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

M. van Berkel, G.M.D. Hogeweij, N. Tamura, Heiko J. Zwart, S. Inagaki, M.R. de Baar, K. Ida

    Research output: Contribution to journalArticleAcademicpeer-review

    5 Citations (Scopus)


    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.
    Original languageUndefined
    Pages (from-to)112508
    Number of pages12
    JournalPhysics of plasmas
    Issue number11
    Publication statusPublished - Nov 2014


    • Semi-infinite slab
    • Transport coefficient
    • EWI-25785
    • Asymptotic expansion
    • Cylinders (shapes)
    • Cylindrical domain
    • Continued fraction
    • Multiple harmonics
    • Harmonic components
    • Engineering controlled terms: Climatology
    • Engineering main heading: Damping
    • METIS-309922
    • IR-94464
    • Cylindrical geometry

    Cite this