge exchange neutrals to the implantation process, based on modelling results with the Eirene neutral transport code. A complex pattern of particle implantation is evidenced, with saturation time constants ranging from less than one to several hundreds seconds, compatible with the experimental behaviour during phase 1

  19. Isotope exchange experiments on TEXTOR and TORE SUPRA using Ion Cyclotron Wall Conditioning and Glow Discharge Conditioning

    International Nuclear Information System (INIS)

    Wauters, T.; Douai, D.; Lyssoivan, A.; Philipps, V.; Bremond, S.; Freisinger, M.; Kreter, A.; Lombard, G.; Marchuk, O.; Mollard, P.; Paul, M.K.; Pegourie, B.; Reimer, H.; Sergienko, G.; Tsitrone, E.; Vervier, M.; Van Wassenhove, G.; Wuenderlich, D.; Van Schoor, M.; Van Oost, G.

    2011-01-01

    This contribution reports on isotope exchange studies with both Ion Cyclotron Wall Conditioning (ICWC) and Glow Discharge Conditioning (GDC) in TEXTOR and TORE SUPRA. The discharges have been carried out in H 2 , D 2 (ICWC and GDC) and He/H 2 mixtures (ICWC). The higher reionization probability in ICWC compared to GDC, following from the 3 to 4 orders of magnitude higher electron density, leads to a lower pumping efficiency of wall desorbed species. GDC has in this analysis (5-10) times higher removal rates of wall desorbed species than ICWC, although the wall release rate is 10 times higher in ICWC. Also the measured high retention during ICWC can be understood as an effect of the high reionization probability. The use of short RF pulses (∼1 s) followed by a larger pumping time significantly improves the ratio of implanted over recovered particles, without severely lowering the total amount of removed particles.

  20. Perfecting of shielding calculation technique against the gamma rays arising from a Tokamak with the TFR experience. Application to the conceptual design Tokamak TORE 2 SUPRA

    International Nuclear Information System (INIS)

    Diop, Cheikh M'Backe.

    1980-09-01

    The conception of the necessary shielding around a conceptual design Tokamak requires to execute an estimated calculation of the doses due to the different radiation sources arising from the machine: the thermonuclear neutron source and the gamma ray source emitted during the interaction of the runaway electrons with the diaphragm. In this study, we propose a theorical method to calculate this gamma source. We tackle also the shielding problem of the conceptual design Tokamak: TORE 2 SUPRA [fr

  1. Soft x-ray tomography for real-time applications: present status at Tore Supra and possible future developments.

    Science.gov (United States)

    Mazon, D; Vezinet, D; Pacella, D; Moreau, D; Gabelieri, L; Romano, A; Malard, P; Mlynar, J; Masset, R; Lotte, P

    2012-06-01

    This paper is focused on the soft x-ray (SXR) tomography system setup at Tore Supra (DTOMOX) and the recent developments made to automatically get precise information about plasma features from inverted data. The first part describes the main aspects of the tomographic inversion optimization process. Several observations are made using this new tool and a set of shape factors is defined to help characterizing the emissivity field in a real-time perspective. The second part presents a detailed off-line analysis comparing the positions of the magnetic axis obtained from a magnetic equilibrium solver, and the maximum of the reconstructed emissivity field for ohmic and heated pulses. A systematic discrepancy of about 5 cm is found in both cases and it is shown that this discrepancy increases during sawtooth crashes. Finally, evidence of radially localized tungsten accumulation with an in-out asymmetry during a lower hybrid current drive pulse is provided to illustrate the DTOMOX capabilities for a precise observation of local phenomena.

  2. Electric Fields near RF Heating and Current Drive Antennas in Tore Supra Measured with Dynamic Stark Effect Spectroscopy*

    Science.gov (United States)

    Klepper, C. C.; Martin, E. H.; Isler, R. C.; Colas, L.; Hillairet, J.; Marandet, Y.; Lotte, Ph.; Colledani, G.; Martin, V.; Hillis, D. L.; Harris, J. H.; Saoutic, B.

    2011-10-01

    Computational models of the interaction between RF waves and the scrape-off layer plasma near ion cyclotron resonant heating (ICRH) and lower hybrid current drive launch antennas are continuously improving. These models mainly predict the RF electric fields produced in the SOL and, therefore, the best measurement for verification of these models would be a direct measurement of these electric fields. Both types of launch antennas are used on Tore Supra and are designed for high power (up to 4MW/antenna) and long pulse (> > 25s) operation. Direct, non-intrusive measurement of the RF electric fields in the vicinity of these structures is achieved by fitting spectral profiles of deuterium Balmer-alpha and Balmer-beta to a model that includes the dynamic, external-field Stark effect, as well as Zeeman splitting and Doppler broadening mechanisms. The measurements are compared to the mentioned, near-field region, RF antenna models. *Work supported in part by the US DOE under Contract No. DE-AC05-00OR22725 with UT-Battelle, LLC.

  3. Energy measurement of fast ions trapped in the toroidal magnetic field ripple of Tore Supra during ICRF heating

    International Nuclear Information System (INIS)

    Basiuk, V.; Becoulet, A.; Grisolia, C.; Hutter, T.; Mayaux, G.; Martin, G.; Saoutic, B.; Vartanian, S.

    1995-01-01

    Direct losses of ions trapped in the toroidal field ripple of Tore Supra using two techniques were made. The first (DRIPPLE I) correlates the ion loss current measured by an electric probe with the ion loss power measured by a calorimeter. As the calorimeter integrates over all particle energies and time, it yields only the averaged lost ion energy. The second technique (DRIPPLE II), still under development, is a Faraday cup positioned and filtered so as to select ions by their Larmor radius. The currents measured are small (1-100 nA), and improvements in instrumentation are needed to take full advantage of the data, but the preliminary results are still useful. During ICRH (hydrogen minority regime, resonance on axis) a direct correlation between the lost ion mean energy and the density of hydrogen was seen. The energy increased when the hydrogen minority density decreased. Moreover, the line averaged density and the lower hybrid heating (LH) had also an effect on fast ion losses. (authors). 3 refs., 7 figs

  4. Absolute spectral characterization of silicon barrier diode: Application to soft X-ray fusion diagnostics at Tore Supra

    International Nuclear Information System (INIS)

    Vezinet, D.; Mazon, D.; Malard, P.

    2013-01-01

    This paper presents an experimental protocol for absolute calibration of photo-detectors. Spectral characterization is achieved by a methodology that unlike the usual line emissions-based method, hinges on the Bremsstrahlung radiation of a Soft X-Ray (SXR) tube only. Although the proposed methodology can be applied virtually to any detector, the application presented in this paper is based on Tore Supra's SXR diagnostics, which uses Silicon Surface Barrier Diodes. The spectral response of these n-p junctions had previously been estimated on a purely empirical basis. This time, a series of second-order effects, like the spatial distribution of the source radiated power or multi-channel analyser non linearity, are taken into account to achieve accurate measurements. Consequently, a parameterised physical model is fitted to experimental results and the existence of an unexpected dead layer (at least 5 μm thick) is evidenced. This contribution also echoes a more general on-going effort in favour of long-term quality of passive radiation measurements on Tokamaks

  5. Q-profile evolution and improved core electron confinement in the full current drive operation on Tore Supra

    International Nuclear Information System (INIS)

    Litaudon, X.; Peysson, Y.; Aniel, T.; Huysmans, G.; Imbeaux, F.; Joffrin, E.; Lasalle, J.; Lotte, Ph.; Schunke, B.; Segui, J.; Tresset, G.; Zabiego, M.

    2000-12-01

    The formation of a core region with improved electron confinement is reported in the recent full current drive operation of Tore Supra where the plasma current is sustained with the Lower Hybrid, LH, wave. Current profile evolution and thermal electron transport coefficients are directly assessed using the data of the new fast electron Bremsstrahlung tomography that provides the most accurate determination of the LH current and power deposition profiles. The spontaneous rise of the core electron temperature observed a few seconds after the application of the LH power is ascribed to a bifurcation towards a state of reduced electron transport. The role of the magnetic shear is invoked to partly stabilize the anomalous electron turbulence. The electron temperature transition occurs when the q-profile evolves towards a non-inductive state with a non-monotonic shape i.e. when the magnetic shear is reduced close to zero in the plasma core. The improved core confinement phase is often terminated by a sudden MHD activity when the minimum q approaches two. (authors)

  6. High Power ICRH scenarios in Tore-Supra: a potential route towards improved core confinement at high density?

    Energy Technology Data Exchange (ETDEWEB)

    Rimini, F.G.; Fenzi-Bonizec, C.; Hoang, G.T.; Bourdelle, C.; Clairet, F.; Elbeze, D.; Gil, C.; Giruzzi, G.; Imbeaux, F.; Joffrin, E.; Lotte, P.; Maget, P.; Schunke, P.; Tsitrone, E. [Association Euratom-CEA, CEA/DSM/DRFC, Centre de Cadarache, 13 - Saint Paul lez Durance (France); Hennequin, P.; Honore, C. [CNRS-Ecole Polytechnique, LPTP, 91 - Palaiseau (France)

    2005-07-01

    As shown by many tokamak experiments, including Tore-Supra, an operational scenario based on tailoring the current profile via a combination of electron heating and fast plasma current ramp is particularly attractive for producing conditions favourable to internal transport barriers (ITBs) development. As we have reported in this paper, however, this is not a foolproof method for producing ITBs. In our case, reversed or flat shear conditions were indeed created, but only transiently and in a very narrow region in the plasma centre, {rho} < 0.3, and the KINEZERO code micro-stability analysis does not indicate that any significant stabilization of ITG (ion temperature gradient) or ETG (electron temperature gradient) modes is taking place. We have used the Cronos transport code to predict how we could redesign the experiment to maximize the probability to obtain more favourable conditions for triggering and sustaining high performance ITBs. Our modelling is done assuming that recycling can be moderated and edge density can be kept lower than in the actual experiments. In this case, with a substantial increase in LHCD power, from 2.5 MW to 8 MW, we could approach conditions of flat current profile over a wide region, extending to half radius, with a significant fraction of the total current, {approx} 70%, being non-inductively driven. The predictive Cronos transport model, which includes local reduction of transport according to magnetic shear, yields a long-lasting wide electron ITB located close to mid-radius.

  7. Steady-state heat and particle removal with the actively cooled Phase III outboard pump limiter in Tore Supra

    International Nuclear Information System (INIS)

    Nygren, R.; Koski, J.; Lutz, T.; McGrath; Miller, J.; Watkins, J.; Guilhem, D.; Chappuis, P.; Cordier, J.; Loarer, T.

    1995-01-01

    Tore Supra's Phase III outboard pump limiter (OPL) is a modular actively-cooled mid-plane limiter, designed for heat and particle removal during long pulse operation. During its initial operation in 1993, the OPL successfully removed about 1 MW of power during ohmicly heated shots of up to 10 s duration and reached (steady state) thermal equilibrium. The particle pumping of the Phase III OPL was found to be about 50% greater than the Phase II OPL which had a radial distance between the last closed flux surface and the entrance of the pumping throat of 3.5 cm compared with only 2.5 cm for the Phase III OPL. This paper gives examples of power distribution over the limiter from IR measurements of surface temperature and from extensively calorimetry (34 thermocouples and 10 flow meters) and compares the distributions with values predicted by a 3D model (HF3D) with a detailed magnetic configuration (e.g., includes field ripple). ((orig.))

  8. Contributions to the design and to the fabrication of the magnet of the toroidal field of Tore Supra

    International Nuclear Information System (INIS)

    Turck, B.

    1992-03-01

    This report is a collection of published papers in French and in English about the design and the qualification of the magnet of the toroidal field of Tore Supra. The development test programme, the controls during conductor manufacturing and the acceptance tests have shown to be the bases for achieving a very low level of rejection for the whole production. A systematic study of the performances correlated to the fabrication conditions has provided valuable informations for the optimization of the manufacturing processes of superconductors. The tests of single coils have enabled the commissioning of a monitoring and protection system specially adapted for this magnet of 18 coils cooled in a superfluid helium bath. After the accident caused by an arcing in one coil of the Torus, and the replacement of the faulty coil, the monitoring and safety discharge system have been adapted. The current in the magnet has been increased up to 1 455 A for 9.3 T on the conductors (nominal values 1 400 A and 9 T). During the last three years (1989-1991) only one transition to normal state has been observed in one coil strongly irradiated after a severe plasma disruption. In these conditions the protection system acted very well and as expected

  9. Soft x-ray tomography for real-time applications: present status at Tore Supra and possible future developments

    International Nuclear Information System (INIS)

    Mazon, D.; Vezinet, D.; Moreau, D.; Malard, P.; Masset, R.; Lotte, P.; Pacella, D.; Gabelieri, L.; Romano, A.; Mlynar, J.

    2012-01-01

    This paper is focused on the soft x-ray (SXR) tomography system setup at Tore Supra (DTOMOX) and the recent developments made to automatically get precise information about plasma features from inverted data. The first part describes the main aspects of the tomographic inversion optimization process. Several observations are made using this new tool and a set of shape factors is defined to help characterizing the emissivity field in a real-time perspective. The second part presents a detailed off-line analysis comparing the positions of the magnetic axis obtained from a magnetic equilibrium solver, and the maximum of the reconstructed emissivity field for ohmic and heated pulses. A systematic discrepancy of about 5 cm is found in both cases and it is shown that this discrepancy increases during sawtooth crashes. Finally, evidence of radially localized tungsten accumulation with an in–out asymmetry during a lower hybrid current drive pulse is provided to illustrate the DTOMOX capabilities for a precise observation of local phenomena.

  10. Implementation of a design and configuration management platform for fusion components on the Tore Supra WEST Project

    Energy Technology Data Exchange (ETDEWEB)

    Benoît, Fabrice, E-mail: fabrice-2.benoit@cea.fr [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Allegretti, Ludovic [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Aumeunier, Marie-Hélène [OPTIS, ZE de La Farlède, F-83078 Toulon Cedex 9 (France); Bucalossi, Jérôme; Doceul, Louis; Faïsse, Frederic; Firdaouss, Medhi; Geynet, Michel; Houtte, Didier van; Larroque, Sébastien; Magaud, Philippe; Maini, Patrick; Missirlian, Marc; Parrat, Hélène [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Robert, Julien [SOFYNE, F-69800 Saint Priest (France)

    2014-10-15

    Highlights: •A design and configuration management platform is under development for managing fusion components lifecycle at CEA. •Design platform ensures an efficient sharing of the data and provides connections between the different software and databases involved in fusion components design. •Design platform rollout on WEST project is ongoing as part of change control and configuration management implementation. -- Abstract: This paper presents the technical solutions and methodologies that are used and under development for managing the design lifecycle of the WEST project (W – for tungsten – Environment in Steady-state Tokamak, upgrade of Tore Supra's with actively cooled tungsten plasma facing components) fusion components and explains the interfaces that are implemented or in construction to connect together the different tools like documents management system, CAD modeler, or simulation codes around the data management backbone. It describes the methodologies used on the WEST project to optimize the design process by managing the engineering data workflow and ensuring the consistency between the different 3D representations for design or analysis as well as the specification or interfaces documents. Finally it explains how this platform contributes to reach the project targets in terms of performance, cost and schedule.

  11. Evidence for a poloidally localized enhancement of radial transport in the scrape-off layer of the Tore Supra tokamak

    International Nuclear Information System (INIS)

    Gunn, J.P.; Boucher, C.; Dionne, M.; Duran, I.; Fuchs, V.; Loarer, T.; Nanobashvili, I.; Panek, R.; Pascal, J.-Y.; Saint-Laurent, F.; Stoeckel, J.; Rompuy, T. van; Zagorski, R.; Adamek, J.; Bucalossi, J.; Dejarnac, R.; Devynck, P.; Hertout, P.; Hron, M.; Lebrun, G.; Moreau, P.; Rimini, F.; Sarkissian, A.; Oost, G. van

    2007-01-01

    Near-sonic parallel flows are systematically observed in the far scrape-off layer (SOL) of the limiter tokamak Tore Supra, as in many L-mode X-point divertor tokamak plasmas. The poloidal variation of the parallel flow has been measured by moving the contact point of a small circular plasma onto limiters at different poloidal angles. The resulting variations of flow are consistent with the existence of a poloidally localized enhancement of radial transport concentrated in a 30 deg. sector near the outboard midplane. If the plasma contact point is placed on the inboard limiters, then the SOL expands to fill all the space between the plasma and the outboard limiters, with density decay lengths between 10 and 20 cm. On the other hand, if the contact point lies on the outboard limiters, the localized plasma outflux is scraped off and the SOL is very thin with decay lengths around 2-3 cm. The outboard radial transport would have to be about two orders of magnitude stronger than inboard to explain these results

  12. Dynamical study of the radial structure of the fluctuations measured by a reciprocating Langmuir probe in Tore Supra

    International Nuclear Information System (INIS)

    Devynck, P.; Antar, G.; Wang, G.; Garbet, X.; Gunn, J.; Pascal, J.Y.

    1999-01-01

    The fluctuations in the Scrape Off Layer (S.O.L.) of Tore Supra are studied with a movable Langmuir probe biased to ion saturation current. The probe system consists of three probes separated poloidally (0.68 cm between two nearby probes). The probe has no magnetic connection to the mid plane limiter on which the plasma is leaning, but the radial profile of the ion saturation current fluctuations displays a dip at the limiter position. At the same location the ion saturation current displays a dip at the limiter position. At the same location the ion saturation current displays an inflexion point. A correlation analysis technique is developed to study the radial behaviour of the fluctuations. It reveals that this dip is associated with a reduction of the poloidal velocity of the fluctuations with no sign reversal. In the dip the mean poloidal correlation length of the fluctuations is also reduced. These observations are consistent with a reduction of the fluctuations by a shear of the radial electric field created at the limiter surface. The autocorrelation time is also calculated. It increases slightly in the dip and is found to be sensitive to both the convection time and lifetime of the turbulent structures, because these quantities are of the same order. (authors)

  13. Implementation of a design and configuration management platform for fusion components on the Tore Supra WEST Project

    International Nuclear Information System (INIS)

    Benoît, Fabrice; Allegretti, Ludovic; Aumeunier, Marie-Hélène; Bucalossi, Jérôme; Doceul, Louis; Faïsse, Frederic; Firdaouss, Medhi; Geynet, Michel; Houtte, Didier van; Larroque, Sébastien; Magaud, Philippe; Maini, Patrick; Missirlian, Marc; Parrat, Hélène; Robert, Julien

    2014-01-01

    Highlights: •A design and configuration management platform is under development for managing fusion components lifecycle at CEA. •Design platform ensures an efficient sharing of the data and provides connections between the different software and databases involved in fusion components design. •Design platform rollout on WEST project is ongoing as part of change control and configuration management implementation. -- Abstract: This paper presents the technical solutions and methodologies that are used and under development for managing the design lifecycle of the WEST project (W – for tungsten – Environment in Steady-state Tokamak, upgrade of Tore Supra's with actively cooled tungsten plasma facing components) fusion components and explains the interfaces that are implemented or in construction to connect together the different tools like documents management system, CAD modeler, or simulation codes around the data management backbone. It describes the methodologies used on the WEST project to optimize the design process by managing the engineering data workflow and ensuring the consistency between the different 3D representations for design or analysis as well as the specification or interfaces documents. Finally it explains how this platform contributes to reach the project targets in terms of performance, cost and schedule

  14. Boundary plasma control with the ergodic divertor

    International Nuclear Information System (INIS)

    Ghendrih, Ph.; Becoulet, M.; Beyer, P.

    1999-01-01

    Ergodic divertor experiments on Tore Supra provide evidence of significant control of plasma-wall interaction. Theoretical investigation of the laminar region (i.e. governed by parallel transport) indicates that control of the plasma state at the target plate can be achieved with plasma states similar to that observed with the axisymmetric divertor. Analysis of the temperature field with a 2-D test particle code allows one to recover the observed spatial modulation and shows that an intrinsic barrier appears to develop at the separatrix. Energy deposition peaking, analysed with a 3-D code, is strongly reduced when moderate transverse transport is considered. Possible control of upstream parameters can thus be achieved in the ergodic region, for instance a lowering of the parallel energy flux by cross field transport. (author)

  15. Boundary plasma control with the ergodic divertor

    International Nuclear Information System (INIS)

    Ghendrih, Ph.; Becoulet, M.; Beyer, P.

    2001-01-01

    Ergodic divertor experiments on Tore Supra provide evidence of significant control of plasma-wall interaction. Theoretical investigation of the laminar region (i.e. governed by parallel transport) indicates that control of the plasma state at the target plate can be achieved with plasma states similar to that observed with the axisymmetric divertor. Analysis of the temperature field with a 2-D test particle code allows one to recover the observed spatial modulation and shows that an intrinsic barrier appears to develop at the separatrix. Energy deposition peaking, analysed with a 3-D code, is strongly reduced when moderate transverse transport is considered. Possible control of upstream parameters can thus be achieved in the ergodic region, for instance a lowering of the parallel energy flux by cross field transport. (author)

  16. Resistive evolution of current profile in tokamaks, application to the optimization of Tore-supra plasma discharges; Evolution resistive du profil de courant dans les Tokamaks, application a l'optimisation des decharges de Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Bregeon, R

    1999-03-01

    In Tokamak plasma physics, current profile shaping has now become a key issue to improve the confinement properties of the plasma discharge. The objective of this work is to study the processes governing the current diffusion when non-inductive current are playing a major role in the discharge. Ultimately, this study aims to identify the key parameters to control the plasma current density profile with external current drive heating systems such as Lower Hybrid Current drive (LHCD) or self generated current drive such as the bootstrap current. Principles of non inductive current drive and heating systems are introduced as well as bootstrap current mechanisms. Then we present the experimental study of plasma parallel electric conductivity to validate existing models. Using these results, the poloidal magnetic field flux diffusion is modelled, using toroidal co-ordinates in order to give an accurate description of the current density profiles evolution. The initial and boundary conditions required for numerical resolution of the diffusion equation are also presented. Finally, we conclude this work with the simulations of two discharges: one with Fast Wave Electron Heating and the second using Lower Hybrid Current Drive. These simulations have multiples aims: validity test of our numerical tool and to show some limits of cylindrical models. Test of electric conductivity and bootstrap current models. To identify the key parameters involved in the current diffusion processes of a high performance plasma discharge on Tore Supra. Such simulations are crucial to determine the amount of non-inductive current required to control and sustain long plasma discharges in steady state. (author)

  17. M.H.D. activity associated with the q=1 surface in the Tore-Supra tokamak; Activite M.H.D. associee a la surface q=1 dans le tokamak Tore-Supra

    Energy Technology Data Exchange (ETDEWEB)

    Cristofani, P.

