Cadarache

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Daniel Clery - One of the best experts on this subject based on the ideXlab platform.

Thierry Hedde - One of the best experts on this subject based on the ideXlab platform.

  • Radiosondes – LA Toulouse – M30, Cadarache
    2020
    Co-Authors: Thierry Hedde
    Abstract:

    Measurements obtained by radio-soundings with balloons of the recovery type. The "CRA2013monthdayhour.fil" file in each RS subfolder contains the following 19 variables: TempF = GPS time (s) AltitudF = geopotential altitude (m) LatitudeF = latitude (rad) LongitudeF = longitude (rad) VEstF = east component of probe velocity (m/s) VNordF = north component of probe velocity (m/s) VVertF = vertical component of probe velocity (m/s) VHorF = horizontal wind velocity (m/s) VDirF = wind direction (deg) TaNCalF = air temperature, uncalibrated (°C) TaCalF = air temperature, calibrated (°C) TaRadF = air temperature, calibrated and corrected for radiative effect (°C) -> recommended use UNCaF = relative humidity, uncalibrated (%) UCalF = relative humidity, calibrated (%) -> recommended use PressF = pressure (Pa) GPSAltF = raw GPS altitude (m) AD_OzoneF = not used T_OzoneF = not used AD_AuxF = not used

  • KASCADE2017 – An experimental study of thermal circulations and turbulence in complex terrain
    European Geosciences Union, 2017
    Co-Authors: Eric R Pardyjak, Nipun Gunawardena, Thierry Hedde, Pierre Durand, Florian Dupuy, Pierre Rubin
    Abstract:

    The KASCADE (KAtabatic winds and Stability over Cadarache for Dispersion of Effluents) 2017 experiment was conducted during winter 2017 with the overarching objective of improving prediction of dispersion in complex terrain during stable atmospheric conditions. The experiment builds on knowledge gathered during the first KASCADE experiment conducted in 2013 (Duine et al., 2016), which provided detailed observations of the vertical structure of the atmosphere during stable conditions. In spite of this improved understanding, considerable uncertainty remains regarding the near-surface horizontal spatial and temporal variability of winds and thermodynamic variables. For this specific campaign, the general aim has been to use a large number of sensors to improve our understanding of the spatial and temporal development, evolution and breakdown of topographically driven flows. KASCADE 2017 consisted of continuous observations, which were broadened during ten Intensive Obser- vation Periods (IOPs) conducted in the Cadarache Valley located in south-eastern France from January through March 2017. The Cadarache Valley is a relatively small valley (6 km x 1 km) with modest slopes and elevation differences between the valley floor and nearby peaks (∼100 m). The valley is embedded in the larger Durance Valley drainage system leading to multi-scale flow interactions. During the winter, winds are light and stably stratified leading to thermal circulations as well as complex near-surface atmospheric layering that impacts dispersion of contaminants. The continuously operating instrumentation deployed included mean near surface (2-m) and sub-surface observations from 12 low-cost Local Energy-budget Measurement Stations (LEMS), four sonic anemometer masts, one full surface flux station, sodar measurements at two locations, wind and temperature measurements from a tall 110 m tower, and two additional met stations. During IOPs, additional deployments included a low-cost tethered balloon temperature profiler as well as regular (every 3 hours) radiosoundings (including recoverable and reusable probes). The presentation will provide an overview of the experiment and several interesting “first-results.” First results will include data characterizing highly-regular nocturnal horizontal wind meandering and associated turbulence statistics. In addition, we present data on the development of strong near surface stable stratification hours before sunset.

  • A Simple Method Based on Routine Observations to Nowcast Down-Valley Flows in Shallow, Narrow Valleys
    Journal of Applied Meteorology and Climatology, 2016
    Co-Authors: Gert-jan Duine, Thierry Hedde, Pierre Roubin, Pierre Durand
    Abstract:

    AbstractA simple relation to diagnose the existence of a thermally driven down-valley wind in a shallow (100 m deep) and narrow (1–2 km wide) valley based on routine weather measurements has been determined. The relation is based on a method that has been derived from a forecast verification principle. It consists of optimizing a threshold of permanently measured quantities to nowcast the thermally driven Cadarache (southeastern France) down-valley wind. Three parameters permanently observed at a 110-m-high tower have been examined: the potential temperature difference between the heights of 110 and 2 m, the wind speed at 110 m, and a bulk Richardson number. The thresholds are optimized using the wind observations obtained within the valley during the Katabatic Winds and Stability over Cadarache for the Dispersion of Effluents (KASCADE) field experiment, which was conducted in the winter of 2013. The highest predictability of the down-valley wind at the height of 10 m (correct nowcasting ratio of 0.90) wa...

