On Kolmogorov- and Kraichnan-type spectra due to the reflection Alfvén waves
| Autor: | Paulo Gil, N. L. Isaeva, Luís Campos |
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| Rok vydání: | 1999 |
| Předmět: | |
| Zdroj: | Scopus-Elsevier |
| ISSN: | 1089-7674 1070-664X |
| DOI: | 10.1063/1.873543 |
| Popis: | Alfven waves are considered in a radially inhomogeneous medium under a radial background magnetic field: In order for the latter to be divergence free, the magnetic field strength must decay like the inverse square of the distance; for the radial dependence of the mass density an arbitrary inverse power of the distance is assumed. The Alfven wave equation is solved exactly in terms of Bessel functions, and the properties of the solutions are examined: (i) for small radial distances, when the reflection of waves by the inhomogeneity of the medium depends on frequency, thereby changing their spectrum; (ii) for large radial distances, when the ray approximation holds, the spectrum no longer changes and the equipartition of kinetic and magnetic energies is true; (iii) for intermediate radial distances the evolution between the limits (i) and (ii) is illustrated by plotting (Figs. 1 to 4) the wave forms of the velocity and magnetic field perturbations, for a variety of wave periods. The present problem involve... |
| Databáze: | OpenAIRE |
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