    1996-02-12

    In order to increase the temperature, density and confinement time of the plasma energy inside tokamak devices, several heating and fuel injection techniques have been used. However, the increase of the energy content of the central part of the plasma leads to instabilities in the confinement magnetic structure which can degrade the confinement properties and the temperature performances. Inside the plasma, the ``q=1`` surface plays an important role in the confinement process. The aim of this thesis is to study the experimental physics related to this surface with the analysis of the ``saw-tooth`` periodical internal relaxations and of the ``snake`` structure. The first chapter gives a general introduction about thermonuclear fusion and a description of the plasma and of its equilibrium. Chapter 2 is devoted to the description of the soft X-ray tomography, the diagnostic technique used in this work. In chapter 3, a theoretical presentation of plasma stability and a comparison with experimental results obtained in the Tore-Supra tokamak are given. The observations of saw-tooth instabilities are presented with the principal theoretical models which are used to explain this phenomenon. The snake density instability localized in the central part of the plasma is described in chapter 4 with an attempt of interpretation. The equation of the size evolution of a magnetic island was modified to test different models which can explain the snake stability. One model is based on the modification of the bootstrap current induced by the presence of the snake, and on the local modification of the current induced by the accumulation of impurities inside the snake. (J.S.). 107 refs.

  18. Determination of electromagnetic modes in oversized corrugated waveguides on the electron cyclotron resonance heating installation at the tokamak Tore Supra; Determination de modes electromagnetiques de guides d'ondes corrugues surdimensionnes sur l'installation de chauffage des electrons de tokamak Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Courtois, L

    2001-03-09

    Electron cyclotron resonance heating (ECRH) in the Tore Supra tokamak constitutes an important step in the research aimed at obtaining thermonuclear fusion reactions. Electron heating is achieved by transmitting an electromagnetic wave from the oscillators (gyrotrons) to the plasma via the fundamental mode, propagating in oversized corrugated waveguides. Maximizing the proportion of the gyrotron power coupled to the fundamental waveguide mode is essential for the good functioning of the transmission line and for maximizing the effect on the plasma. This thesis gives all necessary tools for finding the proportion of the fundamental mode and all other modes present in passive components and at the output of the gyrotron as installed in the Tore Supra ECRH plant. This characterisation is based on obtaining amplitude and phase diagrams of the electric field on a plane transverse to the propagation axis. The most difficult part of obtaining these diagrams is measuring the phase which, despite the very short wavelength, is measured directly at low power levels. At high power levels the phase is numerically reconstructed from amplitude measurements for gyrotron characterisation. A complete theoretical study of the phase reconstruction code is given including its validation with theoretical diagrams. This study allows the realisation of a modal characterisation unit electromagnetic for measurement of radiated beams and usable in each part of the ECRH installation. At the end, the complete modal characterisation is given at low level for a mode converter and also at high level for the first series gyrotron installed at TORE SUPRA. (author)

  19. M.H.D. activity associated with the q=1 surface in the Tore-Supra tokamak

    International Nuclear Information System (INIS)

    Cristofani, P.

    1996-01-01

    In order to increase the temperature, density and confinement time of the plasma energy inside tokamak devices, several heating and fuel injection techniques have been used. However, the increase of the energy content of the central part of the plasma leads to instabilities in the confinement magnetic structure which can degrade the confinement properties and the temperature performances. Inside the plasma, the ''q=1'' surface plays an important role in the confinement process. The aim of this thesis is to study the experimental physics related to this surface with the analysis of the ''saw-tooth'' periodical internal relaxations and of the ''snake'' structure. The first chapter gives a general introduction about thermonuclear fusion and a description of the plasma and of its equilibrium. Chapter 2 is devoted to the description of the soft X-ray tomography, the diagnostic technique used in this work. In chapter 3, a theoretical presentation of plasma stability and a comparison with experimental results obtained in the Tore-Supra tokamak are given. The observations of saw-tooth instabilities are presented with the principal theoretical models which are used to explain this phenomenon. The snake density instability localized in the central part of the plasma is described in chapter 4 with an attempt of interpretation. The equation of the size evolution of a magnetic island was modified to test different models which can explain the snake stability. One model is based on the modification of the bootstrap current induced by the presence of the snake, and on the local modification of the current induced by the accumulation of impurities inside the snake. (J.S.)

  20. A new treatment of the heat transport equation with a transport barrier and applications to ECRH experiments in Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Zou, X.L.; Giruzzi, A.G.; Bouquey, F.; Clary, J.; Darbos, C.; Lennholm, M.; Magne, R.; Segui, J.L. [CEA Cadarache, Dept. de Recherches sur la Fusion Controlee, 13 - Saint-Paul-lez-Durance (France); Clemencon, A. [MIT, Electrochemical Energy Laboratory, Cambridge, MA (United States); Guivarch, C. [Ecole Nationale des Ponts et Chaussees, 77 - Marne-la-Vallee (France)

    2004-07-01

    An exact analytical solution of the electron heat diffusion equation in a cylinder has been found with a step-like diffusion coefficient, plus a monomial increase in the radial direction and a constant damping term. This model is sufficiently general to describe heat diffusion in the presence of a critical gradient threshold or a transport barrier, superimposed to the usual trend of increasing heat diffusivity from the plasma core to the edge. This type of representation allows us to see some well-known properties of heat transport phenomena in a different light. For instance, it has been shown that the contributions of the Eigenmodes to the time dependent solution grow at speeds that depend on the Eigenmode order i.e. at the beginning of the heating phase all the Eigenmodes are equally involved, whereas at the end only the lower order ones are left. This implies, e.g., that high frequency modulation experiments provide a characterization of transport phenomena that is intrinsically different with respect to power balance analysis of a stationary phase. It is particularly useful to analyse power switch on/off events and whenever high frequency modulations are not technically feasible. Low-frequency (1-2 Hz) ECRH modulation experiments have been performed on Tore Supra. A large jump (a factor of 8) in the heat diffusivity has been clearly identified at the ECRH power deposition layer. The amplitude and phase of several harmonics of the Fourier transform of the modulated temperature, as well as the time evolution of the modulated temperature have been reproduced by the analytical solution. The jump is found to be much weaker at lower ECRH power (one gyrotron)

  1. Non-inductive plasmas studies by injection of electron cyclotron waves in the Tore Supra tokamak; Etudes des plasmas non-inductifs par injection d'ondes a la frequence cyclotronique electronique dans le tokamak Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Turco, F

    2008-06-15

    In this work we addressed the issue of the phenomena typical of the non-inductive discharges in the Tore Supra tokamak, probed by means of localised perturbations of the current density profile, performed by electron cyclotron (EC) waves. In order to correctly utilize the current density profile, reconstructed by means of the CRONOS code we performed a sensitivity study on the code results. Concerning the MHD regimes we have shown that a dynamic evolution of the safety factor q which tends to shrink its profile appears to be the cause of the triggering of such regimes. From the operational point of view, deposing the EC current, generated in the same direction of the plasma current, outside the q{sub min} position results hazardous because it causes a rise in q{sub 0} and consequently the shrinking of the q profile which triggers the MHD regimes. On the contrary, the EC counter-current scans show that a very central deposition ({rho}(ECCD) < 0.1) lead almost certainly to an MHD regime, while a more external countercurrent generation has generally the quality of creating internal transport barriers (ITBs). The phenomenon of non-linear temperature oscillations (the O-regime) has also been addressed, to provide an analytical description as well as from the experimental point of view, concerning the triggering and canceling of the oscillating phases. By constructing a non-linear predator-prey system with noise, solved on two regions of space coupled by a diffusion term, we could reproduce the experimental temperature oscillations: this study allowed us to confirm that the oscillatory phenomenon is the manifestation of a Lotka-Volterra like coupling between j and T{sub e}. The experimental analysis led to the identification of the mechanism at the origin of the triggering and canceling of the O-regime in presence of a perturbation in a specific shape of magnetic shear perturbation. These results have been reproduced by the simulations preformed with the integrated

  2. Evolution of the bonding defect reported on the tiles of the toroidal pumped limiter of the Tore Supra tokamak with infrared analysis

    International Nuclear Information System (INIS)

    Cai Laizhong; Gauthier, Eric; Corre, Yann; Loarer, Thierry; Missirlian, Marc; Martin, Vincent; Moncada, Victor

    2012-01-01

    The bonding of plasma-facing component (PFC) tiles and their possible defects need to be monitored to evaluate the safety during long pulse plasma operations and prevent critical failure, which is very important for ITER and next-step fusion devices. The defect evolutions of two toroidal pumped limiter (TPL) tiles are investigated by analysing the infrared images obtained during Tore Supra experiments from 2006 to 2010 (about 10 000 plasma discharges). The evolution of the defect is characterized by the surface temperature reached in stationary discharge conditions. The comparison of the defect tiles with neighbouring tiles (with no defect) and the evolutions are carried out through the thermal time constants of the tiles. The results show that the two tiles are slowly deteriorating during plasma operation and no plateau of the deterioration is observed in the considered period. By comparing the defect evolutions with the modelling results calculated by CAST3M, the current state of the defect tiles is identified. The defects are significant (about 30% of the tile length or area) and need to be followed and monitored further in the next experimental campaigns of Tore Supra.

  3. Real time control of fully non-inductive operation in Tore Supra leading to 6 minutes, 1 giga-joule plasma discharges

    International Nuclear Information System (INIS)

    Van Houtte, D.; Martin, G.; Becoulet, A.; Saoutic, B.

    2004-01-01

    The experimental programme of Tore Supra (a = 0.72 m, R = 2.4 m, I p T < 4.5 T) has been devoted in 2003 to study simultaneously heat removal capability and particle exhaust in steady-state fully non-inductive current drive discharges. This required both advanced technology integration and steady-state real time plasma control. In particular, an improvement of the plasma position within a few millimetre range, and new real time cross controls between radio frequency (RF) power and various actuators built around a shared memory network, have allowed Tore Supra to access a powerful steady-state regime with an improved safety level for the actively cooled plasma facing components. Feedback controlled fully non-inductive plasma discharges have been sustained in a steady-state regime up to 6 minutes with a new world record of injected-extracted energy exceeding 1 GJ. Advanced tools, experimental results and brief physics analysis of these discharges are presented and discussed. (authors)

  4. Real time control of fully non-inductive operation in Tore Supra leading to 6 minutes, 1 giga-joule plasma discharges

    Energy Technology Data Exchange (ETDEWEB)

    Van Houtte, D.; Martin, G.; Becoulet, A.; Saoutic, B

    2004-07-01

    The experimental programme of Tore Supra (a = 0.72 m, R = 2.4 m, I{sub p} < 1.7 MA, B{sub T} < 4.5 T) has been devoted in 2003 to study simultaneously heat removal capability and particle exhaust in steady-state fully non-inductive current drive discharges. This required both advanced technology integration and steady-state real time plasma control. In particular, an improvement of the plasma position within a few millimetre range, and new real time cross controls between radio frequency (RF) power and various actuators built around a shared memory network, have allowed Tore Supra to access a powerful steady-state regime with an improved safety level for the actively cooled plasma facing components. Feedback controlled fully non-inductive plasma discharges have been sustained in a steady-state regime up to 6 minutes with a new world record of injected-extracted energy exceeding 1 GJ. Advanced tools, experimental results and brief physics analysis of these discharges are presented and discussed. (authors)

  5. Calculation of heat fluxes induced by radio frequency heating on the actively cooled protections of ion cyclotron resonant heating (ICRH) and lower hybrid (LH) antennas in Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Ritz, G., E-mail: Guillaume.ritz@gmail.com [CEA, Institut de la Recherche sur la Fusion Magnétique (IRFM), 13108 Saint Paul-lez-Durance (France); Corre, Y., E-mail: Yann.corre@cea.fr [CEA, Institut de la Recherche sur la Fusion Magnétique (IRFM), 13108 Saint Paul-lez-Durance (France); Rault, M.; Missirlian, M. [CEA, Institut de la Recherche sur la Fusion Magnétique (IRFM), 13108 Saint Paul-lez-Durance (France); Portafaix, C. [ITER Organization, Route de Vinon-sur-Verdon, 13115 Saint Paul-lez-Durance (France); Martinez, A.; Ekedahl, A.; Colas, L.; Guilhem, D.; Salami, M.; Loarer, T. [CEA, Institut de la Recherche sur la Fusion Magnétique (IRFM), 13108 Saint Paul-lez-Durance (France)

    2013-10-15

    Highlights: ► The heat flux generated by radiofrequency (RF) heating was calculated using Tore Supra's heating antennas. ► The highest heat flux value, generated by ions accelerated in RF-rectified sheath potentials, was 5 MW/m{sup 2}. ► The heat flux on the limiters of antennas was in the same order of magnitude as that on the toroidal pumping limiter. -- Abstract: Lower hybrid current drive (LHCD) and ion cyclotron resonance heating (ICRH) are recognized as important auxiliary heating and current drive methods for present and next step fusion devices. However, these radio frequency (RF) systems generate a heat flux up to several MW/m{sup 2} on the RF antennas during plasma operation. This paper focuses on the determination of the heat flux deposited on the lateral protections of the RF antennas in Tore Supra. The heat flux was calculated by finite element method (FEM) using a model of the lateral protection. The FEM calculation was based on surface temperature measurements using infrared cameras monitoring the RF antennas. The heat flux related to the acceleration of electrons in front of the LHCD grills (LHCD active) and to the acceleration of ions in RF-rectified sheath potentials (ICRH active) were calculated. Complementary results on the heat flux related to fast ions (ICRH active with a relatively low magnetic field) are also reported in this paper.

  6. Leak tightness tests on actively cooled plasma facing components: Lessons learned from Tore Supra experience and perspectives for the new fusion machines

    Energy Technology Data Exchange (ETDEWEB)

    Chantant, M., E-mail: michel.chantant@cea.fr; Lambert, R.; Gargiulo, L.; Hatchressian, J.-C.; Guilhem, D.; Samaille, F.; Soler, B.

    2015-10-15

    Highlights: • Test procedures for the qualification of the tightness of actively cooled plasma facing components were defined. • The test is performed after the component manufacturing and before its set-up in the vacuum vessel. • It allows improving the fusion machine availability. • The lessons of tests over 20 years at Tore Supra are presented. - Abstract: The fusion machines under development or construction (ITER, W7X) use several hundreds of actively cooled plasma facing components (ACPFC). They are submitted to leak tightness requirements in order to get an appropriate vacuum level in the vessel to create the plasma. During the ACPFC manufacturing and before their installation in the machine, their leak tightness performance must be measured to check that they fulfill the vacuum requirements. A relevant procedure is needed which allows to segregate potential defects. It must also be optimized in terms of test duration and costs. Tore Supra, as an actively cooled Tokamak, experienced several leaks on ACPFCs during the commissioning and during the operation of the machine. A test procedure was then defined and several test facilities were set-up. Since 1990 the tightness of all the new ACPFCs is systematically tested before their installation in Tore Supra. During the qualification test, the component is set up in a vacuum test tank, and its cooling circuits are pressurized with helium. It is submitted to 3 temperature cycles from room temperature up to the baking temperature level in Tore Supra (200 °C) and two pressurization tests are performed (6 MPa at room temperature and 4 MPa at 200 °C) at each stage. At the end of the last cycle when the ACPFC is at room temperature and pressurized with helium at 6 MPa, the measured leak rate must be lower than 5 × 10{sup −11} Pa m{sup 3} s{sup −1}, the pressure in the test tank being <5 × 10{sup −5} Pa. A large experience has been gained on ACPFCs with carbon parts on stainless steel and Cu

  7. Manufacturing process and tests of a Lower Hybrid Passive-Active Multijunction launcher for long pulse experiments on Tore-Supra

    International Nuclear Information System (INIS)

    Guilhem, D.; Samaille, F.; Bertrand, B.; Lipa, M.; Achard, J.; Agarici, G.; Argouarch, A.; Armitano, A.; Belo, J.H.; Bej, Z.; Berger-By, G.; Bouquey, F.; Brun, C.; Chantant, M.; Corbel, E.; Delmas, E.; Delpech, L.; Doceul, L.; Ekedahl, A.; Faisse, F.

    2011-01-01

    A new concept of multijunction-type antenna has been developed, the Passive-Active Multijunction, which improves the cooling of the waveguides and the damping of the neutron energy (for ITER) compared to Full Active Multijunction. Due to the complexity of the structures, prototypes of the mode converters and of the Passive-Active-Multijunction launcher were fabricated and tested, in order to validate the different manufacturing processes and the manufacturer's capability to face this challenging project. This paper describes the manufacturing process, the tests of the various prototypes and the construction of the final Passive-Active-Multijunction launcher, which entered into operation in October 2009. It has been commissioned and is fully operational on the Tore-Supra tokamak, since design objectives were reached in March 2010: 2.75 MW - 78 s, power density of 25 MW/m 2 in active waveguides, steady-state apparent surface temperatures <350 deg. C; 10 cm long distance coupling.

  8. MHD stability of (2,1) tearing mode: an issue for the preforming phase of Tore Supra non-inductive discharges

    International Nuclear Information System (INIS)

    Maget, P.; Luetjens, H.; Huysmans, G.; Moreau, Ph.; Schunke, B.; Segui, J.-L.; Garbet, X.; Joffrin, E.; Luciani, J.F.

    2007-01-01

    The early phase of a tokamak plasma discharge can have a dramatic impact on the main heating phase. This has been a persistent problem for the development of the steady state, fully non-inductive scenario using lower hybrid current drive (LHCD) on Tore Supra. The present paper reports on recent experimental and numerical investigations showing that a tearing mode coupled to the internal kink grows on q = 2 in the ohmic phase when the total current is too low, due to the weakening of field line curvature stabilization. Then, the application of LHCD drives the island to a larger size and undermines the development of the non-inductive phase. Decreasing the edge safety factor or increasing the Lundquist number S is found to be beneficial in both the linear and non-linear MHD analyses. The experimental database, which allows covering the edge safety factor dependence, supports this interpretation

  9. Design, fabrication and testing of an improved high heat flux element, experience feedback on steady state plasma facing components in Tore Supra

    International Nuclear Information System (INIS)

    Schlosser, J.; Chappuis, P.; Chatelier, M.; Durocher, A.; Guilheim, D.; Lipa, M.; Mitteau, R.; Tonon, G.; Tsitrone, E.

    1998-01-01

    Actively cooled plasma facing components (PFC) have been developed and used in Tore Supra since 1985. One of the main technological problem is due to the expansion mismatch between graphite armour and metallic heat sink material. A first technology used graphite tiles with or without a reinforcement and a compliant layer, brazed with titanium copper-silver (TiCuAg) alloy. The next technology used carbon fiber material (CFC) tiles with a 2 mm pure copper compliant layer, since the good mechanical strength of the CFC allowed the reinforcement layer to be suppressed. No destructive inspection during the manufacturing procedure was found to be essential to insure a good reliability of the elements. (orig.)

  10. Role of the current density profile on drift wave stability in internal transport barrier reversed magnetic shear experiments at JET and Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Fourment, C; Hoang, G T; Eriksson, L-G; Garbet, X; Litaudon, X; Tresset, G [EURATOM-CEA Association, CEA/DSM/DRFC, CEA Cadarache, 13108 St Paul-lez-Durance (France)

    2003-03-01

    The role of the current density profile on drift wave stability is investigated using a linear electrostatic gyro-kinetic code. The growth rates are shown to have a linear dependence on the normalized temperature gradients above a certain threshold. A parametric study of the threshold shows a dramatic stabilizing effect of negative magnetic shear, especially for large scale instabilities. A set of handy formulae fitting the threshold as a function of the magnetic shear and the safety factor is proposed. Analysis of reversed magnetic shear discharges with internal transport barrier (ITB) in JET shows that ion ITBs can be triggered by the negative magnetic shear in the core of the plasma. Subsequently, the increase of the ExB shearing rate allows for the expansion of the ITB, despite the increase of the linear growth rates due to the temperature gradient peaking. In the case of the electron ITB obtained in the Tore Supra LHEP mode, the central increase of the confinement is associated with the stabilization of large scale trapped electron modes by the negative magnetic shear effect, whereas the steep electron temperature gradient destabilizes the small scale electron temperature gradient modes, which prevent the electron heat transport to reach neoclassical levels.

