Nonlinear Vortex Structures in Obliquely Rotating Fluid

Kopp, M. I.; Тур, А. В.; Yanovsky, Vladimir

doi:10.4236/ojfd.2015.54032

Cited by 10 publications

(36 citation statements)

References 10 publications

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“…In the case of non-electroconductive fluid ( = 0)  with the temperature gradient ( 0) T   we obtain the same results as in [50]. In the limit of non-electroconductive ( = 0)  and homogeneous fluid ( =0) T  we obtain the results of [46]. To study this dynamo model, it is necessary at first to consider the evolution of small perturbations and then to examine the nonlinear effects.…”

Section: Equations For Large-scale Fieldssupporting

confidence: 64%

“…The development of this large-scale instability in obliquely rotating fluid gives rise to nonlinear large-scale helical structures of Beltrami vortex type, or to localized kinks with internal helical structure. In [47] the new hydrodynamic  -effect found in [46] was generalized to the case of electroconductive fluid. The corresponding large-scale instability leads to the generation of LSVS and magnetic fields.…”

Section: Eejp 1 (2020)mentioning

confidence: 98%

“…The question naturally arises about the possibility of generation of large-scale vortices (hydrodynamic and magnetic) in rotating media under the action of a small-scale force with zero helicity 0 0 = 0 F rotF   . The example of LSVS generation in a rotating incompressible fluid is found in [46]. The development of this large-scale instability in obliquely rotating fluid gives rise to nonlinear large-scale helical structures of Beltrami vortex type, or to localized kinks with internal helical structure.…”

Section: Eejp 1 (2020)mentioning

confidence: 99%

“…Both instabilities occur when the vector of angular rotation velocity   is deflected from the vertical axis OZ . Unlike the case of a homogeneous medium[46][47], the combined effects of rotarion and stratification of the medium (at heating from below) give rise to an essential amplification of the large-scale perturbations.This phenomenon becomes especially noticeable at the parameters of the medium 3  D and 5…”

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confidence: 98%

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Nonlinear Dynamo in Obliquely Rotating Stratified Electroconductive Fluid in an Uniformly Magnetic Field

Kopp

Тур

Kulik

et al. 2020

EEJP

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In this paper, we investigated a new large-scale instability that arises in an obliquely rotating convective electrically conducting fluid in an external uniform magnetic field with a small-scale external force with zero helicity. This force excites small-scale velocity oscillations with a small Reynolds number. Using the method of multiscale asymptotic expansions, we obtain the nonlinear equations for vortex and magnetic disturbances in the third order of the Reynolds number. It is shown that the combined effects of the Coriolis force and the small external forces in a rotating conducting fluid possible large-scale instability. The linear stage of the magneto-vortex dynamo arising as a result of instabilities of -effect type is investigated. The mechanism of amplification of large-scale vortex disturbances due to the development of the hydrodynamic - effect taking into account the temperature stratification of the medium is studied. It was shown that a «weak» external magnetic field contributes to the generation of large-scale vortex and magnetic perturbations, while a «strong» external magnetic field suppresses the generation of magnetic-vortex perturbations. Numerical methods have been used to find stationary solutions of the equations of a nonlinear magneto-vortex dynamo in the form of localized chaotic structures in two cases when there is no external uniform magnetic field and when it is present.

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Section: Equations For Large-scale Fieldssupporting

confidence: 64%

Section: Eejp 1 (2020)mentioning

confidence: 98%

Section: Eejp 1 (2020)mentioning

confidence: 99%

mentioning

confidence: 98%

See 2 more Smart Citations

Nonlinear Dynamo in Obliquely Rotating Stratified Electroconductive Fluid in an Uniformly Magnetic Field

Kopp

Тур

Kulik

et al. 2020

EEJP

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“…Obviously, the question arises of the possibility of the generation of large-scale vortex fields in a rotating media under the influence of small-scale forces with zero helicity. An example of the generation of LSVS in a rotating incompressible fluid was found in [21]. It was also shown that the expansion of a large-scale instability in an inclined rotating fluid generates nonlinear large-scale helical vortex structures or localized Beltrami vortices within the internal helical structure.…”

Section: Introductionmentioning

confidence: 96%

Nonlinear Vortex Structures Driven by Small-Scale Non-helical Forces in Obliquely Rotating Stratified Fluids

2021

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We study a new type of large-scale instability in obliquely rotating stratifi ed fl uids with small-scale nonhelical turbulence. The small-scale turbulence is generated by the external force with zero helicity and low Reynolds number. The theory uses the method of multiscale asymptotic expansions. The nonlinear equations for large-scale motions are obtained in the third order of perturbation theory. We consider a linear instability and stationary nonlinear modes. Solutions in the form of nonlinear Beltrami waves and localized vortex structures such as kinks of a new type are obtained.

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Generation of large-scale magnetic-vortex structures in stratified magnetized plasma by a small-scale force

Kopp,

Yanovsky

2024

Physics of Plasmas

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In this study, within the framework of electron magnetohydrodynamics, taking into account thermomagnetic phenomena, we obtained a new large-scale instability of the α-effect type, which ensures the generation of large-scale vortex and magnetic fields. This instability occurs in a flat layer of temperature-stratified plasma under the influence of an external uniform magnetic field inclined relative to the layer, combined with a small-scale external force having zero helicity. The external force is presented as a source of small-scale oscillations in the speed of electrons with a low Reynolds number R≪1. The presence of a small parameter in the system allowed us to apply the method of multiscale asymptotic expansions to derive nonlinear equations for vortex and magnetic disturbances. These equations were obtained in third-order Reynolds number. Using solutions for the velocity field in zero order in Reynolds number, we determined the average helicity H=v0·rotv0¯ and its relation to the α-effect. A necessary condition for the generation of average helicity in stratified magnetized plasma is the inclined orientation of the external magnetic field and the presence of a small-scale force. A new effect related to the influence of thermal force (the Nernst effect) on large-scale instability is discussed. It is shown that an increase in the Nernst parameter leads to a decrease in the amplification factor α and thereby prevents the development of large-scale instability. With the help of numerical analysis, stationary solutions to the vortex and magnetic dynamo equations in the form of localized structures like nonlinear waves of the Beltrami were obtained.

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Nonlinear Vortex Structures in Obliquely Rotating Fluid

Cited by 10 publications

References 10 publications

Nonlinear Dynamo in Obliquely Rotating Stratified Electroconductive Fluid in an Uniformly Magnetic Field

Nonlinear Dynamo in Obliquely Rotating Stratified Electroconductive Fluid in an Uniformly Magnetic Field

Nonlinear Vortex Structures Driven by Small-Scale Non-helical Forces in Obliquely Rotating Stratified Fluids

Generation of large-scale magnetic-vortex structures in stratified magnetized plasma by a small-scale force

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