7 results on '"Dumortier, Pierre"'
Search Results
2. RF Sheath-Enhanced Plasma Surface Interaction Studies using Beryllium Optical Emission Spectroscopy in JET ITER-Like Wall
- Author
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Christopher Klepper C., Colas Laurent, Křivská Alena, Bobkov Volodymyr, Jacquet Philippe, Delabie Ephrem, Giroud Carine, Kirov Krassimir, Lasa Ane, Lerche Ernesto, Dumortier Pierre, Durodié Frederic, and Firdaouss Mehdi
- Subjects
Physics ,QC1-999 - Abstract
A dedicated study on JET-ILW, deploying two types of ICRH antennas and spectroscopic observation spots at two outboard, beryllium limiters, has provided insight on long-range (up to 6m) RFenhanced plasma-surface interactions (RF-PSI) due to near-antenna electric fields. To aid in the interpretation of optical emission measurements of these effects, the antenna near-fields are computed using the TOPICA code, specifically run for the ITER-like antenna (ILA); similar modelling already existed for the standard JET antennas (A2). In the experiment, both antennas were operated in current drive mode, as RF-PSI tends to be higher in this phasing and at similar power (∼0.5 MW). When sweeping the edge magnetic field pitch angle, peaked RF-PSI effects, in the form of 2-4 fold increase in the local Be source,are consistently measured with the observation spots magnetically connect to regions of TOPICAL-calculated high near-fields, particularly at the near-antenna limiters. It is also found that similar RF-PSI effects are produced by the two types of antenna on similarly distant limiters. Although this mapping of calculated near-fields to enhanced RF-PSI gives only qualitative interpretion of the data, the present dataset is expected to provide a sound experimental basis for emerging RF sheath simulation model validation.
- Published
- 2017
- Full Text
- View/download PDF
3. Reinstated JET ICRF ILA: Overview and Results
- Author
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Dumortier Pierre, Durodié Frédéric, Blackman Trevor, Helou Walid, Jacquet Philippe, Lerche Ernesto, Monakhov Igor, Noble Craig, Bobkov Volodymyr, Goulding Richard, Kaufman Michael, and Van Eester Dirk
- Subjects
Physics ,QC1-999 - Abstract
The works undertaken to reinstate the JET ICRF ILA are reviewed. The vacuum matching capacitors were replaced, an extensive calibration of all the measurements in the RF circuit was carried out, new simulation tools were created and new control algorithms were implemented for the – toroidal and poloidal – phase control of the array as well as for the matching of the second stage. A review of the contribution of the reinstated ILA to the JET programme during the last campaigns is given showing namely that the new controls allowed extending the range of the operation to lower (29MHz) and higher (51MHz) frequencies than previously achieved and allowed more flexible and reliable operation. Operation with coupled power levels up to 2.8MW and voltages up to 40kV was achieved. ILA results on plasma are discussed and emphasis is given to the features of interest for ITER.
- Published
- 2017
- Full Text
- View/download PDF
4. Recent H majority inverted radio frequency heating scheme experiments in JET-ILW
- Author
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Van Eester Dirk, Lerche Ernesto, Kazakov Yevgen, Jacquet Philippe, Baranov Yuri, Bobkov Volodymyr, Crombé Kristel, Czarnecka Agata, Dumont Remi, Dumortier Pierre, Eriksson Jacob, Giacomelli Luca, Giroud Carine, Goniche Marc, Hellesen Carl, Kiptily Vasily, Krawczyk Natalia, Koskela Tuomas, Nave Filomena, Nocente Massimo, Ongena Jef, Santala Marko, Salewski Mirko, Schneider Mireille, and Weisen Henri
- Subjects
Physics ,QC1-999 - Abstract
Inverted 3He and D ion cyclotron minority heating scenarios were recently tested in JET-ILW. They confirm the good heating efficiency at low concentrations of ∼3%. The 3He minority heating scheme is only modestly affected by the change from a carbon (JET-C) to a Beryllium (JET-ILW) wall but unlike what was the case in JET-C, the intrinsic Be ions D-like particles in terms of charge-over-mass ratio do not prevent the D (or 4He) minority regime from being exploited. Direct and indirect evidence of the existence of fast particle subpopulations was found in both cases.
- Published
- 2017
- Full Text
- View/download PDF
5. Electromagnetic simulations of JET ICRF ITER-like antenna with TOPICA and SSWICH asymptotic codes
- Author
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Křivská Alena, Bobkov Volodymyr, Colas Laurent, Dumortier Pierre, Durodié Frédéric, Lerche Ernesto, Jacquet Philippe, Jacquot Jonathan, Klepper Christopher, and Milanesio Daniele
- Subjects
Physics ,QC1-999 - Abstract
Multi-megawatt Ion Cyclotron Range of Frequencies (ICRF) heating is routinely used in the JET tokamak. To increase the ICRF heating power available from the A2 antennas, the ICRF ITER-Like Antenna (ILA) was reinstalled for the 2015 JET ITER-like wall experimental campaign. The application of high levels of ICRF power typically results in increased plasma wall interaction which leads to the observation of enhanced influx of metallic impurities in the plasma edge. It is assumed that the impurity production is mainly driven by the parallel component of the Radio-Frequency (RF) antenna electric near-field, E// (parallel to the confinement magnetic field of the tokamak), that is rectified in a thin boundary layer (RF sheath). Torino Polytechnic Ion Cyclotron Antenna (TOPICA) code was used to compute E// field maps in front of the ILA and between its poloidal limiters in the presence of plasma using measured density profiles and various antenna feedings. E// field maps calculated between the poloidal limiters were used to estimate the poloidal distribution of RF-sheath Direct Current (DC) potential in this private region of the ILA and make relative comparison of various antenna electrical settings. For this purpose we used the asymptotic version of the Self-consistent Sheaths and Waves for Ion Cyclotron Heating Slow-Wave (SSWICH-SW) code. These estimations can help to study the formation of RF sheaths around the antenna and even at distant locations (∼3m away).