  11. 2D and 3D modeling of wave propagation in cold magnetized plasma near the Tore Supra ICRH antenna relying on the perfecly matched layer technique

    International Nuclear Information System (INIS)

    Jacquot, J; Colas, L; Clairet, F; Goniche, M; Hillairet, J; Lombard, G; Heuraux, S; Milanesio, D

    2013-01-01

    A novel method to simulate ion cyclotron wave coupling in the edge of a tokamak plasma with the finite element technique is presented. It is applied in the commercial software COMSOL Multiphysics. Its main features include the perfectly matched layer (PML) technique to emulate radiating boundary conditions beyond a critical cutoff layer for the fast wave (FW), full-wave propagation across the inhomogeneous cold peripheral plasma and a detailed description of the wave launcher geometry. The PML technique, while widely used in numerical simulations of wave propagation, has scarcely been used for magnetized plasmas, due to specificities of this gyrotropic material. A versatile PML formulation, valid for full dielectric tensors, is summarized and interpreted as wave propagation in an artificial medium. The behavior of this technique has been checked for plane waves on homogeneous plasmas. Wave reflection has been quantified and compared to analytical predictions. An incompatibility issue for adapting the PML for forward (FW) and backward (slow wave (SW)) propagating waves simultaneously has been evidenced. In a tokamak plasma, this critical issue is overcome by taking advantage of the inhomogeneous density profile to reflect the SW before it reaches the PML. The simulated coupling properties of a Tore Supra ion cyclotron resonance heating (ICRH) antenna have been compared to experimental values in a situation of good single-pass absorption. The necessary antenna elements to include in the geometry to recover the coupling properties obtained experimentally are also discussed. (paper)

  12. The effect of the ergodic divertor on electron thermal confinement

    International Nuclear Information System (INIS)

    Harris, G.R.; Capes, H.; Garbet, X.

    1992-06-01

    The thermal confinement within the confinement zone of Tore Supra ohmically heated deuterium plasmas bounded by the ergodic divertor (ED) configuration is studied in a 1 1/2D analysis of the local power balance. Although the edge electron temperature and mean electron density (n e ) are both on average halved with application of the ED, the mean electron thermal diffusivity χ e shows the same density dependence as exhibited by standard ohmic limiter discharges, i.e., an Alcator-like inverse dependence on (n e ) at low density and a saturation at high density. The ion thermal transport at low to medium densities in both limiter and ED discharges is between 10 to 20 times that predicted by neoclassical theory. Comparing ED and limiter plasmas of the same density, a strong plasma decontamination is observed, with a reduction, in Z eff by between 1.0 to 1.5. The effective decoupling of (n e ) and Z eff by the ED and the invariant behaviour of χ e imply that electron thermal transport is only weakly dependent on Z eff in ohmic Tore Supra discharges

  13. Analysis of density fluctuations in the Tore Supra tokamak. Up-down asymmetries and limiter effect on plasma turbulence; Etude des fluctuations de density dans les plasmas du tokamak Tore Supra. Asymetries haut-bas et effet du limiteur sur la turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Fenzi, Ch

    1999-10-29

    In magnetic fusion devices, the optimisation of the power deposition profile on plasma facing components crucially depends on the heat diffusivity across the magnetic field fines, which is determined by the plasma edge turbulence. In this regard, spatial asymmetries of plasma edge turbulence are of great interest. In this work, we interest in up-down asymmetries of density fluctuations which are usually observed in Tore Supra, using a coherent light scattering experiment. It is shown that these asymmetries are correlated to the plasma edge geometrical configuration (plasma facing components, limiters). In fact, the plasma-limiter interaction induces locally in the plasma edge and the SOL (r/a > 0.9) an additional turbulence with short correlation length along the magnetic field fines, which spreads in the plasma core (0.9 {>=} r/a {>=} 0.5). The resultant up-down asymmetry weakly depends on density, increases with the edge safety factor, and inverts when the plasma current direction is reversed. Such up-down asymmetry observations bring strong impact on edge turbulence and transport models, which usually predict a ballooning of the turbulence in the high-field side but not an up-down asymmetry. A possible model is proposed here, based on the Kelvin Helmholtz instability. (author)

  14. Study of the non inductive current generation in Tore Supra and application to the operational scenario of a continuous tokamak; Etude de la generation de courant non inductive dans Tore Supra et application aux scenarios operationnels d`un tokamak continu

    Energy Technology Data Exchange (ETDEWEB)

    Kazarian-Vibert, F.

    1996-07-05

    Lower Hybrid Current Drive in tokamak plasmas allows to obtain continuous operations, which constitute a necessary step towards a definition of a thermonuclear fusion reactor. The objectives of this work is to define and study fully non inductive steady-state scenarios on Tore Supra. The current diffusion equation is solved to determined precisely the inductive and non inductive current density profiles and their influence on thee time evolution of a discharge. Then, a new operation mode is studied theoretically and experimentally. In this scenario, the transformer primary circuit voltage is controlled in such a way that the flux consumption vanishes. It allows to achieve full steady-state discharges in a fast and reproducible manner. A theoretical flux consumption scaling law during plasma current ramp-up assisted by Lower-Hybrid waves is presented and validated by experimental data, in view to minimized this consumption. The influence of a non monotonic current profile on the confinement and the transport of energy in the plasma is also clearly illustrated by experiments. (author). 138 refs., 16 figs., 1 tab.

  15. The ergodic divertor a way to prevent major disruptions

    International Nuclear Information System (INIS)

    Vallet, J.C.; Poutchy, L.; Mohamed-Benkadda, M.S.; Edery, D.; Joffrin, E.; Lecoustey, P.; Pecquet, A.L.; Samain, A.; Talvard, M.

    1991-01-01

    The disruptions are one of the major obstacles to present day tokamaks extrapolation to fusion reactors. We have recently proposed a piloting discharge strategy on TORE SUPRA to prevent density limit disruptions. This strategy is based on the use of the Ergodic Divertor (ED). We have observed that the ED stabilizes the m=2 n=1 tearing mode and that in deuterium discharges limited by the outboard limiter it induces a fast decrease of the plasma density. The piloting strategy is taken in three steps: 1) the approach of the density limit is detected by a threshold on the MHD activity amplitude; 2) the gas puff is switched off; 3) the ED is turned on. Then the m=2 n=1 tearing mode is stabilized the density decreases and the disruption is avoided. This strategy has already been successully tested on about 20 specific deuterium shots with 2.5< q(a)<4.5 in which the density limit is approached by ramping up the density with gas puffing. In this paper, experimental data are reported and analyzed. First, the principle of the ED and the density limit disruption phenomenology are briefly recalled. Then the ED effect on plasma density, radiated power and MHD activity are analyzed, and the piloting strategy to prevent density limit disruptions is discussed

  16. Plasma wall particle balance in Tore Supra

    International Nuclear Information System (INIS)

    Grisolia, C.; Ghendrih, P.; Pegourie, B.; Grosman, A.

    1992-01-01

    A comprehensive study of the particle balance between the carbon wall and the plasma is presented. One finds that the effective particle content of the wall which governs the plasma equilibrium density departs from the deposited number of particles. This effect is dominant for the fully desaturated wall. A scaling law of the plasma density in terms of the wall effective particle content has been obtained. Moreover, the experimental data allows to estimate the plasma particle confinement time. Values ranging from 0.2 s to 0.5 s are found depending on the density. An analytical functional dependence of the particle confinement time is obtained

  17. New Tore Supra steady state operating scenario

    International Nuclear Information System (INIS)

    Martin, G.; Parlange, F.; van Houtte, D.; Wijnands, T.

    1995-01-01

    This document deals with plasma control in steady state conditions. A new plasma control systems enabling feedback control of global plasma equilibrium parameters has been developed. It also enables to operate plasma discharge in steady state regime. (TEC). 4 refs., 5 figs

  18. Lectures on ergodic theory

    CERN Document Server

    Halmos, Paul R

    2017-01-01

    This concise classic by a well-known master of mathematical exposition covers recurrence, ergodic theorems, ergodicity and mixing properties, and the relation between conjugacy and equivalence. 1956 edition.

  19. Invitation to ergodic theory

    CERN Document Server

    Silva, C E

    2007-01-01

    This book is an introduction to basic concepts in ergodic theory such as recurrence, ergodicity, the ergodic theorem, mixing, and weak mixing. It does not assume knowledge of measure theory; all the results needed from measure theory are presented from scratch. In particular, the book includes a detailed construction of the Lebesgue measure on the real line and an introduction to measure spaces up to the Carathéodory extension theorem. It also develops the Lebesgue theory of integration, including the dominated convergence theorem and an introduction to the Lebesgue L^pspaces. Several examples of a dynamical system are developed in detail to illustrate various dynamical concepts. These include in particular the baker's transformation, irrational rotations, the dyadic odometer, the Hajian-Kakutani transformation, the Gauss transformation, and the Chacón transformation. There is a detailed discussion of cutting and stacking transformations in ergodic theory. The book includes several exercises and some open q...

  20. The division of plasma physics

    International Nuclear Information System (INIS)

    Evans, T.E.; Guilhem, D.; Klepper, C.C.

    1990-07-01

    The investigations presented in the 31th meeting on plasma physics were: the main results and observations during the ergodic divertor experiments in Tore Supra tokamak; the modifications of power scrape-off-length and power deposition during various configurations in Tore Supra plasmas; the results of pressure measurements and particle fluxes in the Tore Supra pump limiter

  1. Quantization ambiguity, ergodicity and semiclassics

    International Nuclear Information System (INIS)

    Kaplan, Lev

    2002-01-01

    It is well known that almost all eigenstates of a classically ergodic system are individually ergodic on coarse-grained scales. This has important implications for the quantization ambiguity in ergodic systems: the difference between alternative quantizations is suppressed compared with the O( h-bar 2 ) ambiguity in the integrable or regular case. For two-dimensional ergodic systems in the high-energy regime, individual eigenstates are independent of the choice of quantization procedure, in contrast with the regular case, where even the ordering of eigenlevels is ambiguous. Surprisingly, semiclassical methods are shown to be much more precise in any dimension for chaotic than for integrable systems

  2. Plasma turbulence measured by fast sweep reflectometry on Tore Supra

    International Nuclear Information System (INIS)

    Clairet, F.; Vermare, L.; Leclert, G.

    2004-01-01

    Traditionally devoted to electron density profile measurement we show that fast frequency sweeping reflectometry technique can bring valuable and innovative measurements onto plasma turbulence. While fast frequency sweeping technique is traditionally devoted to electron density radial profile measurements we show in this paper how we can handle the fluctuations of the reflected signal to recover plasma density fluctuation measurements with a high spatial and temporal resolution. Large size turbulence related to magneto-hydrodynamic (MHD) activity and the associated magnetic islands can be detected. The radial profile of the micro-turbulence, which is responsible for plasma anomalous transport processes, is experimentally determined through the fluctuation of the reflected phase signal. (authors)

  3. Plasma turbulence measured by fast sweep reflectometry on Tore Supra

    International Nuclear Information System (INIS)

    Clairet, F.; Vermare, L.; Heuraux, S.; Leclert, G.

    2004-01-01

    Traditionally devoted to electron density profile measurement we show that fast frequency sweeping reflectometry technique can bring valuable and innovative measurements onto plasma turbulence. While fast frequency sweeping technique is traditionally devoted to electron density radial profile measurements we show in this paper how we can handle the fluctuations of the reflected signal to recover plasma density fluctuation measurements with a high spatial and temporal resolution. Large size turbulence related to magneto-hydrodynamic (MHD) activity and the associated magnetic islands can be detected. The radial profile of the micro-turbulence, which is responsible for plasma anomalous transport processes, is experimentally determined through the fluctuation of the reflected phase signal

  4. Electron transport and improved confinement on Tore Supra

    International Nuclear Information System (INIS)

    Hoang, G.T.; Bourdelle, C.; Garbet, X.; Aniel, T.; Giruzzi, G.; Ottaviani, M.; Horton, W.; Zhu, P.; Budny, R.V.

    2001-01-01

    Magnetic shear is found to play an important role for triggering various improved confinement regimes through the electron channel. A wide database of hot electron plasmas (T e >2T i ) heated by fast wave electron heating (FWEH) is analyzed for electron thermal transport. A critical gradient is clearly observed. It is found that the critical gradient linearly increases with the ratio between local magnetic shear (s) and safety factor (q). The Horton model, based on the electromagnetic turbulence driven by the electron temperature gradient (ETG) mode, is found to be a good candidate for electron transport modeling. (author)

  5. Carbon migration and deuterium retention in Tore Supra

    International Nuclear Information System (INIS)

    Panayotis, Stephanie

    2013-01-01

    Three reasons can be invoked to characterize and control plasma-surface interaction in thermonuclear fusion devices: 1/ the plasma erosion limits the lifetime of the first wall components, 2/ the penetration of eroded particles in the plasma is the cause of fuel dilution and loss of performance and 3/ part of the fuel (D/T) is trapped in the wall or layers resulting from the redeposition of eroded particles. In carbon wall devices, points 1/ and 3/ are strongly coupled due to the chemical affinity of carbon with hydrogen or its isotopes. If the erosion/redeposition balance is often obtained from post-mortem analyses of samples extracted from the vacuum chamber, two methods are currently used to build the fuel balance, and particularly to quantify the amount of which trapped in the vessel: the post-mortem analyses cited above, and discharge per discharge gas balance. Estimations by these two methods exhibit a significant discrepancy, the amount of trapped hydrogen estimated by post-mortem being typically four times lower than that obtained from gas balance. The main reason is that the former value is resolved in space (it depends of the location of the sample in the vacuum vessel) but integrated in time (it concerns the whole period during which the sample was in the device), when the latter is a global value for the whole machine but is resolved discharge per discharge. For solving the discrepancy, one must perform post-mortem analyses on a number of samples large enough for covering the whole vessel and extend gas balance measurements to the whole period during which the considered first wall elements were used, including the period in between plasmas and vents. (author) [fr

  6. Scrape-off layer flows in the Tore Supra tokamak

    Czech Academy of Sciences Publication Activity Database

    Gunn, J. P.; Boucher, C.; Dionne, M.; Ďuran, Ivan; Fuchs, Vladimír; Loarer, T.; Pánek, Radomír; Saint Laurent, F.; Stöckel, Jan; Adámek, Jiří; Bucalossi, J.; Dejarnac, Renaud; Devynck, P.; Hertout, P.; Hron, Martin; Nanobashvili, I.; Rimini, F.G.; Sarkissian, A.

    2006-01-01

    Roč. 812, - (2006), s. 27-34 ISSN 0094-243X. [AIP Conference Proceedings. Opole-Turawa, 06.09.2006-09.09.2006] R&D Projects: GA ČR GP202/03/P062 Institutional research plan: CEZ:AV0Z20430508 Keywords : tokamak * scrape-off layer * plasma flow * radial transport * Mach probe Subject RIV: BL - Plasma and Gas Discharge Physics http://proceedings.aip.org/dbt/dbt.jsp?KEY=APCPCS&Volume=812&Issue=1

  7. Electron density profile measurements by microwave reflectometry on Tore Supra

    International Nuclear Information System (INIS)

    Clairet, F.; Paume, M.; Chareau, J.M.

    1995-01-01

    A proposal is presented developing reflectometry diagnostic for electron density profile measurements as routine diagnostic without manual intervention as achieved at JET. Since density fluctuations seriously perturb the reflected signal and the measurement of the group delay, a method is described to overcome the irrelevant results with the help of an adaptive filtering technique. Accurate profiles are estimated for about 70% of the shots. (author) 3 refs.; 6 figs

  8. Coupling structure calculations for ion cyclotron heating of Tore Supra

    International Nuclear Information System (INIS)

    Bannelier, P.

    1986-12-01

    Two structures are studied: antennas and waveguides. After some recalls on transmission lines with losses, the theory is applied to antennas with inner adaptation: the problem is to calculate the impedance necessary for complete adaptation of antenna to the power line and the generator. The Faraday screen role is detailed and studied: the per-unit length loss resistance due to ohmic losses in the screen which lower the plasma-coupled maximum power. Waveguide coupling theory is also presented. Coupling between wave guide and plasma is evaluated [fr

  9. Ergodic theory and dynamical systems

    CERN Document Server

    Coudène, Yves

    2016-01-01

    This textbook is a self-contained and easy-to-read introduction to ergodic theory and the theory of dynamical systems, with a particular emphasis on chaotic dynamics. This book contains a broad selection of topics and explores the fundamental ideas of the subject. Starting with basic notions such as ergodicity, mixing, and isomorphisms of dynamical systems, the book then focuses on several chaotic transformations with hyperbolic dynamics, before moving on to topics such as entropy, information theory, ergodic decomposition and measurable partitions. Detailed explanations are accompanied by numerous examples, including interval maps, Bernoulli shifts, toral endomorphisms, geodesic flow on negatively curved manifolds, Morse-Smale systems, rational maps on the Riemann sphere and strange attractors. Ergodic Theory and Dynamical Systems will appeal to graduate students as well as researchers looking for an introduction to the subject. While gentle on the beginning student, the book also contains a number of commen...

  10. Ergodic averages via dominating processes

    DEFF Research Database (Denmark)

    Møller, Jesper; Mengersen, Kerrie

    2006-01-01

    We show how the mean of a monotone function (defined on a state space equipped with a partial ordering) can be estimated, using ergodic averages calculated from upper and lower dominating processes of a stationary irreducible Markov chain. In particular, we do not need to simulate the stationary...... Markov chain and we eliminate the problem of whether an appropriate burn-in is determined or not. Moreover, when a central limit theorem applies, we show how confidence intervals for the mean can be estimated by bounding the asymptotic variance of the ergodic average based on the equilibrium chain....

  11. Intuitionistic supra fuzzy topological spaces

    International Nuclear Information System (INIS)

    Abbas, S.E.

    2004-01-01

    In this paper, We introduce an intuitionistic supra fuzzy closure space and investigate the relationship between intuitionistic supra fuzzy topological spaces and intuitionistic supra fuzzy closure spaces. Moreover, we can obtain intuitionistic supra fuzzy topological space induced by an intuitionistic fuzzy bitopological space. We study the relationship between intuitionistic supra fuzzy closure space and the intuitionistic supra fuzzy topological space induced by an intuitionistic fuzzy bitopological space

  12. Ergodic theory independence and dichotomies

    CERN Document Server

    Kerr, David

    2016-01-01

    This book provides an introduction to the ergodic theory and topological dynamics of actions of countable groups. It is organized around the theme of probabilistic and combinatorial independence, and highlights the complementary roles of the asymptotic and the perturbative in its comprehensive treatment of the core concepts of weak mixing, compactness, entropy, and amenability. The more advanced material includes Popa's cocycle superrigidity, the Furstenberg-Zimmer structure theorem, and sofic entropy. The structure of the book is designed to be flexible enough to serve a variety of readers. The discussion of dynamics is developed from scratch assuming some rudimentary functional analysis, measure theory, and topology, and parts of the text can be used as an introductory course. Researchers in ergodic theory and related areas will also find the book valuable as a reference.

  13. Ergodicity of polygonal slap maps

    International Nuclear Information System (INIS)

    Del Magno, Gianluigi; Pedro Gaivão, José; Lopes Dias, João; Duarte, Pedro

    2014-01-01

    Polygonal slap maps are piecewise affine expanding maps of the interval obtained by projecting the sides of a polygon along their normals onto the perimeter of the polygon. These maps arise in the study of polygonal billiards with non-specular reflection laws. We study the absolutely continuous invariant probabilities (acips) of the slap maps for several polygons, including regular polygons and triangles. We also present a general method for constructing polygons with slap maps with more than one ergodic acip. (paper)

  14. The large deviations theorem and ergodicity

    International Nuclear Information System (INIS)

    Gu Rongbao

    2007-01-01

    In this paper, some relationships between stochastic and topological properties of dynamical systems are studied. For a continuous map f from a compact metric space X into itself, we show that if f satisfies the large deviations theorem then it is topologically ergodic. Moreover, we introduce the topologically strong ergodicity, and prove that if f is a topologically strongly ergodic map satisfying the large deviations theorem then it is sensitively dependent on initial conditions

  15. The ergodic theory of lattice subgroups

    CERN Document Server

    Gorodnik, Alexander

    2010-01-01

    The results established in this book constitute a new departure in ergodic theory and a significant expansion of its scope. Traditional ergodic theorems focused on amenable groups, and relied on the existence of an asymptotically invariant sequence in the group, the resulting maximal inequalities based on covering arguments, and the transference principle. Here, Alexander Gorodnik and Amos Nevo develop a systematic general approach to the proof of ergodic theorems for a large class of non-amenable locally compact groups and their lattice subgroups. Simple general conditions on the spectral theory of the group and the regularity of the averaging sets are formulated, which suffice to guarantee convergence to the ergodic mean

  16. Transport modelling for ergodic configurations

    International Nuclear Information System (INIS)

    Runov, A.; Kasilov, S.V.; McTaggart, N.; Schneider, R.; Bonnin, X.; Zagorski, R.; Reiter, D.

