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New Approach for Analyzing Dynamical Processes on the Surface of Photospheric Vortex Tubes

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Version 2 2024-06-05, 01:41
Version 1 2022-03-31, 09:07
journal contribution
posted on 2024-06-05, 01:41 authored by Y Aljohani, V Fedun, I Ballai, SSA Silva, Sergiy ShelyagSergiy Shelyag, G Verth
Abstract The majority of studies on multi-scale vortex motions employ a two-dimensional geometry by using a variety of observational and numerical data. This approach limits the understanding the nature of physical processes responsible for vortex dynamics. Here, we develop a new methodology to extract essential information from the boundary surface of vortex tubes. 3D high-resolution magneto-convection MURaM numerical data has been used to analyze photospheric intergranular velocity vortices. The Lagrangian averaged vorticity deviation technique was applied to define the centers of vortex structures and their boundary surfaces based on the advection of fluid elements. These surfaces were mapped onto a constructed envelope grid that allows the study of the key plasma parameters as functions of space and time. Quantities that help in understanding the dynamics of the plasma, e.g., Lorentz force, pressure force, and plasma-β were also determined. Our results suggest that, while density and pressure have a rather global behavior, the other physical quantities undergo local changes, with their magnitude and orientation changing in space and time. At the surface, the mixing in the horizontal direction is not efficient, leading to appearance of localized regions with higher/colder temperatures. In addition, the analysis of the MHD Poynting flux confirms that the majority of the energy is directed in the horizontal direction. Our findings also indicate that the pressure and magnetic forces that drive the dynamics of the plasma on vortex surfaces are unbalanced and therefore the vortices do not rotate as a rigid body.

History

Journal

Astrophysical Journal

Volume

928

Article number

ARTN 3

Pagination

1-15

Location

Chicago, IL

Open access

  • Yes

ISSN

0004-637X

eISSN

1538-4357

Language

English

Publication classification

C1 Refereed article in a scholarly journal

Issue

1

Publisher

University of Chicago Press