295 research outputs found
Three-dimensional magnetohydrodynamic simulation of the solar magnetic flux emergence: Parametric study on the horizontal divergent flow
Solar active regions are formed through the emergence of magnetic flux from
the deeper convection zone. Recent satellite observations have shown that a
horizontal divergent flow (HDF) stretches out over the solar surface just
before the magnetic flux appearance. The aims of this study are to investigate
the driver of the HDF and to see the dependency of the HDF on the parameters of
the magnetic flux in the convection zone. We conduct three-dimensional
magnetohydrodynamic (3D MHD) numerical simulations of the magnetic flux
emergence and vary the parameters in the initial conditions. An analytical
approach is also taken to explain the dependency. The horizontal gas pressure
gradient is found to be the main driver of the HDF. The maximum HDF speed shows
positive correlations with the field strength and twist intensity. The HDF
duration has a weak relation with the twist, while it shows negative dependency
on the field strength only in the case of the stronger field regime. Parametric
dependencies analyzed in this study may allow us to probe the structure of the
subsurface magnetic flux by observing properties of the HDF.Comment: 7 pages, 5 figures, 1 table, accepted for publication in Astronomy &
Astrophysic
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