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Title: ICRH of JET and LHD Majority Ions at their Fundamental Cyclotron Frequency

Authors:
 [1];  [2];  [2];  [3];  [4];  [4];  [4];  [4];  [5];  [4];  [4];  [3];  [4];  [4];  [4];  [6];  [7];  [8];  [8];  [8] more »;  [1];  [1];  [9];  [9];  [9];  [9];  [9];  [1];  [10];  [10];  [10];  [10];  [10];  [10];  [10];  [10];  [10];  [6];  [10] « less
  1. Troitsk Institute of Nuclear Physics (TRINITI), Russia
  2. ERM-KMS, Association EURATOM-Belgian State, Brussels, Belgium
  3. Laboratory for Plasma Physics-ERM/KMS (LPP-ERM/KMS), Brussels, Belgium
  4. EURATOM / UKAEA, UK
  5. Russian Research Center, Kurchatov Institute, Moscow, Russia
  6. ORNL
  7. Ghent University, Belgium
  8. ENEA, Frascati
  9. Uppsala University, Uppsala, Sweden
  10. National Institute for Fusion Science, Toki, Japan
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1122699
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: 17th Topical Conference on Radio Frequency Power in Plasmas, Clearwater, FL, USA, 20070507, 20070509
Country of Publication:
United States
Language:
English

Citation Formats

Krasilnikov, A. V., Van Eester, D., Lerche, E., Ongena, J., Mailloux, J., Stamp, M. F., Jachmich, S., Leggate, H., Vdovin, V., Walden, A., Mayoral, M.-L., Bonheure, G., Santala, M., Kiptily, V., Popovichev, S., Biewer, Theodore M, Crombe, K., Esposito, Basilio, Marocco, D., Riva, M., Kaschuck, Yu A, Amosov, V. N., Ericsson, G., Giacomelli, L., Hellesen, C., Hjalmarsson, A., Kallne, J., JET EFDA Task Force Heating and LHD Team,, Isobe, M., Nishiura, M., Saito, K. D., Seki, T., Mutoh, T., Kumazawa, R., Takeiri, Y., Osakabe, M., Goto, M., Murakami, Masanori, and Goncharov, P.. ICRH of JET and LHD Majority Ions at their Fundamental Cyclotron Frequency. United States: N. p., 2007. Web.
Krasilnikov, A. V., Van Eester, D., Lerche, E., Ongena, J., Mailloux, J., Stamp, M. F., Jachmich, S., Leggate, H., Vdovin, V., Walden, A., Mayoral, M.-L., Bonheure, G., Santala, M., Kiptily, V., Popovichev, S., Biewer, Theodore M, Crombe, K., Esposito, Basilio, Marocco, D., Riva, M., Kaschuck, Yu A, Amosov, V. N., Ericsson, G., Giacomelli, L., Hellesen, C., Hjalmarsson, A., Kallne, J., JET EFDA Task Force Heating and LHD Team,, Isobe, M., Nishiura, M., Saito, K. D., Seki, T., Mutoh, T., Kumazawa, R., Takeiri, Y., Osakabe, M., Goto, M., Murakami, Masanori, & Goncharov, P.. ICRH of JET and LHD Majority Ions at their Fundamental Cyclotron Frequency. United States.
Krasilnikov, A. V., Van Eester, D., Lerche, E., Ongena, J., Mailloux, J., Stamp, M. F., Jachmich, S., Leggate, H., Vdovin, V., Walden, A., Mayoral, M.-L., Bonheure, G., Santala, M., Kiptily, V., Popovichev, S., Biewer, Theodore M, Crombe, K., Esposito, Basilio, Marocco, D., Riva, M., Kaschuck, Yu A, Amosov, V. N., Ericsson, G., Giacomelli, L., Hellesen, C., Hjalmarsson, A., Kallne, J., JET EFDA Task Force Heating and LHD Team,, Isobe, M., Nishiura, M., Saito, K. D., Seki, T., Mutoh, T., Kumazawa, R., Takeiri, Y., Osakabe, M., Goto, M., Murakami, Masanori, and Goncharov, P.. Mon . "ICRH of JET and LHD Majority Ions at their Fundamental Cyclotron Frequency". United States. doi:.
@article{osti_1122699,
title = {ICRH of JET and LHD Majority Ions at their Fundamental Cyclotron Frequency},
author = {Krasilnikov, A. V. and Van Eester, D. and Lerche, E. and Ongena, J. and Mailloux, J. and Stamp, M. F. and Jachmich, S. and Leggate, H. and Vdovin, V. and Walden, A. and Mayoral, M.-L. and Bonheure, G. and Santala, M. and Kiptily, V. and Popovichev, S. and Biewer, Theodore M and Crombe, K. and Esposito, Basilio and Marocco, D. and Riva, M. and Kaschuck, Yu A and Amosov, V. N. and Ericsson, G. and Giacomelli, L. and Hellesen, C. and Hjalmarsson, A. and Kallne, J. and JET EFDA Task Force Heating and LHD Team, and Isobe, M. and Nishiura, M. and Saito, K. D. and Seki, T. and Mutoh, T. and Kumazawa, R. and Takeiri, Y. and Osakabe, M. and Goto, M. and Murakami, Masanori and Goncharov, P.},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}

