Instabilities in multicomponent cold magnetized accretion disks

Nekrasov, A. K.

doi:10.1063/1.2739452

Cited by 12 publications

(16 citation statements)

References 21 publications

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“…In their turn, the neutrals also experience the collisional coupling with charged species influencing on their equilibrium velocity. Some specific cases of equilibrium have been investigated in papers by Nekrasov (2007Nekrasov ( , 2008aNekrasov ( , 2008bNekrasov ( , 2009b, where the expressions for stationary velocities of species in the gravitational field of the central mass have been found at the absence of collisions as well as with taking into account collisions for cases of weak and strong collisional coupling of neutrals with ions.…”

Section: Equilibriummentioning

confidence: 99%

“…In the papers by Nekrasov (2007Nekrasov ( , 2008aNekrasov ( , 2008bNekrasov ( , 2009aNekrasov ( , 2009b and in the present paper, we study streaming instabilities of multicomponent rotating magnetized objects, using the equations of motion and continuity for each species. From Faraday's and Ampere's laws we obtain equations for the electric field components (see Equation (15)).…”

Section: On the Resistivity In The Standard Mhdmentioning

confidence: 99%

“…In a series of papers, Nekrasov (2007Nekrasov ( , 2008aNekrasov ( , 2008bNekrasov ( , 2009aNekrasov ( , 2009b, a general theory for electromagnetic compressible streaming instabilities in multicomponent rotating magnetized objects, such as accretion disks and molecular clouds has been developed. In equilibrium of accretion disks, different background velocities of different species (electrons, ions, dust grains, and neutrals) have been found from the momentum equations with taking into account anisotropic thermal pressure and collisions of charged species with neutrals.…”

Section: Introductionmentioning

confidence: 99%

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Compressible Streaming Instabilities in Rotating Thermal Viscous Objects

Nekrasov¹

2009

ApJ

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We study electromagnetic streaming instabilities in thermal viscous regions of rotating astrophysical objects, such as protostellar and protoplanetary magnetized accretion disks, molecular clouds, their cores, and elephant trunks. The obtained results can also be applied to any regions of interstellar medium, where different equilibrium velocities between charged species can arise. We consider a weakly and highly ionized three-component plasma consisting of neutrals and magnetized electrons and ions. The vertical perturbations along the background magnetic field are investigated. The effect of perturbation of collisional frequencies due to density perturbations of species is taken into account. The growth rates of perturbations are found in a wide region of wave number spectrum for media, where the thermal pressure is larger than the magnetic pressure. It is shown that in cases of strong collisional coupling of neutrals with ions the contribution of the viscosity is negligible.

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Section: Equilibriummentioning

confidence: 99%

Section: On the Resistivity In The Standard Mhdmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Compressible Streaming Instabilities in Rotating Thermal Viscous Objects

Nekrasov¹

2009

ApJ

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“…The second term can generate the streaming instability of the hydrodynamic kind. This term does not change the order of the dispersion relation for perturbations under consideration that results in the appearance of the threshold for the absolute instability to develop (see also Nekrasov 2007).…”

Section: Dispersion Relationmentioning

confidence: 99%

“…In a series of papers (Nekrasov 2007, 2008a,b, 2009a,b), a general theory has been developed for electromagnetic compressible streaming instabilities in multicomponent rotating magnetized objects, such as accretion discs and molecular clouds. For accretion discs, the different equilibrium velocities of the different species (electrons, ions, dust grains and neutrals) have been found using momentum equations, taking into account the anisotropic thermal pressure and collisions of charged species with neutrals (Nekrasov 2008a,b, 2009b).…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic instabilities in rotating magnetized viscous objects

Nekrasov

2009

Monthly Notices of the Royal Astronomical Society

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We study electromagnetic streaming instabilities in thermal viscous regions of rotating astrophysical objects, such as, magnetized accretion disks, molecular clouds, their cores, and elephant trunks. The obtained results can also be applied to any regions of interstellar medium, where different equilibrium velocities between charged species can arise. We consider a weakly ionized multicomponent plasma consisting of neutrals and magnetized electrons, ions, and dust grains. The effect of perturbation of collisional frequencies due to density perturbations of species is taken into account. We obtain general expressions for perturbed velocities of species involving the thermal pressure and viscosity in the case in which perturbations propagate perpendicular to the background magnetic field. The dispersion relation is derived and investigated for axisymmetric perturbations. New compressible instabilities generated due to different equilibrium velocities of different charged species are found in the cold and thermal limits when the viscosity of neutrals can be neglected or is important. The viscosity of magnetized charged species is negligible for considered perturbations having wavelengths much larger than the Larmor radius of species. At the same time, the neutrals are shown to be immobile in electromagnetic perturbations when their viscosity is sufficiently large.Comment: Accepted for publication in MNRA

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Compressible streaming instabilities of warm multicomponent collisional magnetized astrophysical disks

Nekrasov

2008

Physics of Plasmas

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A general theory for instabilities of multicomponent warm magnetized accretion disks is developed using Maxwell’s equations and the equations of motion and continuity for each disk component. The compressibility, anisotropic thermal pressure, and collisions of the charged species with neutrals are taken into account. The thermal effects are involved without any simplifications. An equilibrium state is discussed. The dispersion relation is derived in the most general form for an arbitrary direction of the wave vector of perturbations and for an arbitrary strength of the thermal effects. The solutions of the dispersion relation are found in some specific case appropriated for the weakly ionized plasma in the regions of the protostellar and protoplanetary disks, where the electrons can be considered as thermal and magnetized and the ions and dust grains as cold and unmagnetized. These solutions describe new axisymmetric and nonaxisymmetric electromagnetic disk instabilities due to collisions and the difference between the stationary azimuthal velocities of different charged species.

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Instabilities in multicomponent cold magnetized accretion disks

Cited by 12 publications

References 21 publications

Compressible Streaming Instabilities in Rotating Thermal Viscous Objects

Compressible Streaming Instabilities in Rotating Thermal Viscous Objects

Electromagnetic instabilities in rotating magnetized viscous objects

Compressible streaming instabilities of warm multicomponent collisional magnetized astrophysical disks

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