    2004-01-01

    The effect of ergodization, either by additional coils like in TEXTOR-dynamic ergodic divertor (DED) or by intrinsic plasma effects like in W7-X, defines the need for transport models that are able to describe the ergodic configuration properly. A prerequisite for this is the concept of local magnetic coordinates allowing a correct discretization with minimized numerical errors. For these coordinates the appropriate full metric tensor has to be known. To study the transport in complex edge geometries (in particular for W7-X) two possible methods are used. First, a finite-difference discretization of the transport equations on a custom-tailored grid in local magnetic coordinates is used. This grid is generated by field-line tracing to guarantee an exact discretization of the dominant parallel transport (thus also minimizing the numerical diffusion problem). The perpendicular fluxes are then interpolated in a plane (a toroidal cut), where the interpolation problem for a quasi-isotropic system has to be solved by a constrained Delaunay triangulation (keeping the structural information for magnetic surfaces if they exist) and discretization. All toroidal terms are discretized by finite differences. Second, a Monte Carlo transport model originally developed for the modelling of the DED configuration of TEXTOR is used. A generalization and extension of this model was necessary to be able to handle W7-X. The model solves the transport equations with Monte Carlo techniques making use of mappings of local magnetic coordinates. The application of this technique to W7-X in a limiter-like configuration is presented. The decreasing dominance of parallel transport with respect to radial transport for electron heat, ion heat and particle transport results in increasingly steep profiles for the respective quantities within the islands. (author)

  17. Speckle dynamics under ergodicity breaking

    Science.gov (United States)

    Sdobnov, Anton; Bykov, Alexander; Molodij, Guillaume; Kalchenko, Vyacheslav; Jarvinen, Topias; Popov, Alexey; Kordas, Krisztian; Meglinski, Igor

    2018-04-01

    Laser speckle contrast imaging (LSCI) is a well-known and versatile approach for the non-invasive visualization of flows and microcirculation localized in turbid scattering media, including biological tissues. In most conventional implementations of LSCI the ergodic regime is typically assumed valid. However, most composite turbid scattering media, especially biological tissues, are non-ergodic, containing a mixture of dynamic and static centers of light scattering. In the current study, we examined the speckle contrast in different dynamic conditions with the aim of assessing limitations in the quantitative interpretation of speckle contrast images. Based on a simple phenomenological approach, we introduced a coefficient of speckle dynamics to quantitatively assess the ratio of the dynamic part of a scattering medium to the static one. The introduced coefficient allows one to distinguish real changes in motion from the mere appearance of static components in the field of view. As examples of systems with static/dynamic transitions, thawing and heating of Intralipid samples were studied by the LSCI approach.

  18. Ergodicity breakdown and scaling from single sequences

    Energy Technology Data Exchange (ETDEWEB)

    Kalashyan, Armen K. [Center for Nonlinear Science, University of North Texas, P.O. Box 311427, Denton, TX 76203-1427 (United States); Buiatti, Marco [Laboratoire de Neurophysique et Physiologie, CNRS UMR 8119 Universite Rene Descartes - Paris 5 45, rue des Saints Peres, 75270 Paris Cedex 06 (France); Cognitive Neuroimaging Unit - INSERM U562, Service Hospitalier Frederic Joliot, CEA/DRM/DSV, 4 Place du general Leclerc, 91401 Orsay Cedex (France); Grigolini, Paolo [Center for Nonlinear Science, University of North Texas, P.O. Box 311427, Denton, TX 76203-1427 (United States); Dipartimento di Fisica ' E.Fermi' - Universita di Pisa and INFM, Largo Pontecorvo 3, 56127 Pisa (Italy); Istituto dei Processi Chimico, Fisici del CNR Area della Ricerca di Pisa, Via G. Moruzzi 1, 56124 Pisa (Italy)], E-mail: grigo@df.unipi.it

    2009-01-30

    In the ergodic regime, several methods efficiently estimate the temporal scaling of time series characterized by long-range power-law correlations by converting them into diffusion processes. However, in the condition of ergodicity breakdown, the same methods give ambiguous results. We show that in such regime, two different scaling behaviors emerge depending on the age of the windows used for the estimation. We explain the ambiguity of the estimation methods by the different influence of the two scaling behaviors on each method. Our results suggest that aging drastically alters the scaling properties of non-ergodic processes.

  19. Ergodicity breakdown and scaling from single sequences

    International Nuclear Information System (INIS)

    Kalashyan, Armen K.; Buiatti, Marco; Grigolini, Paolo

    2009-01-01

    In the ergodic regime, several methods efficiently estimate the temporal scaling of time series characterized by long-range power-law correlations by converting them into diffusion processes. However, in the condition of ergodicity breakdown, the same methods give ambiguous results. We show that in such regime, two different scaling behaviors emerge depending on the age of the windows used for the estimation. We explain the ambiguity of the estimation methods by the different influence of the two scaling behaviors on each method. Our results suggest that aging drastically alters the scaling properties of non-ergodic processes.

  20. Ergodicity of the generalized lemon billiards

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jingyu [Department of Computer Science, University of Illinois at Urbana-Champaign, Champaign, Illinois 61801-2302 (United States); Mohr, Luke; Zhang, Hong-Kun, E-mail: hongkun@math.umass.edu; Zhang, Pengfei [Department of Mathematics and Statistics, UMass Amherst, Amherst, Massachusetts 01003 (United States)

    2013-12-15

    In this paper, we study a two-parameter family of convex billiard tables, by taking the intersection of two round disks (with different radii) in the plane. These tables give a generalization of the one-parameter family of lemon-shaped billiards. Initially, there is only one ergodic table among all lemon tables. In our generalized family, we observe numerically the prevalence of ergodicity among the some perturbations of that table. Moreover, numerical estimates of the mixing rate of the billiard dynamics on some ergodic tables are also provided.

  1. Lyapunov exponents and smooth ergodic theory

    CERN Document Server

    Barreira, Luis

    2001-01-01

    This book is a systematic introduction to smooth ergodic theory. The topics discussed include the general (abstract) theory of Lyapunov exponents and its applications to the stability theory of differential equations, stable manifold theory, absolute continuity, and the ergodic theory of dynamical systems with nonzero Lyapunov exponents (including geodesic flows). The authors consider several non-trivial examples of dynamical systems with nonzero Lyapunov exponents to illustrate some basic methods and ideas of the theory. This book is self-contained. The reader needs a basic knowledge of real analysis, measure theory, differential equations, and topology. The authors present basic concepts of smooth ergodic theory and provide complete proofs of the main results. They also state some more advanced results to give readers a broader view of smooth ergodic theory. This volume may be used by those nonexperts who wish to become familiar with the field.

  2. SUPRA SOFT SEPARATION AXIOMS AND SUPRA IRRESOLUTENESS BASED ON SUPRA B-SOFT SETS

    OpenAIRE

    Abd El-latif, Alaa Mohamed; Hosny, Rodyna Ahmed

    2016-01-01

    This paper introduces supra soft b-separation axioms based on the supra b-open soft sets which are more general than supra open soft sets. We investigate the relationships between these supra soft separation axioms. Furthermore, with the help of examples it is established that the converse does not hold. We show that, a supra soft topological space (X; t;E) is supra soft b-T1-space, if xE is supra b-closed soft set in for each x 2 X. Also, we prove that xE is supra b-closed soft set for each ...

  3. Plasma Surface interaction in Controlled fusion devices

    International Nuclear Information System (INIS)

    1990-05-01

    The subjects presented in the 9th conference on plasma surface interaction in controlled fusion devices were: the modifications of power scrape-off-length and power deposition during various configurations in Tore Supra plasmas; the effects observed in ergodic divertor experiments in Tore-Supra; the diffuse connexion induced by the ergodic divertor and the topology of the heat load patterns on the plasma facing components in Tore-Supra; the study of the influence of air exposure on graphite implanted by low energy high density deuterium plasma

  4. Supra-ballistic phonons

    International Nuclear Information System (INIS)

    Russell, F.M.

    1989-05-01

    Energetic particles moving with a solid, either from nuclear reactions or externally injected, deposit energy by inelastic scattering processes which eventually appears as thermal energy. If the transfer of energy occurs in a crystalline solid then it is possible to couple some of the energy directly to the nuclei forming the lattice by generating phonons. In this paper the transfer of energy from a compound excited nucleus to the lattice is examined by introducing a virtual particle Π. It is shown that by including a Π in the nuclear reaction a substantial amount of energy can be coupled directly to the lattice. In the lattice this particle behaves as a spatially localized phonon of high energy, the so-called supra-ballistic phonon. By multiple inelastic scattering the supra-ballistic phonon eventually thermalizes. Because both the virtual particle Π and the equivalent supra-ballistic phonon have no charge or spin and can only exist within a lattice it is difficult to detect other than by its decay into thermal phonons. The possibility of a Π removing excess energy from a compound nucleus formed by the cold fusion of deuterium is examined. (Author)

  5. Are atmospheric surface layer flows ergodic?

    Science.gov (United States)

    Higgins, Chad W.; Katul, Gabriel G.; Froidevaux, Martin; Simeonov, Valentin; Parlange, Marc B.

    2013-06-01

    The transposition of atmospheric turbulence statistics from the time domain, as conventionally sampled in field experiments, is explained by the so-called ergodic hypothesis. In micrometeorology, this hypothesis assumes that the time average of a measured flow variable represents an ensemble of independent realizations from similar meteorological states and boundary conditions. That is, the averaging duration must be sufficiently long to include a large number of independent realizations of the sampled flow variable so as to represent the ensemble. While the validity of the ergodic hypothesis for turbulence has been confirmed in laboratory experiments, and numerical simulations for idealized conditions, evidence for its validity in the atmospheric surface layer (ASL), especially for nonideal conditions, continues to defy experimental efforts. There is some urgency to make progress on this problem given the proliferation of tall tower scalar concentration networks aimed at constraining climate models yet are impacted by nonideal conditions at the land surface. Recent advancements in water vapor concentration lidar measurements that simultaneously sample spatial and temporal series in the ASL are used to investigate the validity of the ergodic hypothesis for the first time. It is shown that ergodicity is valid in a strict sense above uniform surfaces away from abrupt surface transitions. Surprisingly, ergodicity may be used to infer the ensemble concentration statistics of a composite grass-lake system using only water vapor concentration measurements collected above the sharp transition delineating the lake from the grass surface.

  6. On Supra-Additive and Supra-Multiplicative Maps

    OpenAIRE

    Jin Xi Chen; Zi Li Chen

    2013-01-01

    Let A and B be ordered algebras over ℝ, where A has a generating positive cone and B satisfies the property that b2>0 if 0≠b∈B. We give some conditions for a map T:A→B which is supra-additive and supra-multiplicative for all positive and negative elements to be linear and multiplicative; that is, T is a homomorphism of algebras. Our results generalize some known results on supra-additive and supra-multiplicative maps between spaces of real functions.

  7. Quantum ergodicity in the SYK model

    Science.gov (United States)

    Altland, Alexander; Bagrets, Dmitry

    2018-05-01

    We present a replica path integral approach describing the quantum chaotic dynamics of the SYK model at large time scales. The theory leads to the identification of non-ergodic collective modes which relax and eventually give way to an ergodic long time regime (describable by random matrix theory). These modes, which play a role conceptually similar to the diffusion modes of dirty metals, carry quantum numbers which we identify as the generators of the Clifford algebra: each of the 2N different products that can be formed from N Majorana operators defines one effective mode. The competition between a decay rate quickly growing in the order of the product and a density of modes exponentially growing in the same parameter explains the characteristics of the system's approach to the ergodic long time regime. We probe this dynamics through various spectral correlation functions and obtain favorable agreement with existing numerical data.

  8. Ergodic Theory, Open Dynamics, and Coherent Structures

    CERN Document Server

    Bose, Christopher; Froyland, Gary

    2014-01-01

    This book is comprised of selected research articles developed from a workshop on Ergodic Theory, Probabilistic Methods and Applications, held in April 2012 at the Banff International Research Station. It contains contributions from world leading experts in ergodic theory, dynamical systems, numerical analysis, fluid dynamics, and networks. The volume will serve as a valuable reference for mathematicians, physicists, engineers, physical oceanographers, atmospheric scientists, biologists, and climate scientists, who currently use, or wish to learn how to use, probabilistic techniques to cope with dynamical models that display open, coherent, or non-equilibrium behavior.

  9. Smooth Rényi Entropy of Ergodic Quantum Information Sources

    NARCIS (Netherlands)

    Schoenmakers, Berry; Tjoelker, Jilles; Tuyls, Pim; Verbitskiy, Evgeny

    2007-01-01

    We investigate the recently introduced notion of smooth Rényi entropy for the case of ergodic information sources, thereby generalizing previous work which concentrated mainly on i.i.d. information sources. We will actually consider ergodic quantum information sources, of which ergodic classical

  10. Smooth Rényi entropy of ergodic quantum information sources

    NARCIS (Netherlands)

    Schoenmakers, B.; Tjoelker, J.; Tuyls, P.T.; Verbitskiy, E.A.

    2007-01-01

    We investigate the recently introduced notion of smooth Rényi entropy for the case of ergodic information sources, thereby generalizing previous work which concentrated mainly on i.i.d. information sources. We will actually consider ergodic quantum information sources, of which ergodic classical

  11. Ergodicity of a single particle confined in a nanopore

    DEFF Research Database (Denmark)

    Bernardi, S.; Hansen, Jesper Schmidt; Frascolli, F.

    2012-01-01

    -ergodic component of the phase space for energy levels typical of experiments, is surprisingly small, i.e. we conclude that the ergodic hypothesis is a reasonable approximation even for a single particle trapped in a nanopore. Due to the numerical scope of this work, our focus will be the onset of ergodic behavior...

  12. Mixing, ergodicity and slow relaxation phenomena

    Science.gov (United States)

    Costa, I. V. L.; Vainstein, M. H.; Lapas, L. C.; Batista, A. A.; Oliveira, F. A.

    2006-11-01

    Investigations on diffusion in systems with memory [I.V.L. Costa, R. Morgado, M.V.B.T. Lima, F.A. Oliveira, Europhys. Lett. 63 (2003) 173] have established a hierarchical connection between mixing, ergodicity, and the fluctuation-dissipation theorem (FDT). This hierarchy means that ergodicity is a necessary condition for the validity of the FDT, and mixing is a necessary condition for ergodicity. In this work, we compare those results with recent investigations using the Lee recurrence relations method [M.H. Lee, Phys. Rev. B 26 (1982) 2547; M.H. Lee, Phys. Rev. Lett. 87 (2001) 250601; M.H. Lee, J. Phys. A: Math. Gen. 39 (2006) 4651]. Lee shows that ergodicity is violated in the dynamics of the electron gas [M.H. Lee, J. Phys. A: Math. Gen. 39 (2006) 4651]. This reinforces both works and implies that the results of [I.V.L. Costa, R. Morgado, M.V.B.T. Lima, F.A. Oliveira, Europhys. Lett. 63 (2003) 173] are more general than the framework in which they were obtained. Some applications to slow relaxation phenomena are discussed.

  13. Transitivity and ergodicity of quantum systems

    International Nuclear Information System (INIS)

    Narnhofer, H.; Thirring, W.; Wiklicky, H.

    1987-01-01

    First we try to generalize the notion of a topological transitive or a topologically mixing system for quantum mechanical systems in a consistent way. Furthermore we compare these ergodic properties with the classical results. Finaly we deal with some aspects of nearly abelian systems and investigate some relations between these notions. 11 refs. (Author)

  14. Combinatorial constructions in ergodic theory and dynamics

    CERN Document Server

    Katok, Anatole

    2003-01-01

    Ergodic theory studies measure-preserving transformations of measure spaces. These objects are intrinsically infinite and the notion of an individual point or an orbit makes no sense. Still there is a variety of situations when a measure-preserving transformation (and its asymptotic behavior) can be well described as a limit of certain finite objects (periodic processes). In the first part of this book this idea is developed systematically, genericity of approximation in various categories is explored, and numerous applications are presented, including spectral multiplicity and properties of the maximal spectral type. The second part of the book contains a treatment of various constructions of cohomological nature with an emphasis on obtaining interesting asymptotic behavior from approximate pictures at different time scales. The book presents a view of ergodic theory not found in other expository sources and is suitable for graduate students familiar with measure theory and basic functional analysis.

  15. Quantum ergodicity in a quantum measure algebra

    International Nuclear Information System (INIS)

    Stechel, E.B.

    1986-01-01

    This paper is divided into two parts. Part I assembles three pieces of background necessary to develop the logic behind this result. Section IA is devoted to classical algebraic ergodic theory (AET). Section IB briefly discusses random matrix theory (RMT) which should require very little development since a large fraction of this volume is devoted to this subject. Section IC reviews the concepts in quantum ''phase'' space flow (P(a,b)'s and p/sub n//sup a/'s). Part II develops what the authors will call quantum AET (the quantum analog of classical AET). Section IIA presents the formal development with the new definitions. Section IIB discusses intensity fluctuations in quantum ergodic (QE) spectra, leading to the somewhat surprising result that in a QE system a pure, real, smooth state samples only about 1/3 of its available space

  16. Morphodynamics: Ergodic theory of complex systems

    International Nuclear Information System (INIS)

    Fivaz, R.

    1993-01-01

    Morphodynamics is a general theory of stationary complex systems, such as living systems, or mental and social systems; it is based on the thermodynamics of physical systems and built on the same lines. By means of the ergodic hypothesis, thermodynamics is known to connect the particle dynamics to the emergence of order parameters in the equations of state. In the same way, morphodynamics connects order parameters to the emergence of higher level variables; through recurrent applications of the ergodic hypothesis, a hierarchy of equations of state is established which describes a series of successive levels of organization. The equations support a cognitivist interpretation that leads to general principles of evolution; the principles determine the spontaneous and irreversible complexification of systems living in their natural environment. 19 refs

  17. Ergodic Capacity for the SIMO Nakagami- Channel

    Directory of Open Access Journals (Sweden)

    Vagenas EfstathiosD

    2009-01-01

    Full Text Available This paper presents closed-form expressions for the ergodic channel capacity of SIMO (single-input and multiple output wireless systems operating in a Nakagami- fading channel. As the performance of SIMO channel is closely related to the diversity combining techniques, we present closed-form expressions for the capacity of maximal ratio combining (MRC, equal gain combining (EGC, selection combining (SC, and switch and stay (SSC diversity systems operating in Nakagami- fading channels. Also, the ergodic capacity of a SIMO system in a Nakagami- fading channel without any diversity technique is derived. The latter scenario is further investigated for a large amount of receive antennas. Finally, numerical results are presented for illustration.

  18. On Bitopological Supra B-Open Sets

    OpenAIRE

    M.Lellis Thivagar; B.Meera Devi

    2012-01-01

    In this paper, we introduce and investigate a new class of sets and maps be- tween bitopological spaces called supra(1,2) b-open, and supra (1,2) b-continuous maps, respectively. Furthermore, we introduce the concepts of supra(1,2) locally-closed, supra(1,2) locally b-closed sets. We also introduce supra(1,2) extremely disconnected. Finally, additional properties of these sets are investigated.

  19. Cryptanalysis of an ergodic chaotic cipher

    International Nuclear Information System (INIS)

    Alvarez, G.; Montoya, F.; Romera, M.; Pastor, G.

    2003-01-01

    In recent years, a growing number of cryptosystems based on chaos have been proposed, many of them fundamentally flawed by a lack of robustness and security. In this Letter, we offer our results after having studied the security and possible attacks on a very interesting cipher algorithm based on the logistic map's ergodicity property. This algorithm has become very popular recently, as it has been taken as the development basis of new chaotic cryptosystems

  20. An X-point ergodic divertor

    International Nuclear Information System (INIS)

    Chu, M.S.; Jensen, T.H.; La Haye, R.J.; Taylor, T.S.; Evans, T.E.

    1991-10-01

    A new ergodic divertor is proposed. It utilizes a system of external (n = 3) coils arranged to generate overlapping magnetic islands in the edge region of a diverted tokamak and connect the randomized field lines to the external (cold) divertor plate. The novel feature in the configuration is the placement of the external coils close to the X-point. A realistic design of the external coil set is studied by using the field line tracing method for a low aspect ratio (A ≅ 3) tokamak. Two types of effects are observed. First, by placing the coils close to the X-point, where the poloidal magnetic field is weak and the rational surfaces are closely packed only a moderate amount of current in the external coils is needed to ergodize the edge region. This ergodized edge enhances the edge transport in the X-point region and leads to the potential of edge profile control and the avoidance of edge localized modes (ELMs). Furthermore, the trajectories of the field lines close to the X-point are modified by the external coil set, causing the hit points on the external divertor plates to be randomized and spread out in the major radius direction. A time-dependent modulation of the currents in the external (n = 3) coils can potentially spread the heat flux more uniformly on the divertor plate avoiding high concentration of the heat flux. 10 refs., 9 figs

  1. Probability, random processes, and ergodic properties

    CERN Document Server

    Gray, Robert M

    1988-01-01

    This book has been written for several reasons, not all of which are academic. This material was for many years the first half of a book in progress on information and ergodic theory. The intent was and is to provide a reasonably self-contained advanced treatment of measure theory, prob ability theory, and the theory of discrete time random processes with an emphasis on general alphabets and on ergodic and stationary properties of random processes that might be neither ergodic nor stationary. The intended audience was mathematically inc1ined engineering graduate students and visiting scholars who had not had formal courses in measure theoretic probability . Much of the material is familiar stuff for mathematicians, but many of the topics and results have not previously appeared in books. The original project grew too large and the first part contained much that would likely bore mathematicians and dis courage them from the second part. Hence I finally followed the suggestion to separate the material and split...

  2. Coexistence of uniquely ergodic subsystems of interval mapping

    International Nuclear Information System (INIS)

    Ye Xiangdong.

    1991-10-01

    The purpose of this paper is to show that uniquely ergodic subsystems of interval mapping also coexist in the same way as minimal sets do. To do this we give some notations in section 2. In section 3 we define D-function of a uniquely ergodic system and show its basic properties. We prove the coexistence of uniquely ergodic subsystems of interval mapping in section 4. Lastly we give the examples of uniquely ergodic systems with given D-functions in section 5. 27 refs

  3. Spectroscopic measurements of the density and electronic temperature at the plasma edge in Tore Supra

    International Nuclear Information System (INIS)

    Lediankine, A.