- Published
- 2017
- Full Text
- View/download PDF
6. Recent H majority inverted radio frequency heating scheme experiments in JET-ILW
- Author
-
Van Eester, D, Lerche, E, Kazakov, Y, Jacquet, P, Baranov, Y, Bobkov, V, Crombã©, K, Czarnecka, A, Dumont, R, Dumortier, P, Eriksson, J, Giacomelli, L, Giroud, C, Goniche, M, Hellesen, C, Kiptily, V, Krawczyk, N, Koskela, T, Nave, F, Nocente, M, Ongena, J, Santala, M, Salewski, M, Schneider, M, Weisen, H, Van Eester, Dirk, Lerche, Ernesto, Kazakov, Yevgen, Jacquet, Philippe, Baranov, Yuri, Bobkov, Volodymyr, Crombé, Kristel, Czarnecka, Agata, Dumont, Remi, Dumortier, Pierre, Eriksson, Jacob, Giacomelli, Luca, Giroud, Carine, Goniche, Marc, Hellesen, Carl, Kiptily, Vasily, Krawczyk, Natalia, Koskela, Tuomas, Nave, Filomena, Nocente, Massimo, Ongena, Jef, Santala, Marko, Salewski, Mirko, Schneider, Mireille, Weisen, Henri, Van Eester, D, Lerche, E, Kazakov, Y, Jacquet, P, Baranov, Y, Bobkov, V, Crombã©, K, Czarnecka, A, Dumont, R, Dumortier, P, Eriksson, J, Giacomelli, L, Giroud, C, Goniche, M, Hellesen, C, Kiptily, V, Krawczyk, N, Koskela, T, Nave, F, Nocente, M, Ongena, J, Santala, M, Salewski, M, Schneider, M, Weisen, H, Van Eester, Dirk, Lerche, Ernesto, Kazakov, Yevgen, Jacquet, Philippe, Baranov, Yuri, Bobkov, Volodymyr, Crombé, Kristel, Czarnecka, Agata, Dumont, Remi, Dumortier, Pierre, Eriksson, Jacob, Giacomelli, Luca, Giroud, Carine, Goniche, Marc, Hellesen, Carl, Kiptily, Vasily, Krawczyk, Natalia, Koskela, Tuomas, Nave, Filomena, Nocente, Massimo, Ongena, Jef, Santala, Marko, Salewski, Mirko, Schneider, Mireille, and Weisen, Henri
- Abstract
Inverted3He and D ion cyclotron minority heating scenarios were recently tested in JET-ILW. They confirm the good heating efficiency at low concentrations of â¼3%. The3He minority heating scheme is only modestly affected by the change from a carbon (JET-C) to a Beryllium (JET-ILW) wall but unlike what was the case in JET-C, the intrinsic Be ions D-like particles in terms of charge-over-mass ratio do not prevent the D (or4He) minority regime from being exploited. Direct and indirect evidence of the existence of fast particle subpopulations was found in both cases
- Published
- 2017
7. RF Sheath-Enhanced Plasma Surface Interaction Studies using Beryllium Optical Emission Spectroscopy in JET ITER-Like Wall.
- Author
-
Klepper, C. Christopher, Colas, Laurent, Křivská, Alena, Bobkov, Volodymyr, Jacquet, Philippe, Delabie, Ephrem, Giroud, Carine, Kirov, Krassimir, Lasa, Ane, Lerche, Ernesto, Dumortier, Pierre, Durodié, Frederic, and Firdaouss, Mehdi
- Subjects
RADIO frequency ,PLASMA gases ,BERYLLIUM ,EMISSION spectroscopy ,MAGNETIC fields ,FIELD theory (Physics) - Abstract
A dedicated study on JET-ILW, deploying two types of ICRH antennas and spectroscopic observation spots at two outboard, beryllium limiters, has provided insight on long-range (up to 6m) RF enhanced plasma-surface interactions (RF-PSI) due to near-antenna electric fields. To aid in the interpretation of optical emission measurements of these effects, the antenna near-fields are computed using the TOPICA code, specifically run for the ITER-like antenna (ILA); similar modelling already existed for the standard JET antennas (A2). In the experiment, both antennas were operated in current drive mode, as RF-PSI tends to be higher in this phasing and at similar power (~0.5 MW). When sweeping the edge magnetic field pitch angle, peaked RF-PSI effects, in the form of 2-4 fold increase in the local Be source, are consistently measured with the observation spots magnetically connect to regions of TOPICAL-calculated high near-fields, particularly at the near-antenna limiters. It is also found that similar RF-PSI effects are produced by the two types of antenna on similarly distant limiters. Although this mapping of calculated near-fields to enhanced RF-PSI gives only qualitative interpretion of the data, the present dataset is expected to provide a sound experimental basis for emerging RF sheath simulation model validation. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
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