Extended investigations of isotope effects on ECRH plasma in LHD

K. Tanaka (Corresponding Author), M. Nakata, Y. Ohtani, T. Tokuzawa, H. Yamada, F. Warmer, M. Nunami, S. Satake, T. Tala, T. Tsujimura, Y. Takemura, T. Kinoshita, H. Takahashi, M. Yokoyama, R. Seki, H. Igami, Y. Yoshimura, S. Kubo, T. Shimozuma, T. AkiyamaI. Yamada, R. Yasuhara, H. Funaba, M. Yoshinuma, K. Ida, M. Goto, G. Motojima, M. Shoji, S. Masuzaki, C. A. Michael, L. N. Vacheslavov, M. Osakabe, T. Morisaki, LHD experiment group

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Abstract

Isotope effects of ECRH plasma in LHD were investigated in detail. A clear difference of transport and turbulence characteristics in H and D plasmas was found in the core region, with normalized radius ρ < 0.8 in high collisionality regime. On the other hand, differences of transport and turbulence were relatively small in low collisionality regime. Power balance analysis and neoclassical calculation showed a reduction of the anomalous contribution to electron and ion transport in D plasma compared with H plasma in the high collisionality regime. In core region, density modulation experiments also showed more reduced particle diffusion in D plasma than in H plasma, in the high collisionality regime. Ion scale turbulence was clearly reduced at ρ < 0.8 in high collisionality regime in D plasma compared with H plasma. The gyrokinetic linear analyses showed that the dominant instability ρ = 0.5 and 0.8 were ion temperature gradient mode (ITG). The linear growth rate of ITG was reduced in D plasma than in H plasma in high collisionality regime. This is due to the lower normalized ITG and density gradient. More hollowed density profile in D plasma is likely to be the key control parameter. Present analyses suggest that anomalous process play a role to make hollower density profiles in D plasma rather than neoclassical process. Electron scale turbulence were also investigated from the measurements and linear gyrokinetic simulations.

Original languageEnglish
Article number024006
JournalPlasma Physics and Controlled Fusion
Volume62
Issue number2
Early online date16 Dec 2019
DOIs
Publication statusPublished - Jan 2020
MoE publication typeA4 Article in a conference publication
Event46th European Physical Society Conference on Plasma Physics, EPS 2019 - Milan, Italy
Duration: 8 Jul 201912 Jul 2019

Keywords

  • energy transport
  • isotope effect
  • particle transport
  • stellarator
  • turbulence

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    Tanaka, K., Nakata, M., Ohtani, Y., Tokuzawa, T., Yamada, H., Warmer, F., Nunami, M., Satake, S., Tala, T., Tsujimura, T., Takemura, Y., Kinoshita, T., Takahashi, H., Yokoyama, M., Seki, R., Igami, H., Yoshimura, Y., Kubo, S., Shimozuma, T., ... LHD experiment group (2020). Extended investigations of isotope effects on ECRH plasma in LHD. Plasma Physics and Controlled Fusion, 62(2), [024006]. https://doi.org/10.1088/1361-6587/ab5bae