    1996-01-01

    The profiles of temperature and electronic density at the plasma edge are important to study the wall-plasma interaction and the radiative layers in the Tokamak plasmas. The laser ablation technique of the lithium allows to measure the profile of electronic density. To measure the profile of temperature, it has been used for the first time, the injection of a fluorine neutral atoms beam. The experiments, the results are described in this work. (N.C.)

  4. Experiments on steady state particle control in Tore Supra and DIII-D

    International Nuclear Information System (INIS)

    Mioduszewski, P.K.; Hogan, J.T.; Owen, L.W.; Maingi, R.; Lee, D.K.; Hillis, D.L.; Klepper, C.C.; Menon, M.M.; Thomas, C.E.; Uckan, T.; Wade, M.R.; Chatelier, M.; Grisolia, C.; Ghendrih, P.; Grosman, A.; Hutter, T.; Loarer, T.; Pegourie, B.; Mahdavi, M.A.; Schaffer, M.

    1995-01-01

    Particle control is playing an increasingly important role in tokamak plasma performance. The present paper discusses particle control of hydogen/deuterium by wall pumping on graphite or carbonized surfaces, as well as by external exhaust with pumped limiters and pumped divertors. Wall pumping is ultimately a transient effect and by itself not suitable for steady state particle exhaust. Therefore, external exhaust techniques with pumped divertors and limiters are being developed. How wall pumping phenomena interact and correlate with these inherently steady state, external exhaust techniques, is not well known to date. In the present paper, the processes involved in wall pumping and in external pumping are investigated in an attempt to evaluate the effect of external exhaust on wall pumping. Some of the key elements of this analysis are: (1) charge-exchange fluxes to the wall play a crucial role in the core-wall particle dynamics, (2) the recycling fluxes of thermal molecules have a high probability of ionization in the scrape-off layer, (3) thermal particles originating from the wall, which are ionized within the scrape-off layer, can be directly exhausted, thus providing a direct path between wall and exhaust which can be used to control the wall inventory. This way, the wall can be kept in a continuous pumping state in the sense that it continuously absorbs energetic particles and releases thermal molecules which are then removed by the external exhaust mechanism. While most of the ingredients of this analysis have been observed individually before, the present evaluation is an attempt to correlate effects of wall recycling and external exhaust. ((orig.))

  5. Scrape-off layer power flux measurements in the Tore Supra tokamak

    Czech Academy of Sciences Publication Activity Database

    Gunn, J. P.; Dejarnac, Renaud; Devynck, P.; Fedorczak, N.; Fuchs, Vladimír; Gil, C.; Kočan, M.; Komm, Michael; Kubič, M.; Lunt, T.; Monier-Garbet, P.; Pascal, J.-Y.; Saint-Laurent, F.

    2013-01-01

    Roč. 438, suppl (2013), S184-S188 ISSN 0022-3115. [International Conference on Plasma-Surface Interactions in Controlled Fusion Devices/20./. Aachen, 21.05.2012-25.05.2012] Institutional support: RVO:61389021 Keywords : plasma * tokamak Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.016, year: 2013 http://www.sciencedirect.com/science/article/pii/S0022311513000639#

  6. Observation of a new plasma regime with stationary electron temperature oscillations on Tore Supra

    International Nuclear Information System (INIS)

    Artaud, J.F.; Giruzzi, G.; Imbeaux, F.; Segui, J.L.; Garbet, X.

    2003-01-01

    This document is a copy of the slides presented on the 9. joint US-European Transport Task Force meeting. The first part is devoted to the experimental observations of a new tokamak plasma regime with stationary electron temperature oscillations. The oscillations appear on ECE spontaneously, sometimes associated with a transition to the LHEP regime. The second part presents an interpretation of these oscillations by analogy with a predator-prey system. (A.L.B.)

  7. Experimental Investigation of Nonlinear Coupling of Lower Hybrid Waves on Tore Supra

    Czech Academy of Sciences Publication Activity Database

    Goniche, M.; Frincu, B.; Ekedahl, A.; Petržílka, Václav; Berger-By, G.; Hillairet, J.; Litaudon, X.; Preynas, M.; Voyer, D.

    2012-01-01

    Roč. 62, č. 2 (2012), s. 322-332 ISSN 1536-1055 R&D Projects: GA ČR GA202/07/0044 Institutional research plan: CEZ:AV0Z20430508 Keywords : LHwave * plasma * lower hybrid * wave coupling * nonlinear coupling Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.517, year: 2012

  8. The Tore Supra toroidal pump limiter: experience feedback of HHF elements series manufacture

    Energy Technology Data Exchange (ETDEWEB)

    Cordier, J.J.; Bayetti, P.; Chappuis, P.; Durocher, A.; Escourbiac, F.; Grosman, A.; Lipa, M.; Mitteau, R.; Schlosser, J.; Van Houtte, D

    2003-07-01

    Since 1992, reliable High Heat Flux PFCs based on copper alloy heat sink structures and a CFC armour, have been developed. The final result is an actively cooled high heat flux element that is capable of removing up to 10 MW.m{sup -2} in stationary operating conditions. About 600 of these high performance individual components have then been manufactured and assembled in order to equip a Toroidal Pump Limiter (TPL). The final deliveries was successfully achieved end of 2001. The paper deals with the experience feedback built-up along the four years duration of the TPL components manufacture. We will show where issues were encountered, how solutions were found to achieve the fabrication of components and will highlight what are the main technical lessons to be learned: acceptance criteria, choice of materials, margins of processes. Finally a proposal of an alternative optimised design is presented, fruit of the experience gained from this up to now, unique series manufacture of actively cooled plasma facing HHF components. We believe that such experience will certainly be of use to ITER as well as to Wendelstein 7-X as far as PFC is concerned. (authors)

  9. Stationary magnetic shear reversal during Lower Hybrid experiments in Tore Supra

    International Nuclear Information System (INIS)

    Litaudon, X.; Arslanbekov, R.; Hoang, G.T.; Joffrin, E.; Kazarian-Vibert, F.; Moreau, D.; Peysson, Y.; Bibet, P.

    1996-01-01

    Stable and stationary states with hollow current density profiles have been achieved with Lower Hybrid Current Drive (LHCD) during Lower Hybrid (LH) wave accessibility experiments. By analysing the bounded propagation domain in phase space which naturally limits the central penetration and absorption of the waves, off-axis LH power deposition has been realized in a reproducible manner. The resulting current density profile modifications have led to a global confinement enhancement attributed to the formation of an internal 'transport barrier' in the central reversed shear region where the electron thermal diffusivity is reduced to its neoclassical collisional level. The multiple-pass LH wave propagation in the weak Landau damping and reversed magnetic shear regime is also investigated in the framework of a statistical theory and the experimental validation of this theory is discussed. (author)

  10. Theory and experiments on RF plasma heating, current drive and profile control in TORE SUPRA

    International Nuclear Information System (INIS)

    Moreau, D.

    1994-01-01

    This paper reviews the main experimental and theoretical achievements related to the study of RF heating and non-inductive current drive and particularly phenomena related to the current density profile control and the potentiality of producing stationary enhanced performance regimes: description of the Lower Hybrid (LH) and Ion Cyclotron Resonant Frequency (ICRF) systems; long pulse coupling performance of the RF systems; observation of the transition to the so-called ''stationary LHEP regime'' in which the (flat) central current density and (peaked) electron temperature profiles are fully decoupled; experiments on ICRF sawtooth stabilization with the combined effect of LHCD modifying the current density profile; diffusion of fast electrons generated by LH waves; ramp-up experiments in which the LH power provided a significant part of the resistive poloidal flux and flux consumption scaling; theory of spectral wave diffusion and multipass absorption; fast wave current drive modelling with the Alcyon full wave code; a reflector LH antenna concept. 18 figs., 48 refs

  11. Measurement of lower hybrid hot spots using a retarding field analyzer in Tore Supra

    Czech Academy of Sciences Publication Activity Database

    Gunn, J. P.; Petržílka, Václav; Ekedahl, A.; Fuchs, Vladimír; Gauthier, E.; Goniche, M.; Kočan, M.; Pascal, J.Y.; Saint Laurent, F.

    390-391, č. 1 (2009), s. 904-906 ISSN 0022-3115. [International Conference on Plasma-Surface Interactions in Controlled Fusion Devices/18th./. Toledo, 26.05.2008-30.5.2008] R&D Projects: GA ČR GA202/07/0044 Institutional research plan: CEZ:AV0Z20430508 Keywords : Lower Hybrid * hot spots * ELECTRONS * POWER Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.933, year: 2009 http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TXN-4VG7MW6-7&_user=6542793&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_acct=C000070123&_version=1&_urlVersion=0&_userid=6542793&md5=944ed4d95df86a149fa36439db6215db

  12. Tore Supra: a tokamak with superconducting coils for the toroidal field

    International Nuclear Information System (INIS)

    Turck, B.

    1984-01-01

    It is under construction on the site of CEN/Cadarache for the EURATOM-CEA Association. The design has been lead by a group including teams of the DRFC of Fontenay-aux-Roses and Grenoble and the DPh/PE-STI of CEN/Saclay [fr

  13. Thermal and non-thermal particle interaction with the LHCD launchers in Tore Supra

    Czech Academy of Sciences Publication Activity Database

    Ekedahl, A.; Goniche, M.; Balorin, C.; Basiuk, V.; Bibet, Ph.; Chantant, M.; Colas, L.; Delpech, L.; Desgranges, C.; Eriksson, L.-G.; Joffrin, E.; Kazarian, F.; Lowry, C.; Moreau, Ph.; Petržílka, Václav; Portafaix, C.; Prou, M.; Roche, H.

    363-365, č. 8 (2007), s. 1329-1333 ISSN 0022-3115 R&D Projects: GA ČR(CZ) GA202/07/0044 Institutional research plan: CEZ:AV0Z20430508 Keywords : LH grill * plasma Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.643, year: 2007

  14. Parallel expansion of the ablation cloud during pellet injection in Tore Supra

    International Nuclear Information System (INIS)

    Pegourie, B.; Bruneau, J.L.; Picchiottino, J.M.

    1991-01-01

    The ablated matter propagation along the field lines during pellet ablation is observed with a five chords interferometer toroidally located at -π/3 of the pellet injector. The time resolution is 16μs and the sensitivity better than 3 10 17 m -2 . The beginning of the fast acquisition is triggered by the pellet itself and its maximum duration is 20ms. About 500μs after the pellet enters the discharge, the experimental signals exhibit a steep increase. Excepted in a few cases for which a strong oscillation at a typical frequency of 0.5kHz was detected during several ms, a new quasi-steady state is reached after about lms. The importance of the measured perturbation and the details of the sequence described above depends, for each chord, on both the Q profile and pellet penetration

  15. Investigation of steady-state tokamak issues by long pulse experiments on Tore Supra

    Czech Academy of Sciences Publication Activity Database

    Giruzzi, G.; Abgrall, R.; Allegretti, L.; Ané, J.M.; Angelino, P.; Aniel, T.; Argouarch, A.; Artaud, J.F.; Balme, S.; Basiuk, V.; Bayetti, P.; Bécoulet, A.; Bécoulet, M.; Begrambekov, L.; Benkadda, M.S.; Benoit, F.; Berger-by, G.; Bertrand, B.; Beyer, P.; Blum, J.; Boilson, D.; Bottollier-Curtet, H.; Bouchand, C.; Bouquey, F.; Bourdelle, C.; Brémond, F.; Brémond, S.; Brosset, C.; Bucalossi, J.; Buravand, Y.; Cara, P.; Carpentier, S.; Casati, A.; Chaibi, O.; Chantant, M.; Chappuis, P.; Chatelier, M.; Chevet, G.; Ciazynski, D.; Ciraolo, G.; Clairet, F.; Clary, J.; Colas, L.; Corre, Y.; Courtois, X.; Crouseilles, N.; Darmet, G.; Davi, M.; Daviot, R.; De Esch, H.; Decker, J.; Decool, P.; Delchambre, E.; Delmas, E.; Delpech, L.; Desgranges, C.; Devynck, P.; Doceul, L.; Dolgetta, N.; Douai, D.; Dougnac, H.; Duchateau, J.L.; Dumont, R.; Dunand, A.; Durocher, A.; Ekedahl, A.; Elbeze, D.; Eriksson, L.G.; Escarguel, A.; Escourbiac, F.; Faisse, F.; Falchetto, G.; Farge, M.; Farjon, L.J.; Fedorczak, N.; Fenzi-Bonizec, C.; Garbet, X.; Garcia, J.; Gardarein, J.L.; Gargiulo, L.; Garibaldi, P.; Gauthier, E.; Géraud, A.; Gerbaud, T.; Geynet, M.; Ghendrih, P.; Gil, C.; Goniche, M.; Grandgirard, V.; Grisolia, C.; Gros, G.; Grosman, A.; Guigon, R.; Guilhem, D.; Guillerminet, B.; Guirlet, R.; Gunn, J.; Hacquin, S.; Hatchressian, J.C.; Hennequin, P.; Henry, D.; Hernandez, C.; Hertout, P.; Heuraux, S.; Hillairet, J.; Hoang, G.T.; Hong, S.H.; Honore, C.; Hourtoule, J.; Houry, M.; Hutter, T.; Huynh, P.; Huysmans, G.; Imbeaux, F.; Joffrin, E.; Johner, J.; Journeaux, J.Y.; Jullien, F.; Kazarian, F.; Kočan, M.; Lacroix, B.; Lamaison, V.; Lasalle, J.; Latu, G.; Lausenaz, Y.; Laviron, C.; Le Niliot, C.; Lennholm, M.; Leroux, F.; Linez, F.; Lipa, M.; Litaudon, X.; Loarer, T.; Lott, F.; Lotte, P.; Luciani, J.F.; Lütjens, H.; Macor, A.; Madeleine, S.; Magaud, P.; Maget, P.; Magne, R.; Manenc, L.; Marandet, Y.; Marbach, G.; Maréchal, J.L.; Martin, C.; Martin, V.; Martinez, A.; Martins, J.P.; Masset, R.; Mazon, D.; Meunier, L.; Meyer, O.; Million, L.; Missirlian, M.; Mitteau, R.; Mollard, P.; Moncada, V.; Monier-Garbet, P.; Moreau, D.; Moreau, P.; Nannini, M.; Nardon, E.; Nehme, H.; Nguyen, C.; Nicollet, S.; Ottaviani, M.; Pacella, D.; Pamela, S.; Parisot, P.; Parrat, H.; Pastor, P.; Pecquet, A.L.; Pégourié, B.; Petržílka, Václav; Peysson, Y.; Portafaix, C.; Prou, M.; Ravenel, N.; Reichle, R.; Reux, C.; Reynaud, P.; Richou, M.; Rigollet, F.; Rimini, F.; Roche, H.; Rosanvallon, S.; Roth, J.; Roubin, P.; Sabot, R.; Saint-Laurent, F.; Salasca, S.; Salmon, T.; Samaille, F.; Santagiustina, A.; Saoutic, B.; Sarazin, Y.; Schlosser, J.; Schneider, K.; Schneider, M.; Schwander, F.; Ségui, J.L.; Signoret, J.; Simonin, A.; Song, S.; Sonnendruker, E.; Spuig, P.; Svensson, L.; Tamain, P.; Tena, M.; Theis, J.M.; Thonnat, M.; Torre, A.; Travère, J.M.; Trier, E.; Tsitrone, E.; Turco, F.; Vallet, J.C.; Vatry, A.; Vermare, L.; Villecroze, F.; Villegas, D.; Voyer, D.; Vulliez, K.; Xiao, W.; Yu, D.; Zani, L.; Zou, X.L.; Zwingmann, W.

    2009-01-01

    Roč. 49, č. 10 (2009), s. 104010-104010 ISSN 0029-5515 Institutional research plan: CEZ:AV0Z20430508 Keywords : SOL * LH wave * plasma Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 4.270, year: 2009 http://www.iop.org/EJ/toc/0029-5515/49/10

  16. Design of a four-channel bolometer module for ASDEX upgrade and tore supra

    International Nuclear Information System (INIS)

    Mueller, E.R.; Weber, G.; Mast, F.; Schramm, G.; Buchelt, E.; Andelfinger, C.

    1985-10-01

    A new small-sized four-bolometer module for application in high-temperature plasma diagnostics has been designed. The four bolometers and the four reference bolometers shielded against radiation are placed side by side on one kapton foil, the entire arrangement occupying an area of 2.0x3.3 cm 2 . The central part of each bolometer consists of a 1.5x4 mm 2 large, 4 to 15 μm thick radiation absorber made of gold, a 7.5 μm thick kapton carrier foil, and a 0.05 μm thick meander-like gold resistor (conduction path width: 30 μm). It offers all the advantages already provided by the well-known ASDEX and JET bolometers, such as very high operating reliability and resistance to nuclear radiation damage. It is optional to enlarge the cooling time constant of the bolometer in a controlled way from a few milliseconds up to several hundreds, thus improving the sensitivity to very weak signals in the low-frequency (<=20 Hz) part of the radiation spectrum, by means of an additional (thin) gold layer that delays the heat losses from the bolometer foil to the cooling body. Since the bolometer is very suitable for AC-bridge electronics and all bridge resistors are arranged on a minimum area interference signals should be suppressed to extremely low levels. (orig.)

  17. Association Contributions to the 21th EPS Conference

    International Nuclear Information System (INIS)

    1995-01-01

    A wide range of topics concerning plasma physics at Tore Supra tokamak device is covered. Different ways of plasma heating, such as current drive, electron and ion cyclotron-resonance heating and lower hybrid heating, plasma confinement, different topics on transport theory and plasma diagnostics are discussed. The new ergodic divertor at Tore Supra is studied from different aspects. 35 items have been separately indexed for the INIS database. (K.A.)

  18. Quantum ergodicity and a quantum measure algebra

    International Nuclear Information System (INIS)

    Stechel, E.B.

    1985-01-01

    A quantum ergodic theory for finite systems (such as isolated molecules) is developed by introducing the concept of a quantum measure algebra. The basic concept in classical ergodic theory is that of a measure space. A measure space is a set M, together with a specified sigma algebra of subsets in M and a measure defined on that algebra. A sigma algebra is closed under the formation of intersections and symmetric differences. A measure is a nonnegative and countably additive set function. For this to be further classified as a dynamical system, a measurable transformation is introduced. A measurable transformation is a mapping from a measure space into a measure space, such that the inverse image of every measurable set is measurable. In conservative dynamical systems, a measurable transformation is measure preserving, which is to say that the inverse image of every measurable set has the same measure as the original set. Once the measure space and the measurable transformation are defined, ergodic theory can be investigated on three levels: describable as analytic, geometric and algebraic. The analytic level studies linear operators induced by a transformation. The geometric level is concerned directly with transformations on a measure space and the algebraic treatments substitute a measure algebra for the measure space and basically equate sets that differ only by sets of measure zero. It is this latter approach that is most directly paralleled here. A measure algebra for a quantum dynamical system is defined within which stochastic concepts in quantum mechanics can be investigated. The quantum measure algebra differs from a normal measure algebra only in that multiplication is noncommutative and addition is nonassociative. Nonetheless, the quantum measure algebra preserves the essence of a normal measure algebra

  19. Ergodic Properties of the Quantum Geodesic Flow on Tori

    Energy Technology Data Exchange (ETDEWEB)

    Klimek, SLawomir [Indiana University Purdue University Indianapolis, Department of Mathematics (United States); Kondracki, Witold [Polish Academy of Sciences, Institute of Mathematics (Poland)

    2005-05-15

    We study ergodic averages for a class of pseudo-differential operators on the flat N-dimensional torus with respect to the Schroedinger evolution. The later can be consider a quantization of the geodesic flow on T{sup N}. We prove that, up to semi-classically negligible corrections, such ergodic averages are translationally invariant operators.

  20. Strong ergodic theorem for commutative semigroup of non ...

    Indian Academy of Sciences (India)

    M Azhini

    2017-08-14

    Aug 14, 2017 ... of non-Lipschitzian mappings in multi-Banach space ... to studying nonlinear ergodic theory for (asymptotically) non-expansive ... As we know, Bruck's lemmas are essential tools in the proof of almost all mean ergodic theorem ...

  1. Avoiding ergodicity and turbulence in R3 vector fields

    International Nuclear Information System (INIS)

    Ancochea, J.M.; Campoamor-Stursberg, R.; Gonzalez-Gascon, F.