  • radiosondes la toulouse m30 Cadarache
    2015
    Co-Authors: Thierry Hedde
    Abstract:

    Measurements obtained by radio-soundings with balloons of the recovery type. The "CRA2013monthdayhour.fil" file in each RS subfolder contains the following 19 variables: TempF = GPS time (s) AltitudF = geopotential altitude (m) LatitudeF = latitude (rad) LongitudeF = longitude (rad) VEstF = east component of probe velocity (m/s) VNordF = north component of probe velocity (m/s) VVertF = vertical component of probe velocity (m/s) VHorF = horizontal wind velocity (m/s) VDirF = wind direction (deg) TaNCalF = air temperature, uncalibrated (°C) TaCalF = air temperature, calibrated (°C) TaRadF = air temperature, calibrated and corrected for radiative effect (°C) -> recommended use UNCaF = relative humidity, uncalibrated (%) UCalF = relative humidity, calibrated (%) -> recommended use PressF = pressure (Pa) GPSAltF = raw GPS altitude (m) AD_OzoneF = not used T_OzoneF = not used AD_AuxF = not used

L Svensson - One of the best experts on this subject based on the ideXlab platform.

  • experimental results from the Cadarache 1 mv test bed with singap accelerators
    Nuclear Fusion, 2006
    Co-Authors: L Svensson, H P L De Esch, D Boilson, R Hemsworth, A Krylov
    Abstract:

    A prototype negative ion accelerator, based on a pre-accelerator normally used for positive ion acceleration, was used on the Cadarache MV negative ion beam facility up to 2004. Even though this accelerator demonstrated the feasibility of SINgle GAP, SINGle APerture (SINGAP) accelerators it was not possible to produce beams with the optical quality required for ITER. A new 'ITER-like' accelerator, which is a scaled down version of the ITER SINGAP accelerator, has been built and installed on the Cadarache 1 MV test bed. The objective of the 'ITER-like' is to demonstrate reliable D− beam acceleration as close as possible to 1 MeV with a current density j− ≈ 200 A m−2 with the beam optics required for ITER, i.e. a beamlet divergence of ≤7 mrad and beamlet steering within ±2 mrad of that specified. High voltage hold-off tests have been performed and 940 kV has been held without breakdowns. Beams up to 850 keV (D−, 15 A m−2) were obtained after four weeks of experiments and the highest current density that has been obtained so far is 150 A m−2 (D−, 580 keV, 23 mA for one beamlet). The required beam optics for ITER has been obtained at near perveance match (at 120 A m−2 D−, 727 keV, 18.5 mA for one beamlet), but a larger than expected halo has been measured.

  • first simulations of the Cadarache singap experiments
    PRODUCTION AND NEUTRALIZATION OF NEGATIVE IONS AND BEAMS: Ninth International Symposium on the Production and Neutralization of Negative Ions and Beam, 2002
    Co-Authors: H P L De Esch, P Massmann, D Boilson, R Hemsworth, L Svensson
    Abstract:

    The SINGAP (SINGle APerture ‐ SINgle GAP) acceleration concept is a simplified alternative to the multi‐aperture, multi‐grid acceleration of the ITER Neutral Beam reference design. Our project aims to demonstrate reliable multi‐second acceleration of a D− beam to 1 MeV (∼100 mA, 200 A/m2), relevant to the ITER Neutral Beam Injection requirements and to validate the predictions of the simulation codes used to design the SINGAP accelerator for ITER. The present campaign achieved (911 keV, 30A/m2) and (600 keV, 60 A/m2) D− beams. The highest space charge effects have been obtained with 400 keV, 50 A/m2 D−, which, although still a factor of 2.5 below the ITER value for space charge, is beginning to test the space charge aspects of the codes. Simulation results are compared with the experimental data for a variety of cases.

  • the Cadarache 1 mv porcelain singap bushing
    Symposium On Fusion Technology, 2001
    Co-Authors: P Massmann, H P L De Esch, R Hemsworth, T Inoue, L Svensson
    Abstract:

    The 1 MV bushing is considered as one of the most technically challenging components of the ITER neutral beam injectors, necessitating the design and manufacture of large ceramic insulators beyond the range of current industrial production. The ITER radiation environment and the fact that the bushing forms part of the tritium barrier demand a component of great reliability and safety. An R&D task has been launched for the fabrication of a prototype bushing based on the SINgle GAP, SINGle APerture (SINGAP) 1 MeV accelerator being developed in the EU. We present the design of this prototype, which is to be tested at Cadarache, and compare it with the SINGAP bushing proposed for the ITER injectors.

A Krylov - One of the best experts on this subject based on the ideXlab platform.

