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Title: Explicit approximations to estimate the perturbative diffusivity in the presence of convectivity and damping. II. Semi-infinite cylindrical approximations

In this paper, a number of new explicit approximations are introduced to estimate the perturbative diffusivity (χ), convectivity (V), and damping (τ) in a cylindrical geometry. For this purpose, the harmonic components of heat waves induced by localized deposition of modulated power are used. The approximations are based upon the heat equation in a semi-infinite cylindrical domain. The approximations are based upon continued fractions, asymptotic expansions, and multiple harmonics. The relative error for the different derived approximations is presented for different values of frequency, transport coefficients, and dimensionless radius. Moreover, it is shown how combinations of different explicit formulas can yield good approximations over a wide parameter space for different cases, such as no convection and damping, only damping, and both convection and damping. This paper is the second part (Part II) of a series of three papers. In Part I, the semi-infinite slab approximations have been treated. In Part III, cylindrical approximations are treated for heat waves traveling towards the center of the plasma.
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [4] ; ;  [1] ;  [5] ;  [3] ;  [6] ;  [4] ;  [3]
  1. National Institute for Fusion Science, 322 Oroshi-cho, Toki-city, Gifu 509-5292 (Japan)
  2. (JSPS) (Japan)
  3. (Netherlands)
  4. FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research, Association EURATOM- FOM, Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein (Netherlands)
  5. Department of Mechanical Engineering, Dynamics and Control group, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands)
  6. Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8580 (Japan)
Publication Date:
OSTI Identifier:
22410272
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 11; Other Information: (c) 2014 EURATOM; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; APPROXIMATIONS; CONTINUED FRACTIONS; CONVECTION; CYLINDRICAL CONFIGURATION; DAMPING; HEAT; PLASMA