Publication Date:
2019-01-23
Description:
Much of the discussion on possible dynamical mechanism of spiral pattern creation in large number of observed galaxies relies on theoretical work, even though often many relevant physical effects are not explicitly included for the sake of simplicity in order to treat the problem analytically. In this paper we invoke similarity between dynamics of galaxies and electromagnetic plasmas to some extent (using similarity of mathematical tools and specific mechanisms), applying it to the inner region of a galaxy. The motivation to do so comes from usual problem of any spiral perturbation approach, that of singularities in the centre. We derive necessary condition for having soliton-like perturbation taking the vortex shape in the inner region of the galaxy. In order to do this we use hydrodynamical description of the region, supported by Poisson’s equation, treating the problem self-consistently and non-linearly. As a result, perturbation takes the form of two-dimensional localized soliton-vortex propagating along the azimuthal direction as a balance between non-linearity and dispersion. Such a solution can be subject of dissipative effects that can destroy vortex pair and create spiral pattern with different shapes (barred and non-barred), as it was observed in many of plasma experiments and numerical simulations. Advantage of analytical non-linear localized solution, although derived under a number of assumptions, is that this solution consists controlling parameters for simulations, giving possibility to estimate efficiency of relevant mechanisms, the angular momentum and matter transport as well.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
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