  • experimental results from the Cadarache 1 mv test bed with singap accelerators
    Nuclear Fusion, 2006
    Co-Authors: L Svensson, H P L De Esch, D Boilson, R Hemsworth, A Krylov
    Abstract:

    A prototype negative ion accelerator, based on a pre-accelerator normally used for positive ion acceleration, was used on the Cadarache MV negative ion beam facility up to 2004. Even though this accelerator demonstrated the feasibility of SINgle GAP, SINGle APerture (SINGAP) accelerators it was not possible to produce beams with the optical quality required for ITER. A new 'ITER-like' accelerator, which is a scaled down version of the ITER SINGAP accelerator, has been built and installed on the Cadarache 1 MV test bed. The objective of the 'ITER-like' is to demonstrate reliable D− beam acceleration as close as possible to 1 MeV with a current density j− ≈ 200 A m−2 with the beam optics required for ITER, i.e. a beamlet divergence of ≤7 mrad and beamlet steering within ±2 mrad of that specified. High voltage hold-off tests have been performed and 940 kV has been held without breakdowns. Beams up to 850 keV (D−, 15 A m−2) were obtained after four weeks of experiments and the highest current density that has been obtained so far is 150 A m−2 (D−, 580 keV, 23 mA for one beamlet). The required beam optics for ITER has been obtained at near perveance match (at 120 A m−2 D−, 727 keV, 18.5 mA for one beamlet), but a larger than expected halo has been measured.

  • latest results from the Cadarache 1 mv singap experiment
    Symposium On Fusion Technology, 2003
    Co-Authors: Lennart Svensson, H P L De Esch, D Boilson, R Hemsworth, A Krylov, P Massmann
    Abstract:

    Abstract The SINGle Aperture—SINgle GAP (SINGAP) acceleration concept has been developed as a simplified alternative to the Multi-Aperture, Multi-Grid (MAMuG) acceleration of the ITER Neutral Beam reference design. The objective of the present experiments is to demonstrate reliable multi-second acceleration of a D − beam to 1 MeV (∼100 mA, 200 A/m 2 ), relevant to the ITER neutral beam injection (NBI) requirements. During the previous studies it has been demonstrated that the SINGAP concept works and good quality 860 keV H − beams (43 mA, 1 s) and 630 keV D − beams (106 mA, 1 s) have been produced. In the present R&D programme another attempt has been made to reach the full beam energy and increase the extracted beam current density with a refurbished 1 MV epoxy insulator/bushing. Refurbishment had become necessary after the top two of the nine epoxy rings making up the insulator had been perforated and carbonised due to high voltage discharges. The best results achieved during the present campaign are 914 keV D − beams (58 mA, 1 s) with a D − current density of 30 A/m 2 and 600 keV D − beams (76 mA, 1 s) with a D − current density of 70 A/m 2 . These results are world records. The beam optics is largely as expected from the modelling with the Vector Fields OPERA 3D code.

Alain Simonin - One of the best experts on this subject based on the ideXlab platform.

  • Experimental study of the characteristics of D− and H− beams produced by a multi‐hole multi‐ampere accelerator at energies up to 105 keV
    AIP Conference Proceedings, 2008
    Co-Authors: Jérôme Paméla, Alain Simonin, M Fumelli, F. Jequier, Masaya Hanada, Yoshikazu Okumura, Kazuhiro Watanabe
    Abstract:

    The acceleration of D− and H− beams has been studied at energies of up to 105 keV, with currents of the order of 2 A, in multi‐second pulses. The optimum extraction voltage has been studied as a function of the beam energy and current. The perveance of the negative ion accelerator has been measured over a wide range of operating conditions with H− and D− beams. The experimental results have been compared to beam optics calculations performed with the SLACAD negative ion code developed at Cadarache: a good agreement has been found. Strong perturbations of negative ion beamlet trajectories have been evidenced in the case of large gap, large aspect ratio accelerators. A comparison between merged beamlets and multi‐hole accelerators has been performed. The observed linear increase of the stray accelerated electron current with the extraction voltage has been explained by simulation with a Monte‐Carlo code developed at Cadarache.

  • negative ion based neutral beam development activities at Cadarache
    AIP Conference Proceedings (American Institute of Physics); (United States), 2008
    Co-Authors: Jérôme Paméla, M Fumelli, Claudine Jacquot, F. Jequier, Ronald S Hemsworth, Henk J Hopman, Alain Simonin
    Abstract:

    The work in the field of negative ions at Cadarache aims at a coherent D− beam development in view of the needs of future magnetic fusion experiments. An overview of recent activities is first given: (i) during the recent collaboration with JAERI, 2.2 A, 100 keV, D− long pulse beams have been produced and extensively studied at Cadarache; (ii) the production of negative ions from the Pagoda source is now under study; (iii) two important ITER NB related studies have been conducted, the conceptual study of a 1 MV, 15 A power supply and the design of a 1 MV, 4 A D− beamline and test bed. The future experimental studies, which constitute the main elements of the European strategy in neutral beam development for magnetic fusion applications are the following: (i) the application for financial support in EC has been made for a 1 MeV 0.1 A D− beam acceleration experiment, which is projected to be carried out in 1994; (ii) a new test bed MANTIS for multi‐ampere D− source development will also be established, cons...

