Statistical theory of subcritically-excited strong turbulence in inhomogeneous plasmas. I

Sanae I. Itoh, Kimitaka Itoh

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23 Citations (Scopus)


A statistical description is developed for a self-sustained subcritical turbulence in inhomogeneous plasmas. Interchange mode in the presence of inhomogeneous magnetic field, which reveals a submarginal strong turbulence, is considered. Nonlinear dispersion relation is extended to a Langevin equation for a dressed test mode, in which nonlinear interactions are kept as renormalized drag and random self noise. Based upon the assumption that the random noise has a faster time scale, the solutions are obtained for the fluctuation level, decorrelation rate, auto- and cross-correlation functions and spectrum. They are expressed as nonlinear functions of non-equilibrium parameters like gradient. Extended fluctuation-dissipation theorem (Einstein relation) is described as statistical relations. Then the Langevin equation is reformulated into a Fokker-Planck equation of the probability distribution function. The steady state probability function is solved. Imposing the constraint of the self-noise, the power-law distribution with respect to the fluctuation amplitude is obtained in the tail of the distribution function.

Original languageEnglish
Pages (from-to)1891-1906
Number of pages16
Journaljournal of the physical society of japan
Issue number6
Publication statusPublished - Jun 1999

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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