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  • Results of the experimental studies of ICRH at the fundamental cyclotron frequency of the majority deuterons in JET plasmas with near-tangential deuteron neutral beam injection (NBI) are presented. 1D, 2D and 3D ICRH modeling indicated that several ITER relevant mechanisms of heating may occur simultaneously in this heating scheme: fundamental ion cyclotron resonance heating of majority and beam D ions, impurity ion heating and electron heating due to Landau damping and TTMP. These mechanisms were studied in JET experiments with a {approx}90% D, 5% H plasma including traces of Be and Ar. Up to 2MW of ICRH power was appliedmore » at 25 MHz to NBI heated plasmas. In most of the discharges the toroidal magnetic field strength was 3.3T, but in one it was equal to 3.6T. The E{sub +} component of the electric field governs the ion cyclotron heating of not too fast particles. The Doppler shifted RF absorption of the beam deuterons away from the cold resonance at which E{sub +} is small was exploited to enhance the RF power absorption efficiency. Fundamental ICRH experiments were also carried out in LHD hydrogen plasma with high energy hydrogen NBI. ICRH was performed at 38MHz with injected power <1 MW. The effect of fundamental ICRH was clearly demonstrated in both machines.« less
  • Ion Cyclotron Resonance Heating (ICRH) powers of up to 17 MW have been coupled to JET limiter plasmas. The plasma stored energy has reached 7 MJ with 13 MW of RF in 5 MA discharges with Z/sub eff/ = 2. When I/sub p//B/sub /phi// = 1 MA/T the stored energy can be 50% greater than the Goldston L mode scaling. This is due to transient stabilisation of sawteeth (up to 3 s) and to a significant energy content in the minority particles accelerated by RF (up to 30% of the total stored energy). Central temperatures of T/sub e/ - 11more » keV and T/sub i/ = 8 keV have been reached with RF alone. (He/sup 3/)D fusion experiments have given a 60 kW fusion yield (fusion rate of 2 /times/ 10/sup 16/ s/sup /minus/1/ in the form of energetic fast particles (14.7 MeV(H), 3.6 MeV(He/sup 4/)) in agreement with modelling. When transposing the same calculation to a (D)T scenario, Q is predicted to be between 0.l2 and 0.8 using plasma parameters already achieved. For the first time, a peaked density profile generated by pellet injection could be reheated and sustained by ICRF for 1.2 s. Electron heat transport in the central region is reduced by a factor 2 to 3. The fusion product n/sub io//tau//sub E/T/sub io/ reaches 2.2 /times/ 10/sup 20/ m/sup /minus/3//center dot/s/center dot/kev in 3 MA discharges which is a factor of 2.3 times larger than with normal density profile. 18 refs., 13 figs., 3 tabs.« less
  • Recent experiments in JET have provided information on the potential of using majority RF heating schemes in large plasmas. Adopting a wide range of available diagnostics, the plasma behaviour was monitored. The main results of the experiments are that--due to the poor antenna coupling at low frequency, the low (Ohmic) plasma temperature and the reduced RF electric field amplitude near the ion-cyclotron resonance layer of the majority ions--ICRH alone is barely capable of heating the plasma. On the other hand, when preheating the plasma using neutral beam injection, the wave-plasma coupling is noticeably improved and considerable plasma heating, followed bymore » increased neutron yield were observed in several diagnostics. This effect is not only attributed to the lower collisionality of the pre-heated plasma but also to the Doppler-shifted IC absorption of the fast beam ions. By studying the response of the plasma to sudden changes in the RF power level, the experimental power deposition profiles were determined and compared to theoretical predictions. The numerical modelling was done adopting a coupled wave/Fokker-Planck code that enables accounting for the non-Maxwellian distributions of the RF heated particles and the injected beam ions in the wave equation, and for the actual local RF fields in the Fokker-Planck description. The theoretical results confirm the experimental finding that the beam ions do play a crucial role in this heating scheme.« less
  • Heating single ion species plasmas with ICRF is a challenging task: Fundamental ion cyclotron heating (w = w{sub ci}) suffers from the adverse polarization of the RF electric fields near the majority cyclotron resonance while second harmonic heating (w = 2w{sub ci}) typically requires pre-heating of the plasma ions to become efficient. Recently, w = 2w{sub ci} ICRF heating was tested in JET-ILW hydrogen plasmas in the absence of neutral beam injection (L-mode). Despite the lack of pre-heating, up to 6MW of ICRF power were coupled to the plasma leading to a transition to H-mode for P{sub ICRH}>5MW in mostmore » discharges. Heating efficiencies between 0.65-0.85 were achieved as a combination of the low magnetic field adopted (enhanced finite Larmor radius effects) and the deliberate slow rise of the ICRF power, allowing time for a fast ion population to gradually build-up leading to a systematic increase of the wave absorptivity. Although fast ion tails are a common feature of harmonic ICRF heating, the N=2 majority heating features moderate tail energies (<500keV) except at very low plasma densities (n{sub e0}<3x10{sup 19}/m{sup 3}), where fast H tails in the MeV range developed and fast ion losses became significant, leading to enhanced plasma wall interaction. The main results of these experiments will be reported.« less
  • Previous studies in PLT using charge-exchange, edge probe, and fusion product diagnostics all indicate that ICRF tends to produce energetic trapped particles whose banana tips are near the resonance layer. A bounce-averaged quasilinear operator which predicts this ''resonance localization'' has been implemented in a Fokker-Planck code in order to make detailed comparisons with measurements. Good agreement is found with data from the horizontally-scanning, mass-resolving, charge-exchange analyzer, although the RF power profile seems to be broader than expected. We have recently observed a deuterium tail during hydrogen minority heating. The shape of this tail and its scaling with RF power agreemore » well with the quasilinear theory. These measurements indicate that as much as 30% of the central RF power goes into direct second harmonic deuterium heating.« less