Shrinkage of tokamak current channel by external ergodization

Hattori, Kazuo; Seike, Yasushi; Yoshida, Zensho; Hamaguchi, Satoshi; Yamada, H.; Suzuki, N.; Itami, K.; Kamada, Y.; Inoue, N.; Uchida, T.

doi:10.1016/0022-3115(84)90147-8

Cited by 11 publications

(11 citation statements)

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“…[4][5][6][7][8][9]), in Tore Supra (Refs. [10][11][12][13][14][15][16][17]) and in a number of small-size tokamaks (in JFT-2M ( [18,19]), CSTN-II ( [20,21]), HYBTOK-II ( [22]), TBR-1 [23], TCABR ( [24]), and other small fusion devices ( [25,26]).…”

Section: Introductionmentioning

confidence: 99%

Modelling of magnetic field structure of the Ergodic Divertor of Tore Supra and comparison to the Dynamic Ergodic Divertor of TEXTOR

Abdullaev,

Van Rompuy,

Finken

et al. 2008

Preprint

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An analytical model previously developed to study the structure of the magnetic field for the TEXTOR-DED [S.S. Abdullaev et al. Phys. Plasmas, 6, 153 (1999)] is applied to the similar study of the Ergodic Divertor of Tore Supra tokamak [Ph. Ghendrih, Plasma Phys. Control. Fusion, 38, 1653(1996]. The coil configuration of ED Tore Supra consists of six modules equidistantly located along the toroidal direction on the low-field-side of the torus with given toroidal and poloidal extensions. The Hamiltonian formulation of field line equations in straight-field-line coordinates (Boozer coordinates) and the computationally efficient mapping method for integration of the Hamiltonian field line equations are used to study the magnetic field structure in the ED. Asymptotical formulas for the perturbation magnetic field created by the ED coils are obtained and the spectrum of magnetic perturbations is analyzed and compared with the one of the TEXTOR-DED. The structure of ergodic and laminar zones are studied by plotting Poincaré sections, so-called laminar plots (contour plots of wall to wall connection lengths) and magnetic footprints. The radial profiles of field line diffusion coefficients are calculated for different perturbation currents and it is found that for the Tore Supra case in the ergodic zone the numerical field line diffusion coefficients perfectly follow the quasilinear formula for smaller perturbation currents although the situation is different for the maximum perturbation current.

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Section: Introductionmentioning

confidence: 99%

Modelling of magnetic field structure of the Ergodic Divertor of Tore Supra and comparison to the Dynamic Ergodic Divertor of TEXTOR

Abdullaev,

Van Rompuy,

Finken

et al. 2008

Preprint

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“…Within the plasma core, both improvement and degradation of confinement were observed; a link with a modified naturally occurring magnetohydrodynamic (MHD) tearing mode activity was suggested as an explanation. On the small tokamak TORIUT-4M [21 ], an externally applied m = 3, n = 1 helical field was used to ergodize the internally generated m = 2, n = 1 islands. Magnetic probe measurements showed a shrinkage of the plasma current channel.…”

Section: Introductionmentioning

confidence: 99%

Electron thermal confinement studies with applied resonant fields on TEXT

McCool

Wootton

Aydemir³

et al. 1989

Nucl. Fusion

127

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Externally applied magnetic fields are used on the Texas Experimental Tokamak (TEXT) to study the possibility of controlling the particle, impurity and heat fluxes at the plasma edge. Fields with toroidal mode number n = 2 or 3 and multiple poloidal mode numbers m (dominantly m = 7) are used, with a poloidally and toroidally averaged ratio of radial to toroidal field components 〈|br/Bø〉 ≅0. 1%. Calculations show that it is possible to produce mixed islands and stochastic regions at the plasma edge (r/a ≥ 0.8) without affecting the interior. The expected magnetic field structure is described and experimental evidence of the existence of this structure is presented. The edge electron temperature decreases with increasing 〈|br/Bø〉, while interior values are not significantly affected. The implied increase in edge electron thermal diffusivity is compared with theoretical expectations and is shown to agree with applicable theories to within a factor of three.

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“…However, city shrinkage, as the antithesis of urbanization, is an ongoing extreme phenomenon not only in developed countries, but also emerging in some fast-urbanizing countries [2,3]. City shrinkage is characterized by population loss, economic downturn, and inefficient land use [4][5][6]. Especially in the developed world, with a background of globalization and de-industrialization, many large cities are considered shrinking cities or will be shrinking cities [7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Spatiotemporal Differences in Determinants of City Shrinkage Based on Semiparametric Geographically Weighted Regression

et al. 2019

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City shrinkage, as an ongoing worldwide phenomenon, is an issue for urban planning and regional development. City shrinkage is remarkable in Japan, with over 85% of municipalities experiencing population loss from 2005 to 2015. As Japan’s society ages and with its low fertility rate, city shrinkage has had a tremendous negative effect on economic development and urban planning. Understanding the spatial dependence and spatial heterogeneity of city shrinkage and its determinants is essential for ensuring the sustainable development of a city or region. In this study, a semiparametric geographically weighted regression (SGWR) model was adopted to explore the spatiotemporal differences in determinants of city shrinkage. The results reveal that the SGWR model incorporating the global and local variables is more interpretive compared to ordinary least squares and geographically weighted regression models in exploring the correlates of city shrinkage. We found the spatial dependence and heterogeneity of shrinking cities resulted from demographic, economy, and social factors, and revealed low fertility, the ageing population, and enterprise change ratio influenced city shrinkage in different regions at different times in Japan, whereas foreign population ratio, industry structure, and social welfare had global impacts. The findings provide useful information for understanding city shrinkage at global and local scales.

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Shrinkage of tokamak current channel by external ergodization

Cited by 11 publications

References 1 publication

Modelling of magnetic field structure of the Ergodic Divertor of Tore Supra and comparison to the Dynamic Ergodic Divertor of TEXTOR

Modelling of magnetic field structure of the Ergodic Divertor of Tore Supra and comparison to the Dynamic Ergodic Divertor of TEXTOR

Electron thermal confinement studies with applied resonant fields on TEXT

Spatiotemporal Differences in Determinants of City Shrinkage Based on Semiparametric Geographically Weighted Regression

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