  • Results of the Cadarache 1 MeV D− “SINGAP” Experiment
    Fusion Technology 1996, 1997
    Co-Authors: J. Bucalossi, Clara Desgranges, M Fumelli, P Massmann, Jérôme Paméla, Alain Simonin
    Abstract:

    The objective of the experiment is to demonstrate the acceleration of a long pulse 100 m A D− ion beam in a simplified electrostatic accelerator concept. In contrast to the ITER injector reference design, multiple beamlets are pre-accelerated to about 50 keV, then merged and post-accelerated to 1 MeV into one SINGle APerture (at high voltage) using one SINgle GAP (“SINGAP”). The beam is dumped onto a uni-directional thermal conductivity CFC graphite target allowing infrared-calorimetric beam profile measurements. The experiment is supported by 3d beam trajectory calculations. Conditioning without beam to 1 MV was achieved after the first 10 days of operation. This required only 35 min of integrated voltage on-time. During voltage application, an intense field-emitted electron current (up to 120 mA of “dark current”) is observed. This current can be strongly reduced by conditioning and pressure increase. H− beams of good quality were produced at a level of 910 keV, 40 mA, 1 s pulse. The only problem encountered was the perforation by breakdowns of one of the 9 insulator rings (epoxy) which constitute the 1 MV bushing. After repairing this insulator, the high voltage operation could be restarted without major difficulties. The damage of the insulator is due to a defect in the manufacturing process and does not impair the qualities of the SINGAP concept.

  • results of the Cadarache 1 mev d singap experiment
    Symposium On Fusion Technology, 1997
    Co-Authors: J. Bucalossi, Clara Desgranges, M Fumelli, P Massmann, Jérôme Paméla, Alain Simonin
    Abstract:

    The objective of the experiment is to demonstrate the acceleration of a long pulse 100 m A D− ion beam in a simplified electrostatic accelerator concept. In contrast to the ITER injector reference design, multiple beamlets are pre-accelerated to about 50 keV, then merged and post-accelerated to 1 MeV into one SINGle APerture (at high voltage) using one SINgle GAP (“SINGAP”). The beam is dumped onto a uni-directional thermal conductivity CFC graphite target allowing infrared-calorimetric beam profile measurements. The experiment is supported by 3d beam trajectory calculations. Conditioning without beam to 1 MV was achieved after the first 10 days of operation. This required only 35 min of integrated voltage on-time. During voltage application, an intense field-emitted electron current (up to 120 mA of “dark current”) is observed. This current can be strongly reduced by conditioning and pressure increase. H− beams of good quality were produced at a level of 910 keV, 40 mA, 1 s pulse. The only problem encountered was the perforation by breakdowns of one of the 9 insulator rings (epoxy) which constitute the 1 MV bushing. After repairing this insulator, the high voltage operation could be restarted without major difficulties. The damage of the insulator is due to a defect in the manufacturing process and does not impair the qualities of the SINGAP concept.

  • negative ion beam development at Cadarache invited
    Review of Scientific Instruments, 1996
    Co-Authors: Alain Simonin, J. Bucalossi, Clara Desgranges, M Fumelli, P Massmann, Jérôme Paméla, R Trainham, Claudine Jacquot, Yu. I. Belchenko
    Abstract:

    Neutral beam injection (NBI) is one of the candidates for plasma heating and current drive in the new generation of large magnetic fusion devices (ITER). In order to produce the required deuterium atom beams with energies of 1 MeV and powers of tens of MW, negative D− ion beams are required. For this purpose, multiampere D− beam production and 1 MeV electrostatic acceleration is being studied at Cadarache. The SINGAP experiment, a 1 MeV 0.1 A D− multisecond beam accelerator facility, has recently started operation. It is equipped with a Pagoda ion source, a multiaperture 60 keV preaccelerator and a 1 MV 120 mA power supply. The particular feature of SINGAP is that the postaccelerator merges the 60 keV beamlets, aiming at accelerating the whole beam to 1 MeV in a single gap. The 1 MV level was obtained in less than 2 weeks, the accumulated voltage on‐time of being ∼22 min. A second test bed MANTIS, is devoted to the development of multiampere D− sources. It is capable of driving discharges with current up ...

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