    2003-01-01

    We show that analytic R 3 vector fields having the property of being transversal to either analytic functions or foliations F 2 , or parallel to a foliation, are free from ergodicity and turbulence. The absence of turbulence and ergodicity via induced vector fields is also proven

  2. Generalized continued fractions and ergodic theory

    International Nuclear Information System (INIS)

    Pustyl'nikov, L D

    2003-01-01

    In this paper a new theory of generalized continued fractions is constructed and applied to numbers, multidimensional vectors belonging to a real space, and infinite-dimensional vectors with integral coordinates. The theory is based on a concept generalizing the procedure for constructing the classical continued fractions and substantially using ergodic theory. One of the versions of the theory is related to differential equations. In the finite-dimensional case the constructions thus introduced are used to solve problems posed by Weyl in analysis and number theory concerning estimates of trigonometric sums and of the remainder in the distribution law for the fractional parts of the values of a polynomial, and also the problem of characterizing algebraic and transcendental numbers with the use of generalized continued fractions. Infinite-dimensional generalized continued fractions are applied to estimate sums of Legendre symbols and to obtain new results in the classical problem of the distribution of quadratic residues and non-residues modulo a prime. In the course of constructing these continued fractions, an investigation is carried out of the ergodic properties of a class of infinite-dimensional dynamical systems which are also of independent interest

  3. Monotone measures of ergodicity for Markov chains

    Directory of Open Access Journals (Sweden)

    J. Keilson

    1998-01-01

    Full Text Available The following paper, first written in 1974, was never published other than as part of an internal research series. Its lack of publication is unrelated to the merits of the paper and the paper is of current importance by virtue of its relation to the relaxation time. A systematic discussion is provided of the approach of a finite Markov chain to ergodicity by proving the monotonicity of an important set of norms, each measures of egodicity, whether or not time reversibility is present. The paper is of particular interest because the discussion of the relaxation time of a finite Markov chain [2] has only been clean for time reversible chains, a small subset of the chains of interest. This restriction is not present here. Indeed, a new relaxation time quoted quantifies the relaxation time for all finite ergodic chains (cf. the discussion of Q1(t below Equation (1.7]. This relaxation time was developed by Keilson with A. Roy in his thesis [6], yet to be published.

  4. SUPRA - Enhanced upset recovery simulation

    NARCIS (Netherlands)

    Groen, E.; Ledegang, W.; Field, J.; Smaili, H.; Roza, M.; Fucke, L.; Nooij, S.; Goman, M.; Mayrhofer, M.; Zaichik, L.E.; Grigoryev, M.; Biryukov, V.

    2012-01-01

    The SUPRA research project - Simulation of Upset Recovery in Aviation - has been funded by the European Union 7th Framework Program to enhance the flight simulation envelope for upset recovery simulation. Within the project an extended aerodynamic model, capturing the key aerodynamics during and

  5. Broken ergodicity in two-dimensional homogeneous magnetohydrodynamic turbulence

    International Nuclear Information System (INIS)

    Shebalin, John V.

    2010-01-01

    Two-dimensional (2D) homogeneous magnetohydrodynamic (MHD) turbulence has many of the same qualitative features as three-dimensional (3D) homogeneous MHD turbulence. These features include several ideal (i.e., nondissipative) invariants along with the phenomenon of broken ergodicity (defined as nonergodic behavior over a very long time). Broken ergodicity appears when certain modes act like random variables with mean values that are large compared to their standard deviations, indicating a coherent structure or dynamo. Recently, the origin of broken ergodicity in 3D MHD turbulence that is manifest in the lowest wavenumbers was found. Here, we study the origin of broken ergodicity in 2D MHD turbulence. It will be seen that broken ergodicity in ideal 2D MHD turbulence can be manifest in the lowest wavenumbers of a finite numerical model for certain initial conditions or in the highest wavenumbers for another set of initial conditions. The origins of broken ergodicity in an ideal 2D homogeneous MHD turbulence are found through an eigenanalysis of the covariance matrices of the probability density function and by an examination of the associated entropy functional. When the values of ideal invariants are kept fixed and grid size increases, it will be shown that the energy in a few large modes remains constant, while the energy in any other mode is inversely proportional to grid size. Also, as grid size increases, we find that broken ergodicity becomes manifest at more and more wavenumbers.

  6. Ergodic directional switching in mobile insect groups

    KAUST Repository

    Escudero, Carlos; Yates, Christian A.; Buhl, Jerome; Couzin, Iain D.; Erban, Radek; Kevrekidis, Ioannis G.; Maini, Philip K.

    2010-01-01

    We obtain a Fokker-Planck equation describing experimental data on the collective motion of locusts. The noise is of internal origin and due to the discrete character and finite number of constituents of the swarm. The stationary probability distribution shows a rich phenomenology including nonmonotonic behavior of several order and disorder transition indicators in noise intensity. This complex behavior arises naturally as a result of the randomness in the system. Its counterintuitive character challenges standard interpretations of noise induced transitions and calls for an extension of this theory in order to capture the behavior of certain classes of biologically motivated models. Our results suggest that the collective switches of the group's direction of motion might be due to a random ergodic effect and, as such, they are inherent to group formation. © 2010 The American Physical Society.

  7. Ergodic directional switching in mobile insect groups

    KAUST Repository

    Escudero, Carlos

    2010-07-29

    We obtain a Fokker-Planck equation describing experimental data on the collective motion of locusts. The noise is of internal origin and due to the discrete character and finite number of constituents of the swarm. The stationary probability distribution shows a rich phenomenology including nonmonotonic behavior of several order and disorder transition indicators in noise intensity. This complex behavior arises naturally as a result of the randomness in the system. Its counterintuitive character challenges standard interpretations of noise induced transitions and calls for an extension of this theory in order to capture the behavior of certain classes of biologically motivated models. Our results suggest that the collective switches of the group\\'s direction of motion might be due to a random ergodic effect and, as such, they are inherent to group formation. © 2010 The American Physical Society.

  8. An Almost Sure Ergodic Theorem for Quasistatic Dynamical Systems

    International Nuclear Information System (INIS)

    Stenlund, Mikko

    2016-01-01

    We prove an almost sure ergodic theorem for abstract quasistatic dynamical systems, as an attempt of taking steps toward an ergodic theory of such systems. The result at issue is meant to serve as a working counterpart of Birkhoff’s ergodic theorem which fails in the quasistatic setup. It is formulated so that the conditions, which essentially require sufficiently good memory-loss properties, could be verified in a straightforward way in physical applications. We also introduce the concept of a physical family of measures for a quasistatic dynamical system. These objects manifest themselves, for instance, in numerical experiments. We then illustrate the use of the theorem by examples.

  9. An Almost Sure Ergodic Theorem for Quasistatic Dynamical Systems

    Energy Technology Data Exchange (ETDEWEB)

    Stenlund, Mikko, E-mail: mikko.stenlund@helsinki.fi [University of Helsinki, Department of Mathematics and Statistics (Finland)

    2016-09-15

    We prove an almost sure ergodic theorem for abstract quasistatic dynamical systems, as an attempt of taking steps toward an ergodic theory of such systems. The result at issue is meant to serve as a working counterpart of Birkhoff’s ergodic theorem which fails in the quasistatic setup. It is formulated so that the conditions, which essentially require sufficiently good memory-loss properties, could be verified in a straightforward way in physical applications. We also introduce the concept of a physical family of measures for a quasistatic dynamical system. These objects manifest themselves, for instance, in numerical experiments. We then illustrate the use of the theorem by examples.

  10. First results from the dynamic ergodic divertor at TEXTOR

    International Nuclear Information System (INIS)

    Lehnen, M.; Abdullaev, S.S.; Biel, W.; Brezinsek, S.; Finken, K.H.; Harting, D.; Hellermann, M. von; Jakubowski, M.; Jaspers, R.; Kobayashi, M.; Koslowski, H.R.; Kraemer-Flecken, A.; Matsunaga, G.; Pospieszczyk, A.; Reiter, D.; Van Rompuy, T.; Samm, U.; Schmitz, O.; Sergienko, G.; Unterberg, B.; Wolf, R.; Zimmermann, O.

    2005-01-01

    Experimental results from the dynamic ergodic divertor (DED) at TEXTOR are given, describing the complex structure of the edge plasma and the properties of the divertor as well as its influence on the plasma rotation

  11. The accuracy of time dependent transport equation ergodic approximation

    International Nuclear Information System (INIS)

    Stancic, V.

    1995-01-01

    In order to predict the accuracy of the ergodic approximation for solving the time dependent transport equation, a comparison with respect to multiple collision and time finite difference methods, has been considered. (author)

  12. The average-shadowing property and topological ergodicity for flows

    International Nuclear Information System (INIS)

    Gu Rongbao; Guo Wenjing

    2005-01-01

    In this paper, the transitive property for a flow without sensitive dependence on initial conditions is studied and it is shown that a Lyapunov stable flow with the average-shadowing property on a compact metric space is topologically ergodic

  13. Non-ergodicity of Nosé–Hoover dynamics

    International Nuclear Information System (INIS)

    Legoll, Frédéric; Luskin, Mitchell; Moeckel, Richard

    2009-01-01

    The Nosé–Hoover dynamics is a deterministic method that is commonly used to sample the canonical Gibbs measure. This dynamics extends the physical Hamiltonian dynamics by the addition of a 'thermostat' variable, which is coupled nonlinearly with the physical variables. The accuracy of the method depends on the dynamics being ergodic. Numerical experiments have been published earlier that are consistent with non-ergodicity of the dynamics for some model problems. The authors recently proved the non-ergodicity of the Nosé–Hoover dynamics for the one-dimensional harmonic oscillator. In this paper, this result is extended to non-harmonic one-dimensional systems. We also show that, for some multidimensional systems, the averaged dynamics for the limit of infinite thermostat 'mass' has many invariants, thus giving theoretical support for either non-ergodicity or slow ergodization. Numerical experiments for a two-dimensional central force problem and the one-dimensional pendulum problem give evidence for non-ergodicity

  14. On Neutrosophic Semi-Supra Open Set and Neutrosophic Semi-Supra Continuous Functions

    OpenAIRE

    R. Dhavaseelan; M. Parimala; S. Jafari; F. Smarandache

    2017-01-01

    In this paper, we introduce and investigate a new class of sets and functions between topological space called neutrosophic semi-supra open set and neutrosophic semi-supra open continuous functions respectively.

  15. EURATOM-CEA association contributions to the 18. IAEA fusion energy conference

    Energy Technology Data Exchange (ETDEWEB)

    Ghendrih, Ph.; Peysson, Y.; Hoang, G.T. [and others

    2000-12-01

    The 9 contributions of EURATOM-Cea association to the fusion energy conference hold at Sorrento are gathered in this document with 7 additional papers. The different titles are: 1) Ergodic divertor experiments on the route to steady state operation of Tore-Supra, 2) High power lower hybrid current drive experiments in Tore-Supra tokamak, 3) Electron transport and improved confinement on Tore-Supra, 4) ECRH experiments and developments for long pulse in Tore-Supra, 5) Impurity penetration and contamination in Tore-Supra ergodic divertor experiments, 6) Real time plasma feed-back control: an overview of Tore-Supra achievements, 7) Numerical assessment of the ion turbulent thermal transport scaling laws, 8) Design of next step tokamak: consistent analysis of plasma flux consumption and poloidal, 9) Large superconducting conductors and joints for fusion magnets: from conceptual design to test at full size scale, 10) Burst-prone transport in tokamaks with internal transport barriers, 11) Electrostatic turbulence with finite parallel correlation length and radial electric field generation, 12) Theoretical issues in tokamak confinement: internal-edge transport barriers and runaway avalanche confinement, 13) Core and edge confinement studies with different heating methods in JET, 14) Confinement and transport studies of conventional scenarios in ASDEX upgrade, 15) First test results for the ITER central solenoid model coil, and 16) Progress of the ITER central solenoid model coil program.

  16. EURATOM-CEA association contributions to the 18. IAEA fusion energy conference

    International Nuclear Information System (INIS)

    Ghendrih, Ph.; Peysson, Y.; Hoang, G.T.

    2000-12-01

    The 9 contributions of EURATOM-Cea association to the fusion energy conference hold at Sorrento are gathered in this document with 7 additional papers. The different titles are: 1) Ergodic divertor experiments on the route to steady state operation of Tore-Supra, 2) High power lower hybrid current drive experiments in Tore-Supra tokamak, 3) Electron transport and improved confinement on Tore-Supra, 4) ECRH experiments and developments for long pulse in Tore-Supra, 5) Impurity penetration and contamination in Tore-Supra ergodic divertor experiments, 6) Real time plasma feed-back control: an overview of Tore-Supra achievements, 7) Numerical assessment of the ion turbulent thermal transport scaling laws, 8) Design of next step tokamak: consistent analysis of plasma flux consumption and poloidal, 9) Large superconducting conductors and joints for fusion magnets: from conceptual design to test at full size scale, 10) Burst-prone transport in tokamaks with internal transport barriers, 11) Electrostatic turbulence with finite parallel correlation length and radial electric field generation, 12) Theoretical issues in tokamak confinement: internal-edge transport barriers and runaway avalanche confinement, 13) Core and edge confinement studies with different heating methods in JET, 14) Confinement and transport studies of conventional scenarios in ASDEX upgrade, 15) First test results for the ITER central solenoid model coil, and 16) Progress of the ITER central solenoid model coil program

  17. On Some Maps in Supra Topological Ordered Spaces

    OpenAIRE

    Al-shami, Tareq Mohammed

    2018-01-01

    In [6] the notion of supra semi open sets was presented and some of its properties were discussed. In this study, we introduce and investigate four main concepts namely supra continuous (supra open, supra closed, supra homeomorphism) maps via supra topological ordered spaces. Our findings in this work generalize some previous results in ([1], [13]). Many examples are considered to show the concepts introduced and main results obtained herein.

  18. Quantum Ergodicity and L p Norms of Restrictions of Eigenfunctions

    Science.gov (United States)

    Hezari, Hamid

    2018-02-01

    We prove an analogue of Sogge's local L p estimates for L p norms of restrictions of eigenfunctions to submanifolds, and use it to show that for quantum ergodic eigenfunctions one can get improvements of the results of Burq-Gérard-Tzvetkov, Hu, and Chen-Sogge. The improvements are logarithmic on negatively curved manifolds (without boundary) and by o(1) for manifolds (with or without boundary) with ergodic geodesic flows. In the case of ergodic billiards with piecewise smooth boundary, we get o(1) improvements on L^∞ estimates of Cauchy data away from a shrinking neighborhood of the corners, and as a result using the methods of Ghosh et al., Jung and Zelditch, Jung and Zelditch, we get that the number of nodal domains of 2-dimensional ergodic billiards tends to infinity as λ \\to ∞. These results work only for a full density subsequence of any given orthonormal basis of eigenfunctions. We also present an extension of the L p estimates of Burq-Gérard-Tzvetkov, Hu, Chen-Sogge for the restrictions of Dirichlet and Neumann eigenfunctions to compact submanifolds of the interior of manifolds with piecewise smooth boundary. This part does not assume ergodicity on the manifolds.

  19. International Conference on Ergodic Theory and Related Topics

    CERN Document Server

    Richter, Karin; Warstat, Volker

    1992-01-01

    The purpose of the conference was to represent recent developments in measure theoretic, differentiable and topological dynamical systems as well as connections to probability theory, stochastic processes, operator theory and statistical physics. Only original research papers that do not appear elsewhere are included in the proceedings. Their topics include: C(2)-diffeomorphisms of compact Riemann manifolds, geodesic flows, chaotic behaviour in billards, nonlinear ergodic theory, central limit theorems for subadditive processes, Hausdorff measures for parabolic rational maps, Markov operators, periods of cycles, Julia sets, ergodic theorems. From the Contents: L.A. Bunimovich: On absolutely focusing mirrors.- M. Denker, M. Urbanski: The dichotomy of Hausdorff measures and equilibrium states for parabolic rational maps.- F. Ledrappier: Ergodic properties of the stable foliations.- U. Wacker: Invariance principles and central limit theorems for nonadditive stationary processes.- J. Schmeling, R. Siegmund-Schult...

  20. On reducibility and ergodicity of population projection matrix models

    DEFF Research Database (Denmark)

    Stott, Iain; Townley, Stuart; Carslake, David

    2010-01-01

    from all stages to all other stages) and therefore ergodic (whatever initial stage structure is used in the population projection, it will always exhibit the same stable asymptotic growth rate). 2. Evaluation of 652 PPM models for 171 species from the literature suggests that 24·7% of PPM models...... structure used in the population projection). In our sample of published PPMs, 15·6% are non-ergodic. 3. This presents a problem: reducible–ergodic models often defy biological rationale in their description of the life cycle but may or may not prove problematic for analysis as they often behave similarly...... of reducibility in published PPMs, with significant implications for the predictive power of such models in many cases. We suggest that as a general rule, reducibility of PPM models should be avoided. However, we provide a guide to the pertinent analysis of reducible matrix models, largely based upon whether...

  1. The spectral method and ergodic theorems for general Markov chains

    International Nuclear Information System (INIS)

    Nagaev, S V

    2015-01-01

    We study the ergodic properties of Markov chains with an arbitrary state space and prove a geometric ergodic theorem. The method of the proof is new: it may be described as an operator method. Our main result is an ergodic theorem for Harris-Markov chains in the case when the return time to some fixed set has finite expectation. Our conditions for the transition function are more general than those used by Athreya-Ney and Nummelin. Unlike them, we impose restrictions not on the original transition function but on the transition function of an embedded Markov chain constructed from the return times to the fixed set mentioned above. The proof uses the spectral theory of linear operators on a Banach space

  2. An Estimation of the Logarithmic Timescale in Ergodic Dynamics

    Science.gov (United States)

    Gomez, Ignacio S.

    An estimation of the logarithmic timescale in quantum systems having an ergodic dynamics in the semiclassical limit, is presented. The estimation is based on an extension of the Krieger’s finite generator theorem for discretized σ-algebras and using the time rescaling property of the Kolmogorov-Sinai entropy. The results are in agreement with those obtained in the literature but with a simpler mathematics and within the context of the ergodic theory. Moreover, some consequences of the Poincaré’s recurrence theorem are also explored.

  3. Ergodic optimization in the expanding case concepts, tools and applications

    CERN Document Server

    Garibaldi, Eduardo

    2017-01-01

    This book focuses on the interpretation of ergodic optimal problems as questions of variational dynamics, employing a comparable approach to that of the Aubry-Mather theory for Lagrangian systems. Ergodic optimization is primarily concerned with the study of optimizing probability measures. This work presents and discusses the fundamental concepts of the theory, including the use and relevance of Sub-actions as analogues to subsolutions of the Hamilton-Jacobi equation. Further, it provides evidence for the impressively broad applicability of the tools inspired by the weak KAM theory.

  4. Efficient estimation for ergodic diffusions sampled at high frequency

    DEFF Research Database (Denmark)

    Sørensen, Michael

    A general theory of efficient estimation for ergodic diffusions sampled at high fre- quency is presented. High frequency sampling is now possible in many applications, in particular in finance. The theory is formulated in term of approximate martingale estimating functions and covers a large class...

  5. Conservative interacting particles system with anomalous rate of ergodicity

    OpenAIRE

    Brzeźniak, Zdzislaw; Flandoli, Franco; Neklyudov, Misha; Zegarliński, Boguslaw

    2010-01-01

    We analyze certain conservative interacting particle system and establish ergodicity of the system for a family of invariant measures. Furthermore, we show that convergence rate to equilibrium is exponential. This result is of interest because it presents counterexample to the standard assumption of physicists that conservative system implies polynomial rate of convergence.

  6. Ergodic Retractions for Families of Asymptotically Nonexpansive Mappings

    Directory of Open Access Journals (Sweden)

    Saeidi Shahram

    2010-01-01

    Full Text Available We prove some theorems for the existence of ergodic retractions onto the set of common fixed points of a family of asymptotically nonexpansive mappings. Our results extend corresponding results of Benavides and Ramírez (2001, and Li and Sims (2002.

  7. A stochastic Ergodic Theorem in Von-Neumann algebras | Tijani ...

    African Journals Online (AJOL)

    In this paper we introduce the notion of stochastic convergence of τ- measurable operators and prove a noncommutative extension of pointwise ergodic theorem of G. D. Birkhoff by means of it by using the techniques developed by Petz in [12] Journal of the Nigerian Association of Mathematical Physics Vol. 9 2005: pp.

  8. Plasma surface interactions in controlled fusion devices

    International Nuclear Information System (INIS)

    Ghendrih, Ph.; Becoulet, M.; Costanzo, L.

    2000-07-01

    This report brings together all the contributions of EURATOM/CEA association to the 14. international conference on plasma surface interactions in controlled fusion devices. 24 papers are presented and they deal mainly with the ergodic divertor and the first wall of Tore-supra tokamak

  9. Plasma surface interactions in controlled fusion devices

    Energy Technology Data Exchange (ETDEWEB)

    Ghendrih, Ph.; Becoulet, M.; Costanzo, L. [and others

    2000-07-01

    This report brings together all the contributions of EURATOM/CEA association to the 14. international conference on plasma surface interactions in controlled fusion devices. 24 papers are presented and they deal mainly with the ergodic divertor and the first wall of Tore-supra tokamak.

  10. Novel technique and simple approach for supra-alar region and supra-alar crease correction by supra-alar cinching.

    Science.gov (United States)

    Selvaraj, Loganathan

    2016-01-01

    This technical report describes a simple and innovative surgical technique for supra-alar sidewall region constriction and supra-alar crease attenuation by cinching technique through intraoral approach.

  11. Novel technique and simple approach for supra-alar region and supra-alar crease correction by supra-alar cinching

    OpenAIRE

    Selvaraj, Loganathan

    2016-01-01

    This technical report describes a simple and innovative surgical technique for supra-alar sidewall region constriction and supra-alar crease attenuation by cinching technique through intraoral approach.

  12. Ergodic model for the expansion of spherical nanoplasmas.

    Science.gov (United States)

    Peano, F; Coppa, G; Peinetti, F; Mulas, R; Silva, L O

    2007-06-01

    Recently, the collisionless expansion of spherical nanoplasmas has been analyzed with a new ergodic model, clarifying the transition from hydrodynamiclike to Coulomb-explosion regimes, and providing accurate laws for the relevant features of the phenomenon. A complete derivation of the model is presented here. The important issue of the self-consistent initial conditions is addressed by analyzing the initial charging transient due to the electron expansion, in the approximation of immobile ions. A comparison among different kinetic models for the expansion is presented, showing that the ergodic model provides a simplified description, which retains the essential information on the electron distribution, in particular, the energy spectrum. Results are presented for a wide range of initial conditions (determined from a single dimensionless parameter), in excellent agreement with calculations from the exact Vlasov-Poisson theory, thus providing a complete and detailed characterization of all the stages of the expansion.

