Temperature dependence of the thermal diffusivity in high-collisionality regimes in the large helical device

J. Miyazawa, H. Yamada, S. Murakami, H. Funaba, B. J. Peterson, M. Osakabe, K. Tanaka, S. Sakakibara, S. Inagaki

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

The positive density dependence of energy confinement times, τE, as expressed in the international stellarator scaling 95 (ISS95), where ( is the line-averaged density and P is the heating power), declines in high-collisionality regimes in the large helical device experiments. In the low-collisionality regime, where parameter dependences in ISS95 agree well with the experiment, the temperature dependence of thermal diffusivity is as strong as predicted by the gyro-Bohm model and/or the neoclassical theory. As the collisionality increases to the plateau regime, the temperature dependence becomes moderate, where the thermal diffusivity is proportional to the square root of the electron temperature. Furthermore, the thermal diffusivity is inversely proportional to the magnetic field strength and the electron temperature gradient is proportional to the electron temperature in the high-collisionality regime. Compared with ISS95, the energy confinement time expected from these observations has a weaker density dependence together with mitigated power degradation: .

Original languageEnglish
Pages (from-to)801-813
Number of pages13
JournalPlasma Physics and Controlled Fusion
Volume47
Issue number6
DOIs
Publication statusPublished - Jun 1 2005
Externally publishedYes

Fingerprint

stellarators
Thermal diffusivity
Electron temperature
thermal diffusivity
electron energy
scaling
temperature dependence
Thermal gradients
Temperature
plateaus
field strength
temperature gradients
Experiments
Magnetic fields
degradation
Heating
Degradation
heating
energy
magnetic fields

All Science Journal Classification (ASJC) codes

  • Nuclear Energy and Engineering
  • Condensed Matter Physics

Cite this

Temperature dependence of the thermal diffusivity in high-collisionality regimes in the large helical device. / Miyazawa, J.; Yamada, H.; Murakami, S.; Funaba, H.; Peterson, B. J.; Osakabe, M.; Tanaka, K.; Sakakibara, S.; Inagaki, S.

In: Plasma Physics and Controlled Fusion, Vol. 47, No. 6, 01.06.2005, p. 801-813.

Research output: Contribution to journalArticle

Miyazawa, J, Yamada, H, Murakami, S, Funaba, H, Peterson, BJ, Osakabe, M, Tanaka, K, Sakakibara, S & Inagaki, S 2005, 'Temperature dependence of the thermal diffusivity in high-collisionality regimes in the large helical device', Plasma Physics and Controlled Fusion, vol. 47, no. 6, pp. 801-813. https://doi.org/10.1088/0741-3335/47/6/006
Miyazawa, J. ; Yamada, H. ; Murakami, S. ; Funaba, H. ; Peterson, B. J. ; Osakabe, M. ; Tanaka, K. ; Sakakibara, S. ; Inagaki, S. / Temperature dependence of the thermal diffusivity in high-collisionality regimes in the large helical device. In: Plasma Physics and Controlled Fusion. 2005 ; Vol. 47, No. 6. pp. 801-813.
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AU - Peterson, B. J.

AU - Osakabe, M.

AU - Tanaka, K.

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