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JET (3He)–D scenarios relying on RF heating: survey of selected recent experiments

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Abstract
Recent JET experiments have been devoted to the study of (He-3)-D plasmas involving radio frequency (RF) heating. This paper starts by discussing the RF heating efficiency theoretically expected in such plasmas, covering both relevant aspects of wave and of particle dynamics. Then it gives a concise summary of the main conclusions drawn from recent experiments that were either focusing on studying RF heating physics aspects or that were adopting RF heating as a tool to study plasma behavior. Depending on the minority concentration chosen, different physical phenomena are observed. At very low concentration (X[He-3] < 1%), energetic tails are formed which trigger MHD activity and result in loss of fast particles. Alfven cascades were observed and gamma ray tomography indirectly shows the impact of sawtooth crashes on the fast particle orbits. Low concentration (X[He-3] < 10%) favors minority heating while for X[He-3] >> 10% electron mode conversion damping becomes dominant. Evidence for the Fuchs et al standing wave effect (Fuchs et al 1995 Phys. Plasmas 2 1637-47) on the absorption is presented. RF induced deuterium tails were observed in mode conversion experiments with large X[He-3] (approximate to 18%). As tentative modeling shows, the formation of these tails can be explained as a consequence of wave power absorption by neutral beam particles that efficiently interact with the waves well away from the cold D cyclotron resonance position as a result of their substantial Doppler shift. As both ion and electron RF power deposition profiles in (He-3)-D plasmas are fairly narrow-giving rise to localized heat sources-the RF heating method is an ideal tool for performing transport studies. Various of the experiments discussed here were done in plasmas with internal transport barriers (ITBs). ITBs are identified as regions with locally reduced diffusivity, where poloidal spinning up of the plasma is observed. The present know-how on the role of RF heating for impurity transport is also briefly summarized.
Keywords
INTERNAL TRANSPORT BARRIERS, RF, WAVE MODE CONVERSION, ION-CYCLOTRON, nuclear fusion, plasma heating, ALFVEN-WAVE, IMPURITY TRANSPORT, ASDEX UPGRADE, LOWER-HYBRID, PLASMAS, TOKAMAKS, FREQUENCY

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Chicago
Van Eester, D, E Lerche, Y Andrew, TM Biewer, A Casati, Kristel Crombé, E de la Luna, et al. 2009. “JET (3He)–D Scenarios Relying on RF Heating: Survey of Selected Recent Experiments.” Plasma Physics and Controlled Fusion 51 (4).
APA
Van Eester, D, Lerche, E., Andrew, Y., Biewer, T., Casati, A., Crombé, K., de la Luna, E., et al. (2009). JET (3He)–D scenarios relying on RF heating: survey of selected recent experiments. PLASMA PHYSICS AND CONTROLLED FUSION, 51(4).
Vancouver
1.
Van Eester D, Lerche E, Andrew Y, Biewer T, Casati A, Crombé K, et al. JET (3He)–D scenarios relying on RF heating: survey of selected recent experiments. PLASMA PHYSICS AND CONTROLLED FUSION. 2009;51(4).
MLA
Van Eester, D et al. “JET (3He)–D Scenarios Relying on RF Heating: Survey of Selected Recent Experiments.” PLASMA PHYSICS AND CONTROLLED FUSION 51.4 (2009): n. pag. Print.
@article{971335,
  abstract     = {Recent JET experiments have been devoted to the study of (He-3)-D plasmas involving radio frequency (RF) heating. This paper starts by discussing the RF heating efficiency theoretically expected in such plasmas, covering both relevant aspects of wave and of particle dynamics. Then it gives a concise summary of the main conclusions drawn from recent experiments that were either focusing on studying RF heating physics aspects or that were adopting RF heating as a tool to study plasma behavior. Depending on the minority concentration chosen, different physical phenomena are observed. At very low concentration (X[He-3] < 1%), energetic tails are formed which trigger MHD activity and result in loss of fast particles. Alfven cascades were observed and gamma ray tomography indirectly shows the impact of sawtooth crashes on the fast particle orbits. Low concentration (X[He-3] < 10%) favors minority heating while for X[He-3] >> 10% electron mode conversion damping becomes dominant. Evidence for the Fuchs et al standing wave effect (Fuchs et al 1995 Phys. Plasmas 2 1637-47) on the absorption is presented. RF induced deuterium tails were observed in mode conversion experiments with large X[He-3] (approximate to 18%). As tentative modeling shows, the formation of these tails can be explained as a consequence of wave power absorption by neutral beam particles that efficiently interact with the waves well away from the cold D cyclotron resonance position as a result of their substantial Doppler shift. As both ion and electron RF power deposition profiles in (He-3)-D plasmas are fairly narrow-giving rise to localized heat sources-the RF heating method is an ideal tool for performing transport studies. Various of the experiments discussed here were done in plasmas with internal transport barriers (ITBs). ITBs are identified as regions with locally reduced diffusivity, where poloidal spinning up of the plasma is observed. The present know-how on the role of RF heating for impurity transport is also briefly summarized.},
  author       = {Van Eester, D and Lerche, E and Andrew, Y and Biewer, TM and Casati, A and Crombé, Kristel and de la Luna, E and Ericsson, G and Felton, R and Giacomelli, L and Giroud, C and Hawkes, NC and Hellesen, C and Hjalmarsson, A and Joffrin, E and Kallne, J and Kiptily, V and Lomas, P and Mantica, P and Marinoni, A and Mayoral, M-L and Ongena, J and Piuatti, M-E and Santala, M and Sharapov, S and Valisa, M},
  issn         = {0741-3335},
  journal      = {PLASMA PHYSICS AND CONTROLLED FUSION},
  keywords     = {INTERNAL TRANSPORT BARRIERS,RF,WAVE MODE CONVERSION,ION-CYCLOTRON,nuclear fusion,plasma heating,ALFVEN-WAVE,IMPURITY TRANSPORT,ASDEX UPGRADE,LOWER-HYBRID,PLASMAS,TOKAMAKS,FREQUENCY},
  language     = {eng},
  number       = {4},
  title        = {JET (3He)–D scenarios relying on RF heating: survey of selected recent experiments},
  url          = {http://dx.doi.org/10.1088/0741-3335/51/4/044007},
  volume       = {51},
  year         = {2009},
}

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