New magnetohydrodynamic model for close binary stars: Applicability for moderate magnetic fields

Жилкин, А. Г.; Bisikalo, D. V.; Ustyugov, V. A.

doi:10.1063/1.4818850

Cited by 12 publications

(7 citation statements)

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“…A fairly dense grid (256 × 256 cells) in a two dimensional computational domain was used for the solution: (see the table 1), and the angle θ 0 was defined by the relation 2 sin θ 0 = 1 − R min /R max . The numerical code was based on a Godunov-type finite-difference scheme of high order of accuracy (see, e.g., [29]). The computations were carried out at the computer clusters of the Institute of Astronomy and the Joint Supercomputer Center of the Russian Academy of Sciences.…”

Section: The Modelmentioning

confidence: 99%

Features of the accretion in the EX Hydrae system: Results of numerical simulation

Isakova¹,

Жилкин²,

Бисикало³

et al. 2017

Astron. Rep.

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A two dimensional numerical model in the axisymmetric approximation that describes the flow structure in the magnetosphere of the white dwarf in the EX Hya system has been developed. Results of simulations show that the accretion in EX Hya proceeds via accretion columns, that are not closed and have curtain-like shapes. The thickness of the accretion curtains depends only weakly on the thickness of the accretion disk. This thickness developed in the simulations does not agree with observations. It is concluded that the main reason for the formation of thick accretion curtains in the used model is the assumption that the magnetic field penetrates fully into the plasma of the disk. An analysis based on simple estimates shows that a diamagnetic disk that fully or partially shields the magnetic field of the star may be a more attractive explanation for the observed features of the accretion in EX Hya.

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Section: The Modelmentioning

confidence: 99%

Features of the accretion in the EX Hydrae system: Results of numerical simulation

Isakova¹,

Жилкин²,

Бисикало³

et al. 2017

Astron. Rep.

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“…The dependencies of the radiative heating function Γ and the cooling function Λ on the temperature T have fairly complex forms [41,42,43,44]. Therefore, in our numerical model, we used linear approximations for these functions in the vicinity of the equilibrium temperature, 8 782 K [29,45,46,47], which corresponds to the effective temperatures of all three sources of thermal radiation in the AE Aquarii system. The term 2(v v v × Ω Ω Ω) in the equation of motion (25) describes the Coriolis force.…”

Section: Description Of the Modelmentioning

confidence: 99%

“…The decay time scale for the transverse velocity t w is determined by wave dissipation of the magnetic field in the diffusion layer. We applied the 3D parallel numerical code [27,29,46,47] in our MHD numerical simulation. This code is based on the Godunov-type difference scheme with the high order of accuracy.…”

Section: Description Of the Modelmentioning

confidence: 99%

Features of the matter flows in the peculiar cataclysmic variable AE Aquarii

et al. 2016

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Abstract.The structure of plasma flows in close binary systems in which one of the components is a rapidly rotating magnetic white dwarf is studied. The main example considered is the AE Aquarii system; the spin period of the white dwarf is about a factor of 1000 shorter than the orbital period, and the magnetic field on the white dwarf surface is of order of 50 MG. The mass transfer in this system was analyzed via numerical solution of the system of MHD equations. These computations show that the magnetic field of the white dwarf does not significantly influence the velocity field of the material in its Roche lobe in the case of laminar flow regime, so that the field does not hinder the formation of a transient disk (ring) surrounding the magnetosphere. However, the efficiency of the energy and angular momentum exchange between the white dwarf and the surrounding material increases considerably with the development of turbulent motions in the matter, resulting in its acceleration at the magnetospheric boundary and further escape from the system at a high rate. The time scales of the transition of the system between the laminar and turbulent modes are close to those of the AE Aqr transition between its quiet and active phases.

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“…However, the results of calculations [18] have demonstrated that this model is sufficiently universal. With an appropriate choice of parameters (for example, the parameter determining the efficiency of the wave turbulence), this model also well describes the flow structure in the case of weak magnetic fields.…”

Section: Description Of the Modelmentioning

confidence: 99%

A numerical model for accretion in intermediate polars with dipolar magnetic fields

2015

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A three-dimensional numerical model for an accretion process investigation in the magnetosphere of a white dwarf in magnetic cataclysmic variables is developed. The model assumes that the white dwarf has a dipole magnetic field with its symmetry axis inclined to the rotation axis. The model is based on the equations of modified MHD, that describe the mean flow parameters in the wave MHD turbulence. Diffusion of the magnetic field and radiative heating and cooling are taken into account. The suitability of the model is confirmed by modeling the accretion in a typical intermediate polar. The computations show that a magnetosphere forms around the accretor, with the accretion occurring via columns. The accretion columns have a curtain-like shape, and arc-shaped zones of energy release form on the surface of the white dwarf in the magnetic poles area as a result of the matter infall.

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New magnetohydrodynamic model for close binary stars: Applicability for moderate magnetic fields

Cited by 12 publications

References 0 publications

Features of the accretion in the EX Hydrae system: Results of numerical simulation

Features of the accretion in the EX Hydrae system: Results of numerical simulation

Features of the matter flows in the peculiar cataclysmic variable AE Aquarii

A numerical model for accretion in intermediate polars with dipolar magnetic fields

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