Roles of Viscous Membrane in an MHD Self-Organization

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In order to exarnine the role of' the energy inptrt in the fornaation of' an ordered strvrcturein a semi-open system, we have developed a non1ine?'tr simulation model in which the energyinput time and the dyn?rtnic respotase titne of the system are changeable. For this purpose, aviscous naeraabrane (botmndary layer) is placed between a steady convection sotrrce and a nonlinearfeed back systern in which ;+ dissip?rtion-free taaagnetohydrodynarnic plasnaa and a resistive weaklyionized platsnaa are cotrpled. It is found that the thin viscous raaernbrane acts to be a high-passfilter that can play a role of 21 fixed boundary for the do cornponent btrt a free bovrndary for theac cornponent. Bec;'vuse of this char;tcter of the uaaettabrane, when the ratio of' the ac energy inputtime to the dynamic response tirtae of' the systetn becotnes relatively large, the membrarae acts torelease the fltrcttration (ac) energy f'rorn the syste?au. Consequently, the positive feedback efl'ectfor the fluctuation is weakened and the structtzre fornaation is prevented as the ratio exceeds acertain critical V2llL1C. It is 2llSO ['ound that the viscotus naetnbr;tne ])l21VS another important rolein self'-organization, nataaely, that 21S the strtrctvrre fornuation is highly progressed, the dc energyinptrt rate is atrtononaotrsly ad.jtrsted so as to keep the developed strtrcttrre in a steady form.
1997-07-15