  13. The Non-Ergodic Nature of Internal Conversion

    DEFF Research Database (Denmark)

    Kuhlman, Thomas Scheby

    The absorption of light by molecules can induce ultrafast dynamics of coupled electronic and nuclear vibrational motion. The ultrafast nature in many cases rests on the importance of several potential energy surfaces in guiding the nuclear dynamics – a concept of central importance in many aspects...... of chemical reaction dynamics. In this thesis, we focus on the non-ergodic nature of internal conversion, i.e. the concept that the nuclear dynamics only sample a reduced phase space potentially resulting in localization of the dynamics in real space. In essence, this is a consequence of vibrational energy...... cyclopentadienes and dithiane. In the case of the cycloketones, the rate of internal conversion varies by more than an order of magnitude between the molecules. This non-ergodic process was found to primarily involve ring-puckering motion, and the different timescales observed could be rationalized on the basis...

  14. Modelling of impurity transport in ergodic layer of LHD

    International Nuclear Information System (INIS)

    Feng, Y.; Masuzaki, S.; Morisaki, T.; Ohyabu, N.; Yamada, H.; Komori, A.; Motojima, O.; Kobayashi, M.

    2008-01-01

    The impurity transport properties in the ergodic layer of LHD are analyzed by the 3D edge transport code as well as 1D simple model, which is used to illustrate the essential transport terms in the analysis. It is found that as the plasma density increases the edge surface layers, very edge region of the ergodic layer, enters friction dominant regime, resulting in impurity retention. It is considered that the cause for the retention is both temperature drop and the flow acceleration in the edge surface layers. The edge surface layers can provide effective retention of impurities coming from divertor as well as the first wall, because of the geometrical advantage of the edge region of LHD. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Generic singular continuous spectrum for ergodic Schr\\"odinger operators

    OpenAIRE

    Avila, Artur; Damanik, David

    2004-01-01

    We consider Schr\\"odinger operators with ergodic potential $V_\\omega(n)=f(T^n(\\omega))$, $n \\in \\Z$, $\\omega \\in \\Omega$, where $T:\\Omega \\to \\Omega$ is a non-periodic homeomorphism. We show that for generic $f \\in C(\\Omega)$, the spectrum has no absolutely continuous component. The proof is based on approximation by discontinuous potentials which can be treated via Kotani Theory.

  16. Ergodicity-breaking bifurcations and tunneling in hyperbolic transport models

    Science.gov (United States)

    Giona, M.; Brasiello, A.; Crescitelli, S.

    2015-11-01

    One of the main differences between parabolic transport, associated with Langevin equations driven by Wiener processes, and hyperbolic models related to generalized Kac equations driven by Poisson processes, is the occurrence in the latter of multiple stable invariant densities (Frobenius multiplicity) in certain regions of the parameter space. This phenomenon is associated with the occurrence in linear hyperbolic balance equations of a typical bifurcation, referred to as the ergodicity-breaking bifurcation, the properties of which are thoroughly analyzed.

  17. Diophantine and minimal but not uniquely ergodic (almost)

    International Nuclear Information System (INIS)

    Kwapisz, Jaroslaw; Mathison, Mark

    2012-01-01

    We demonstrate that minimal non-uniquely ergodic behaviour can be generated by slowing down a simple harmonic oscillator with diophantine frequency, in contrast with the known examples where the frequency is well approximable by the rationals. The slowing is effected by a singular time change that brings one phase point to rest. The time one-map of the flow has uncountably many invariant measures yet every orbit is dense, with the minor exception of the rest point

  18. Discrete ergodic Jacobi matrices: Spectral properties and Quantum dynamical bounds

    OpenAIRE

    Han, Rui

    2017-01-01

    In this thesis we study discrete quasiperiodic Jacobi operators as well as ergodic operators driven by more general zero topological entropy dynamics. Such operators are deeply connected to physics (quantum Hall effect and graphene) and have enjoyed great attention from mathematics (e.g. several of Simon’s problems). The thesis has two main themes. First, to study spectral properties of quasiperiodic Jacobi matrices, in particular when off-diagonal sampling function has non-zero winding numbe...

  19. A mature industrial solution for ITER divertor plasma facing components: hypervapotron cooling concept adapted to Tore Supra flat tile technology

    Energy Technology Data Exchange (ETDEWEB)

    Escourbiac, F.; Missirlian, M.; Schlosser, J. [Association EURATOM-CEA Cadarache, Departement de Recherches sur la Fusion Controlee, 13 - Saint Paul lez Durance (France); Bobin-Vastra, I. [AREVA Centre Technique de Framatome, 71 - Le Creusot (France); Kuznetsov, V. [Efremov Institute, Doroga na Metallostroy, St. Petersburg (Russian Federation); Schedler, B. [Plansee AG, Reutte (Austria)

    2004-07-01

    The use of flat tile technology to handle heat fluxes in the range of 20 MW/m{sup 2} with components relevant for fusion experiment applications is technically possible with the hypervapotron cooling concept. This paper deals with recent high heat flux performances operated with success on 2 identical mock-ups, based on this concept, that were tested in 2 different electron gun facilities. Each mock-up consisted of a CuCrZr heat sink armored with 25 flat tiles of the 3D carbon fibre composite material SEPcarb NS31 assembled with pure copper by active metal casting (AMC). The AMC tiles were electron beam welded on the CuCrZr bar, fins and slots on the neutral beam JET design were machined into the bar, then the bar was closed with a thick CuCrZr rear plug including hydraulic connections then the bar was electron beam welded onto the sidewalls. The testing results show that full ITER design specifications were achieved with margins, the critical heat flux limit was even higher than 30 MW/m{sup 2}. These results highlight the high potential of this technology for ITER divertor application.

  20. Heat flux distribution and gyro-radius smoothing effect on misaligned CFC tile in the Tore Supra tokamak

    Czech Academy of Sciences Publication Activity Database

    Corre, Y.; Dejarnac, Renaud; Gardarein, J.-L.; Gaspar, J.; Escourbiac, F.; Gauthier, E.; Gunn, J. P.; Komm, Michael; Lipa, M.; Loarer, T.; Missirlian, M.; Rigollet, F.

    2015-01-01

    Roč. 463, August (2015), s. 832-836 ISSN 0022-3115. [PLASMA-SURFACE INTERACTIONS 21: International Conference on Plasma-Surface Interactions in Controlled Fusion Devices. Kanazawa, 26.05.2014-30.05.2014] Institutional support: RVO:61389021 Keywords : Heat loads * IR thermography * misalignment * limiter Subject RIV: JF - Nuclear Energetics OBOR OECD: Nuclear related engineering Impact factor: 2.199, year: 2015 http://www.sciencedirect.com/science/article/pii/S002231151400720X

  1. A mature industrial solution for ITER divertor plasma facing components: hypervapotron cooling concept adapted to Tore Supra flat tile technology

    International Nuclear Information System (INIS)

    Escourbiac, F.; Missirlian, M.; Schlosser, J.; Bobin-Vastra, I.; Kuznetsov, V.; Schedler, B.

    2004-01-01

    The use of flat tile technology to handle heat fluxes in the range of 20 MW/m 2 with components relevant for fusion experiment applications is technically possible with the hypervapotron cooling concept. This paper deals with recent high heat flux performances operated with success on 2 identical mock-ups, based on this concept, that were tested in 2 different electron gun facilities. Each mock-up consisted of a CuCrZr heat sink armored with 25 flat tiles of the 3D carbon fibre composite material SEPcarb NS31 assembled with pure copper by active metal casting (AMC). The AMC tiles were electron beam welded on the CuCrZr bar, fins and slots on the neutral beam JET design were machined into the bar, then the bar was closed with a thick CuCrZr rear plug including hydraulic connections then the bar was electron beam welded onto the sidewalls. The testing results show that full ITER design specifications were achieved with margins, the critical heat flux limit was even higher than 30 MW/m 2 . These results highlight the high potential of this technology for ITER divertor application

  2. Measurements of heat transfer coefficients at low contact pressures for actively cooled bolted armour concepts in Tore Supra

    International Nuclear Information System (INIS)

    Lipa, M.; Chappuis, Ph.; Dufayet, A.

    2000-01-01

    For the future upgrade of inner vessel components (CIEL project) a guard limiter for plasma ramp-up and disruption protection will be installed on the high field side of the vacuum vessel. Among transient heat loads, this structure has to sustain a moderate heat flux in the range of ≤0.5 MW/m 2 during quasi steady state operation (1000 s). A bolted carbon-carbon (C-C) tile is preferred compared with a brazed tile solution due to the expected moderate heat fluxes, costs and the possibility of rapid replacement of individual tiles. Large flat tile assemblies require a sufficient soft and conductive compliant layer enclosed between tile and heat sink in order to avoid thermal contact loss of the assembly during heat loads and therefore minimising the tile surface temperature. The global heat transfer coefficient (H gl ) under vacuum at low contact pressures (0.5-1.5 MPa) between C-C and CuCrZr heat sink substrata has been measured in the experimental device, installation of contact heat transfer measurements (ITTAC), using different compliant materials. It appears that the best compliant layer is a graphite sheet (PAPYEX), compared with copper-felt/foam material. As an example, a H gl number of ∼10 4 W/m 2 K at an average contact pressure of 0.5 MPa has been measured near room temperature between C-C (SEP N11) and CuCrZr substrata using a 0.5-mm thick PAPYEX layer. Thermohydraulic calculations (2D) of the guard limiter design show an expected tile surface temperature of about 550 deg. C in steady state regime for an incident heat flux of 0.5 MW/m 2

  3. Resistive flux saving and current profile control during lower hybrid waves assisted current rise in TORE SUPRA

    International Nuclear Information System (INIS)

    van Houtte, D.; Hoang, G.T.; Joffrin, E.; Lecoustey, P.; Moreau, D.; Parlange, F.; Tonon, G.; Vallet, J.C.

    1992-01-01

    Resistive flux saving at densities n e = (1 - 2) x 10 19 m -3 has been studied. High flux saving efficiency (0.7 x 10 13 Wb/J/m -1 ) can be achieved for a low rf power (P LH = 0.5 MW) due to the beneficial effect of the electric field on the suprathermal electrons. However for power higher than 1 MW, the efficiency is 0.25 x 10 13 Wb/J/m -1 . This flux saving efficiency is comparable to the one obtained during the flat top phase. The application of the LH power during a low density current ramp-up tends to peak the electron temperature and current density profiles. The rf power level, the parallel wavenumber and the current ramp rate allow to control the trajectories of the plasma discharges during the current rise inside the MHD stable domain

  4. Validation of the ITER-relevant passive-active-multijunction LHCD launcher on long pulses in Tore Supra

    Czech Academy of Sciences Publication Activity Database

    Ekedahl, A.; Delpech, L.; Goniche, M.; Guilhem, D.; Hillairet, J.; Preynas, M.; Sharma, P.K.; Achard, J.; Bae, Y.S.; Bai, X.; Balorin, C.; Baranov, Y.; Basiuk, V.; Bécoulet, A.; Belo, J.; Berger-By, G.; Brémond, S.; Castaldo, C.; Ceccuzzi, S.; Cesario, R.; Corbel, E.; Courtois, X.; Decker, J.; Delmas, E.; Ding, X.; Douai, D.; Goletto, C.; Gunn, J. P.; Hertout, P.; Hoang, G.T.; Imbeaux, F.; Kirov, K.K.; Litaudon, X.; Magne, R.; Mailloux, J.; Mazon, D.; Mirizzi, F.; Mollard, P.; Moreau, P.; Oosako, T.; Petržílka, Václav; Peysson, Y.; Poli, S.; Prou, M.; Saint-Laurent, F.; Samaille, F.; Saoutic, B.

    2010-01-01

    Roč. 50, č. 11 (2010), s. 112002-112002 ISSN 0029-5515 Institutional research plan: CEZ:AV0Z20430508 Keywords : LH wave * plasma Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.303, year: 2010 http://iopscience.iop.org/0029-5515/50/11/112002/pdf/0029-5515_50_11_112002.pdf

  5. Soft x-ray tomography for real-time applications: present status at Tore Supra and possible future developments

    Czech Academy of Sciences Publication Activity Database

    Mazon, D.; Vezinet, D.; Pacella, D.; Moreau, D.; Gabelieri, L.; Romano, A.; Malard, P.; Mlynář, Jan; Masset, R.; Lotte, P.

    2012-01-01

    Roč. 83, č. 6 (2012), 063505-063505 ISSN 0034-6748 Institutional research plan: CEZ:AV0Z20430508 Keywords : Tokamak * tomography X-ray * diagnostics Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.602, year: 2012 http://rsi.aip.org/resource/1/rsinak/v83/i6/p063505_s1

  6. Results of water corrosion in static cell tests representing multi-metal assemblies in the hydraulic circuits of Tore supra

    Energy Technology Data Exchange (ETDEWEB)

    Lipa, M. [CEA/DSM/DRFC Centre de Cadarache, 13 - Saint-Paul lez Durance (France); Blanchet, J.; Cellier, F. [Framatome, 71 - Saint Marcel (France). Centre Technique

    2007-07-01

    Following experiences obtained with steam generator tubes of nuclear power plants, a cooling water quality of AVT (all volatile treatment) has been defined based on demineralised water with adjustment of the pH value to about 9.0/7.0 (25 C/200 C) by addiction of ammoniac, and hydrazine in order to absorb oxygen dissolved in water. At that time, a simplified water corrosion test program has been performed using static (no circulation) test cell samples made of above mentioned TS metal combinations. All test cell samples, prepared and filled with AVT water, were performed at 280 C and 65 bars in an autoclave during 3000 hours. The test cell water temperature has been chosen to be sufficient above the TS component working temperature, in order to accelerate an eventual corrosion process. Generally all above mentioned metal combinations survived the test campaign without stress corrosion cracking, with the exception of the memory metal junction (creep in Cu) and the bellows made of St-St 316L and Inconel 625 while 316 Ti bellows survived. In contrary to the vacuum brazed Cu-LSTP to St-St samples, some of flame brazed Cu to St-St samples failed either in the braze joint or in the copper structure itself. For comparison, a spot weld of an inflated 316L panel sample, filled voluntary with a caustic solution of pH 11.5 (25 C), failed after 90 h of testing (intergranular cracking at the spot weld), while an identical sample containing AVT water of pH 9.0 (25 C) survived without damage. The results of these tests, performed during 1986 and 1997, have never been published and therefore are presented more in detail in this paper since corrosion in hydraulic circuits is also an issue of ITER. Up to day, the TS cooling water plant operates with an above mentioned water treatment and no water leaks have been detected on in-vessel components originating from water corrosion at high temperature and high pressure. (orig.)

  7. Results of water corrosion in static cell tests representing multi-metal assemblies in the hydraulic circuits of Tore supra

    International Nuclear Information System (INIS)

    Lipa, M.; Blanchet, J.; Cellier, F.

    2007-01-01

    Following experiences obtained with steam generator tubes of nuclear power plants, a cooling water quality of AVT (all volatile treatment) has been defined based on demineralised water with adjustment of the pH value to about 9.0/7.0 (25 C/200 C) by addiction of ammoniac, and hydrazine in order to absorb oxygen dissolved in water. At that time, a simplified water corrosion test program has been performed using static (no circulation) test cell samples made of above mentioned TS metal combinations. All test cell samples, prepared and filled with AVT water, were performed at 280 C and 65 bars in an autoclave during 3000 hours. The test cell water temperature has been chosen to be sufficient above the TS component working temperature, in order to accelerate an eventual corrosion process. Generally all above mentioned metal combinations survived the test campaign without stress corrosion cracking, with the exception of the memory metal junction (creep in Cu) and the bellows made of St-St 316L and Inconel 625 while 316 Ti bellows survived. In contrary to the vacuum brazed Cu-LSTP to St-St samples, some of flame brazed Cu to St-St samples failed either in the braze joint or in the copper structure itself. For comparison, a spot weld of an inflated 316L panel sample, filled voluntary with a caustic solution of pH 11.5 (25 C), failed after 90 h of testing (intergranular cracking at the spot weld), while an identical sample containing AVT water of pH 9.0 (25 C) survived without damage. The results of these tests, performed during 1986 and 1997, have never been published and therefore are presented more in detail in this paper since corrosion in hydraulic circuits is also an issue of ITER. Up to day, the TS cooling water plant operates with an above mentioned water treatment and no water leaks have been detected on in-vessel components originating from water corrosion at high temperature and high pressure. (orig.)

  8. Ergodic time-reversible chaos for Gibbs' canonical oscillator

    International Nuclear Information System (INIS)

    Hoover, William Graham; Sprott, Julien Clinton; Patra, Puneet Kumar

    2015-01-01

    Nosé's pioneering 1984 work inspired a variety of time-reversible deterministic thermostats. Though several groups have developed successful doubly-thermostated models, single-thermostat models have failed to generate Gibbs' canonical distribution for the one-dimensional harmonic oscillator. A 2001 doubly-thermostated model, claimed to be ergodic, has a singly-thermostated version. Though neither of these models is ergodic this work has suggested a successful route toward singly-thermostated ergodicity. We illustrate both ergodicity and its lack for these models using phase-space cross sections and Lyapunov instability as diagnostic tools. - Highlights: • We develop cross-section and Lyapunov methods for diagnosing ergodicity. • We apply these methods to several thermostatted-oscillator problems. • We demonstrate the nonergodicity of previous work. • We find a novel family of ergodic thermostatted-oscillator problems.

  9. Supra-National Organisations and Conflict Resolution during the ...

    African Journals Online (AJOL)

    Supra-National Organisations and Conflict Resolution during the Nigeria Civil War: ... or part of the non-state actors that impinge on the international environment. ... the importance or roles of Supra-national organisations in conflict resolution ...

  10. Controlled thermonuclear reactions and Tora Supra program

    International Nuclear Information System (INIS)

    1988-01-01

    The research programs for the nuclear energy production by means of thermonuclear fusion are shown. TORA SUPRA, Joint European Torus, Next European Torus and those developed at the Atomic Energy Center are described. The controlled fusion necessary conditions, the energy and confinement balance, and the research of a better tokamak configuration are discussed. A description of TORA SUPRA, the ways of achieving the project and the expected delays are shown. The Controlled Fusion Research Department functions, concerning these programs, are described. The importance of international cooperation and the perspectives about the use of controlled fusion are underlined [fr

  11. Improvement of Fuzzy Image Contrast Enhancement Using Simulated Ergodic Fuzzy Markov Chains

    Directory of Open Access Journals (Sweden)

    Behrouz Fathi-Vajargah

    2014-01-01

    Full Text Available This paper presents a novel fuzzy enhancement technique using simulated ergodic fuzzy Markov chains for low contrast brain magnetic resonance imaging (MRI. The fuzzy image contrast enhancement is proposed by weighted fuzzy expected value. The membership values are then modified to enhance the image using ergodic fuzzy Markov chains. The qualitative performance of the proposed method is compared to another method in which ergodic fuzzy Markov chains are not considered. The proposed method produces better quality image.

  12. Equilibrium states and the ergodic theory of Anosov diffeomorphisms

    CERN Document Server

    2008-01-01

    For this printing of R. Bowen's book, J.-R. Chazottes has retyped it in TeX for easier reading, thereby correcting typos and bibliographic details. From the Preface by D. Ruelle: "Rufus Bowen has left us a masterpiece of mathematical exposition... Here a number of results which were new at the time are presented in such a clear and lucid style that Bowen's monograph immediately became a classic. More than thirty years later, many new results have been proved in this area, but the volume is as useful as ever because it remains the best introduction to the basics of the ergodic theory of hyperbolic systems."

  13. Asymptotic Ergodic Capacity Analysis of Composite Lognormal Shadowed Channels

    KAUST Repository

    Ansari, Imran Shafique

    2015-05-01

    Capacity analysis of composite lognormal (LN) shadowed links, such as Rician-LN, Gamma-LN, and Weibull-LN, is addressed in this work. More specifically, an exact closed-form expression for the moments of the end-to-end signal-to-noise ratio (SNR) of a single composite link transmission system is presented in terms of well- known elementary functions. Capitalizing on these new moments expressions, we present asymptotically tight lower bounds for the ergodic capacity at high SNR. All the presented results are verified via computer-based Monte-Carlo simulations. © 2015 IEEE.

  14. Topology, ergodic theory, real algebraic geometry Rokhlin's memorial

    CERN Document Server

    Turaev, V

    2001-01-01

    This book is dedicated to the memory of the outstanding Russian mathematician, V. A. Rokhlin (1919-1984). It is a collection of research papers written by his former students and followers, who are now experts in their fields. The topics in this volume include topology (the Morse-Novikov theory, spin bordisms in dimension 6, and skein modules of links), real algebraic geometry (real algebraic curves, plane algebraic surfaces, algebraic links, and complex orientations), dynamics (ergodicity, amenability, and random bundle transformations), geometry of Riemannian manifolds, theory of Teichmüller

  15. Asymptotic Ergodic Capacity Analysis of Composite Lognormal Shadowed Channels

    KAUST Repository

    Ansari, Imran Shafique; Alouini, Mohamed-Slim

    2015-01-01

    Capacity analysis of composite lognormal (LN) shadowed links, such as Rician-LN, Gamma-LN, and Weibull-LN, is addressed in this work. More specifically, an exact closed-form expression for the moments of the end-to-end signal-to-noise ratio (SNR) of a single composite link transmission system is presented in terms of well- known elementary functions. Capitalizing on these new moments expressions, we present asymptotically tight lower bounds for the ergodic capacity at high SNR. All the presented results are verified via computer-based Monte-Carlo simulations. © 2015 IEEE.

  16. Ergodic theory, interpretations of probability and the foundations of statistical mechanics

    NARCIS (Netherlands)

    van Lith, J.H.

    2001-01-01

    The traditional use of ergodic theory in the foundations of equilibrium statistical mechanics is that it provides a link between thermodynamic observables and microcanonical probabilities. First of all, the ergodic theorem demonstrates the equality of microcanonical phase averages and infinite time

  17. Ergodicity, hidden bias and the growth rate gain

    Science.gov (United States)

    Rochman, Nash D.; Popescu, Dan M.; Sun, Sean X.

    2018-05-01

    Many single-cell observables are highly heterogeneous. A part of this heterogeneity stems from age-related phenomena: the fact that there is a nonuniform distribution of cells with different ages. This has led to a renewed interest in analytic methodologies including use of the ‘von Foerster equation’ for predicting population growth and cell age distributions. Here we discuss how some of the most popular implementations of this machinery assume a strong condition on the ergodicity of the cell cycle duration ensemble. We show that one common definition for the term ergodicity, ‘a single individual observed over many generations recapitulates the behavior of the entire ensemble’ is implied by the other, ‘the probability of observing any state is conserved across time and over all individuals’ in an ensemble with a fixed number of individuals but that this is not true when the ensemble is growing. We further explore the impact of generational correlations between cell cycle durations on the population growth rate. Finally, we explore the ‘growth rate gain’—the phenomenon that variations in the cell cycle duration leads to an improved population-level growth rate—in this context. We highlight that, fundamentally, this effect is due to asymmetric division.

  18. Fluctuation, stationarity, and ergodic properties of random-matrix ensembles

    International Nuclear Information System (INIS)

    Pandey, A.

    1979-01-01

    The properties of random-matrix ensembles and the application of such ensembles to energy-level fluctuations and strength fluctuations are discussed. The two-point correlation function for complex spectra described by the three standard Gaussian ensembles is calculated, and its essential simplicity, displayed by an elementary procedure that derives from the dominance of binary correlations. The resultant function is exact for the unitary case and a very good approximation to the orthogonal and symplectic cases. The same procedure yields the spectrum for a Gaussian orthogonal ensemble (GOE) deformed by a pairing interaction. Several extensions are given and relationships to other problems of current interest are discussed. The standard fluctuation measures are rederived for the GOE, and their extensions to the unitary and symplectic cases are given. The measures are shown to derive, for the most part, from the two-point function, and new relationships between them are established, answering some long-standing questions. Some comparisons with experimental values are also made. All the cluster functions, and therefore the fluctuation measures, are shown to be stationary and strongly ergodic, thus justifying the use of random matrices for individual spectra. Strength fluctuations in the orthogonal ensemble are also considered. The Porter-Thomas distribution in its various forms is rederived and its ergodicity is established

  19. Characterisation of Supra- and Infratentorial ICP Profiles.

    Science.gov (United States)

    Moyse, Emmanuel; Ros, Maxime; Marhar, Fouad; Swider, Pascal; Schmidt, Eric Albert

    2016-01-01

    In pathophysiology and clinical practice, the intracranial pressure (ICP) profiles in the supratentorial and infratentorial compartments are unclear. We know that the pressure within the skull is unevenly distributed, with demonstrated ICP gradients. We recorded and characterised the supra- and infratentorial ICP patterns to understand what drives the transtentorial ICP gradient.A 70-year-old man was operated on for acute cerebellar infarction. One supratentorial probe and one cerebellar probe were implanted. Both signals were recorded concurrently and analysed off-line. We calculated mean ICP, ICP pulse amplitude, respiratory waves, slow waves and the RAP index of supra- and infratentorial ICP signals. Then, we measured transtentorial difference and performed correlation analysis for every index.Supratentorial ICP mean was 8.5 mmHg lower than infratentorial ICP, but the difference lessens for higher values. Both signals across the tentorium showed close correlation. Supra- and infratentorial pulse amplitude, respiratory waves and slow waves also showed a high degree of correlation. The compensatory reserve (RAP) showed good correlation. In this case report, we demonstrate that the mean value of ICP is higher in the posterior fossa, with a strong correlation across the tentorium. All other ICP-derived parameters display a symmetrical profile.

  20. Physics aspects of the dynamic ergodic divertor (DED)

    International Nuclear Information System (INIS)

    Finken, Karl H.; Kobayashi, Masahiro; Abdullaev, Sadrilla S.; Jakubowski, Marcin

    2003-01-01

    The Dynamic Ergonic Divertor (DED) is presently being installed in the TEXTOR tokamak. It consists of 16 helical coils wound helically around the torus at the high field side (HFS). The perturbation currents in these coils generate predominantly islands of m=10...14 and n=4 leading both to rather closed ergodic and to open laminar structures. In the 'laminar mode', the DED forms a helical divertor. 3D modelling (2D finite element/1 D finite volume) of the plasma transport in the laminar zone has started. By the 'dynamic' operation of the DED, the heat is deposited to a wide area and forces are transferred from the currents in the DED-coils to the plasma edge. (author)

  1. The Non-Ergodic Nature of Internal Conversion

    DEFF Research Database (Denmark)

    Sølling, Theis I.; Kuhlman, Thomas Scheby; Stephansen, Anne B.

    2014-01-01

    The absorption of light by molecules can induce ultrafast dynamics and coupling of electronic and nuclear vibrational motion. The ultrafast nature in many cases rests on the importance of several potential energy surfaces in guiding the nuclear motion—a concept of central importance in many aspects...... of chemical reaction dynamics. This Minireview focuses on the non-ergodic nature of internal conversion, that is, on the concept that the nuclear dynamics only sample a reduced phase space, potentially resulting in localization of the dynamics in real space. A series of results that highlight...... it takes to reach it. 2) Localization of energy into a single reactive mode, which is dictated by the internal conversion process. 3) Initiation of the internal conversion by activation of a single complex motion, which then specifically couples to a reactive mode. 4) Nonstatistical internal conversion...

  2. On the rate of convergence in von Neumann's ergodic theorem with continuous time

    International Nuclear Information System (INIS)

    Kachurovskii, A G; Reshetenko, Anna V

    2010-01-01

    The rate of convergence in von Neumann's mean ergodic theorem is studied for continuous time. The condition that the rate of convergence of the ergodic averages be of power-law type is shown to be equivalent to requiring that the spectral measure of the corresponding dynamical system have a power-type singularity at 0. This forces the estimates for the convergence rate in the above ergodic theorem to be necessarily spectral. All the results obtained have obvious exact analogues for wide-sense stationary processes. Bibliography: 7 titles.

  3. Asymptotic behaviour of time averages for non-ergodic Gaussian processes

    Science.gov (United States)

    Ślęzak, Jakub

    2017-08-01

    In this work, we study the behaviour of time-averages for stationary (non-ageing), but ergodicity-breaking Gaussian processes using their representation in Fourier space. We provide explicit formulae for various time-averaged quantities, such as mean square displacement, density, and analyse the behaviour of time-averaged characteristic function, which gives insight into rich memory structure of the studied processes. Moreover, we show applications of the ergodic criteria in Fourier space, determining the ergodicity of the generalised Langevin equation's solutions.

  4. What Then Happens When Interaction is Not Possible: The Virtuosic Interpretation of Ergodic Artefacts

    Directory of Open Access Journals (Sweden)

    Miguel Carvalhais

    2015-11-01

    Full Text Available Procedural systems allow unique modes of authorship and singular aesthetic experiences. As creators and users of these systems, we need to be aware that their aesthetic potential is not solely defined by interaction but that interpretation, and the capacity to understand and simulate the processes taking place within these artefacts is highly significant. This paper argues that although direct interaction is usually the most discernible component in the relationship between ergodic artefacts and their users, ergodicity does not necessarily imply interaction. Non-interactive procedural artefacts may allow the development of ergodic experiences through interpretation, and the probing of the system by its reader through simulations. We try to set the grounds for designing towards virtuosic interpretation, an activity that we may describe as the ergodic experience developed by means of mental simulation through the development of theories of systems.

  5. Rates of convergence and asymptotic normality of curve estimators for ergodic diffusion processes

    NARCIS (Netherlands)

    J.H. van Zanten (Harry)

    2000-01-01

    textabstractFor ergodic diffusion processes, we study kernel-type estimators for the invariant density, its derivatives and the drift function. We determine rates of convergence and find the joint asymptotic distribution of the estimators at different points.

  6. Ergodic theory and dynamical systems from a physical point of view

    International Nuclear Information System (INIS)

    Sabbagan, M.; Nasertayoob, P.

    2008-01-01

    Ergodic theory and a large part of dynamical systems are in essence some mathematical modeling, which belongs to statistical physics. This paper is an attempt to present some of the results and principles in ergodic theory and dynamical systems from certain view points of physics such as thermodynamics and classical mechanics. The significance of the varational principle in the statistical physics, the relation between classical approach and statistical approach, also comparison between reversibility from statistical of view are discussed. (author)

  7. Destruction of magnetic surfaces in the edge of a large aspect ratio Tokamak with ergodic limiter

    International Nuclear Information System (INIS)

    Viana, R.L.; Caldas, I.L.

    1990-01-01

    The model of Martin and Taylor for a large aspect-ratio Tokamak with an ergodic limiter is considered. In order to study the onset of chaotic behaviour for the magnetic field lines in the edge of the vessel, a Hamiltonian formulation is constructed for the system and the overlap of two peripheral magnetic islands is considered. So, it is possible to determine a threshold for the ergodic limiter current to cause destruction of rational magnetic surfaces in this region. (Author)

  8. In vivo Anomalous Diffusion and Weak Ergodicity Breaking of Lipid Granules

    DEFF Research Database (Denmark)

    Jeon, J.-H.; Tejedor, V.; Burov, S.

    2011-01-01

    Combining extensive single particle tracking microscopy data of endogenous lipid granules in living fission yeast cells with analytical results we show evidence for anomalous diffusion and weak ergodicity breaking. Namely we demonstrate that at short times the granules perform subdiffusion...... according to the laws of continuous time random walk theory. The associated violation of ergodicity leads to a characteristic turnover between two scaling regimes of the time averaged mean squared displacement. At longer times the granule motion is consistent with fractional Brownian motion....

  9. Let the Game Begin: Ergodic as an Approach for Video Game Translation

    OpenAIRE

    SF. Lukfianka Sanjaya Purnama; SF. Luthfie Arguby Purnomo; Dyah Nugrahani

    2016-01-01

    This paper attempts to propose ergodic as an approach for video game translation. The word approach here refers to an approach for translation products and to an approach for the translation process. The steps to formulate ergodic as an approach are first, Aarseth’sergodic literature is reviewed to elicit a basis for comprehension toward its relationship with video games and video game translation Secondly, taking the translation of Electronic Arts’Need for Speed: Own the City, Midway’s Morta...

  10. Ergodicity and Parameter Estimates for Infinite-Dimensional Fractional Ornstein-Uhlenbeck Process

    International Nuclear Information System (INIS)

    Maslowski, Bohdan; Pospisil, Jan

    2008-01-01

    Existence and ergodicity of a strictly stationary solution for linear stochastic evolution equations driven by cylindrical fractional Brownian motion are proved. Ergodic behavior of non-stationary infinite-dimensional fractional Ornstein-Uhlenbeck processes is also studied. Based on these results, strong consistency of suitably defined families of parameter estimators is shown. The general results are applied to linear parabolic and hyperbolic equations perturbed by a fractional noise

  11. Modelling of ion thermal transport in ergodic region of collisionless toroidal plasma

    International Nuclear Information System (INIS)

    Kanno, Ryutaro; Nunami, Masanori; Satake, Shinsuke; Ohyabu, Nobuyoshi; Takamaru, Hisanori; Okamoto, Masao

    2009-09-01

    In recent tokamak experiments it has been found that so-called diffusion theory based on the 'diffusion of magnetic field lines' overestimates the radial energy transport in the ergodic region of the collisionless plasma affected by resonant magnetic perturbations (RMPs), though the RMPs induce chaotic behavior of the magnetic field lines. The result implies that the modelling of the transport should be reconsidered for low collisionality cases. A computer simulation study of transport in the ergodic region is required for understanding fundamental properties of collisionless ergodized-plasmas, estimating the transport coefficients, and reconstructing the modelling of the transport. In this paper, we report the simulation study of thermal transport in the ergodic region under the assumption of neglecting effects of an electric field, impurities and neutrals. Because of the simulations neglecting interactions with different particle-species and saving the computational time, we treat ions (protons) in our numerical-study of the transport. We find that the thermal diffusivity in the ergodic region is extremely small compared to the one predicted by the theory of field-line diffusion and that the diffusivity depends on both the collision frequency and the strength of RMPs even for the collisionless ergodized-plasma. (author)

  12. Ergodicity of the Stochastic Nosé-Hoover Heat Bath

    Science.gov (United States)

    Wei Chung Lo,; Baowen Li,

    2010-07-01

    We numerically study the ergodicity of the stochastic Nosé-Hoover heat bath whose formalism is based on the Markovian approximation for the Nosé-Hoover equation [J. Phys. Soc. Jpn. 77 (2008) 103001]. The approximation leads to a Langevin-like equation driven by a fluctuating dissipative force and multiplicative Gaussian white noise. The steady state solution of the associated Fokker-Planck equation is the canonical distribution. We investigate the dynamics of this method for the case of (i) free particle, (ii) nonlinear oscillators and (iii) lattice chains. We derive the Fokker-Planck equation for the free particle and present approximate analytical solution for the stationary distribution in the context of the Markovian approximation. Numerical simulation results for nonlinear oscillators show that this method results in a Gaussian distribution for the particles velocity. We also employ the method as heat baths to study nonequilibrium heat flow in one-dimensional Fermi-Pasta-Ulam (FPU-β) and Frenkel-Kontorova (FK) lattices. The establishment of well-defined temperature profiles are observed only when the lattice size is large. Our results provide numerical justification for such Markovian approximation for classical single- and many-body systems.

  13. An Amylase-Responsive Bolaform Supra-Amphiphile.

    Science.gov (United States)

    Kang, Yuetong; Cai, Zhengguo; Tang, Xiaoyan; Liu, Kai; Wang, Guangtong; Zhang, Xi

    2016-02-01

    An amylase-responsive bolaform supra-amphiphile was constructed by the complexation between β-cyclodextrin and a bolaform covalent amphiphile on the basis of host-guest interaction. The bolaform covalent amphiphile could self-assemble in solution, forming sheet-like aggregates and displaying weak fluorescence because of aggregation-induced quenching. The addition of β-cyclodextrin led to the formation of the bolaform supra-amphiphile, prohibiting the aggregation of the bolaform covalent amphiphile and accompanying with the significant recovery of fluorescence. Upon the addition of α-amylase, with the degradation β-cyclodextrin, the fluorescence of the supra-amphiphile would quench gradually and significantly, and the quenching rate linearly correlated to the concentration of α-amylase. This study enriches the field of supra-amphiphiles on the basis of noncovalent interactions, and moreover, it may provide a facile way to estimate the activity of α-amylase.

  14. EURATOM-CEA association contributions to the 21st symposium on fusion technology

    International Nuclear Information System (INIS)

    Garin, P.; Grosman, A.; Beaumont, B.

    2000-11-01

    The 27 contributions of EURATOM-Cea association have been gathered with 6 additional papers and 1 invited paper in this document. Most papers concern Tore-Supra and deal with the ergodic divertor, particle injection, impedance concept for ICRF antennas, low hybrid current drive, RF systems, the 118 GHz ECRH experiment, the inner first wall, improved vacuum vessel protection, pellet injection, material activation, and the CIEL project. 3 of the additional papers concern the model coil of ITER

  15. EURATOM-CEA association contributions to the 21st symposium on fusion technology

    Energy Technology Data Exchange (ETDEWEB)

    Garin, P; Grosman, A; Beaumont, B [and others

    2000-11-01

    The 27 contributions of EURATOM-Cea association have been gathered with 6 additional papers and 1 invited paper in this document. Most papers concern Tore-Supra and deal with the ergodic divertor, particle injection, impedance concept for ICRF antennas, low hybrid current drive, RF systems, the 118 GHz ECRH experiment, the inner first wall, improved vacuum vessel protection, pellet injection, material activation, and the CIEL project. 3 of the additional papers concern the model coil of ITER.

  16. Ergodic theory and negative curvature CIRM Jean-Morlet Chair, Fall 2013

    CERN Document Server

    2017-01-01

    Focussing on the mathematics related to the recent proof of ergodicity of the (Weil–Petersson) geodesic flow on a nonpositively curved space whose points are negatively curved metrics on surfaces, this book provides a broad introduction to an important current area of research. It offers original textbook-level material suitable for introductory or advanced courses as well as deep insights into the state of the art of the field, making it useful as a reference and for self-study.  The first chapters introduce hyperbolic dynamics, ergodic theory and geodesic and horocycle flows, and include an English translation of Hadamard's original proof of the Stable-Manifold Theorem. An outline of the strategy, motivation and context behind the ergodicity proof is followed by a careful exposition of it (using the Hopf argument) and of the pertinent context of Teichmüller theory. Finally, some complementary lectures describe the deep connections between geodesic flows in negative curvature and Diophantine approximatio...

  17. On the Ergodic Capacity of Dual-Branch Correlated Log-Normal Fading Channels with Applications

    KAUST Repository

    Al-Quwaiee, Hessa

    2015-05-01

    Closed-form expressions of the ergodic capacity of independent or correlated diversity branches over Log-Normal fading channels are not available in the literature. Thus, it is become of an interest to investigate the behavior of such metric at high signal-to-noise (SNR). In this work, we propose simple closed-form asymptotic expressions of the ergodic capacity of dual-branch correlated Log- Normal corresponding to selection combining, and switch-and-stay combining. Furthermore, we capitalize on these new results to find new asymptotic ergodic capacity of correlated dual- branch free-space optical communication system under the impact of pointing error with both heterodyne and intensity modulation/direct detection. © 2015 IEEE.

  18. EURATOM-CEA association contributions to the 26. EPS conference on controlled fusion and plasma physics, Maastricht

    International Nuclear Information System (INIS)

    1999-10-01

    This report references the EURATOM-CEA association contributions presented at the 26. EPS conference on controlled fusion and plasma physics, in Maastricht (Netherlands) the 14-18 June 1999. Two invited papers and 24 contributed papers are proposed. They deal with: tokamak devices; particle recirculation in ergodic divertor; current profile control and MHD stability in Tore Supra discharges; edge-plasma control by the ergodic divertor; electron heat transport in stochastic magnetic layer; bolometry and radiated power; particle collection by ergodic divertor; study and simulation of plasma impurities; line shape modelling for plasma edge conditions; dynamical study of the radial structure of the fluctuations measured by reciprocating Langmuir probe in Tore Supra; up-down asymmetry of density fluctuations; Halo currents in a circular tokamak; real time measurement of the position, density, profile and current profile at Tore Supra; poloidal rotation measurement by reflectometry; interpretation of q-profile dependence of the LH power deposition profile during LHCD experiments; ICFR plasma production and optimization; improved core electron confinement; measurement of hard X-ray emission profile; modelling of shear effects on thermal and particles transport; ion turbulence; current drive generation based on autoresonance and intermittent trapping mechanisms. (A.L.B.)

  19. EURATOM-CEA association contributions to the 26. EPS conference on controlled fusion and plasma physics, Maastricht

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-10-15

    This report references the EURATOM-CEA association contributions presented at the 26. EPS conference on controlled fusion and plasma physics, in Maastricht (Netherlands) the 14-18 June 1999. Two invited papers and 24 contributed papers are proposed. They deal with: tokamak devices; particle recirculation in ergodic divertor; current profile control and MHD stability in Tore Supra discharges; edge-plasma control by the ergodic divertor; electron heat transport in stochastic magnetic layer; bolometry and radiated power; particle collection by ergodic divertor; study and simulation of pa impurities; line shape modelling for plasma edge conditions; dynamical study of the radial structure of the fluctuations measured by reciprocating Langmuir probe in Tore Supra; up-down asymmetry of density fluctuations; Halo currents in a circular tokamak; real time measurement of the position, density, profile and current profile at Tore Supra; poloidal rotation measurement by reflectometry; interpretation of q-profile dependence of the LH power deposition profile during LHCD experiments; ICFR plasma production and optimization; improved core electron confinement; measurement of hard X-ray emission profile; modelling of shear effects on thermal and particles transport; ion turbulence; current drive generation based on autoresonance and intermittent trapping mechanisms. (A.L.B.)

  20. Persistence and ergodicity of plant disease model with markov conversion and impulsive toxicant input

    Science.gov (United States)

    Zhao, Wencai; Li, Juan; Zhang, Tongqian; Meng, Xinzhu; Zhang, Tonghua

    2017-07-01

    Taking into account of both white and colored noises, a stochastic mathematical model with impulsive toxicant input is formulated. Based on this model, we investigate dynamics, such as the persistence and ergodicity, of plant infectious disease model with Markov conversion in a polluted environment. The thresholds of extinction and persistence in mean are obtained. By using Lyapunov functions, we prove that the system is ergodic and has a stationary distribution under certain sufficient conditions. Finally, numerical simulations are employed to illustrate our theoretical analysis.