Dynamics of convection around axisymmetric magnetic flux tubes

Gert Botha ,    University of Leeds

 Pores and sunspots are some of the magnetic features observed on the surface of the solar photosphere.
In this presentation numerical models are used to study idealised pores and sunspots.
Vertical flux tubes are placed in a compressible convecting photosphere in an axisymmetric cylindrical box with radius up to 4 times its depth [1].
 The PDEs solved are those considered by Hurlburt and Toomre [2].
Large convection cells form in the photosphere that push magnetic field lines towards the centre (at $r=0$).
We found convection cells with clockwise and anti-clockwise rotations - which may respectively give an indication to processes associated
    with pores and the perumbral flow around sunspots.
In this presentation the structure of the flows is investigated in terms of the values of
the physical parameters of the problem and the possible influence of the numerical boundaries of the domain.
   
    [1] N.E. Hurlburt & A.M. Rucklidge, 2000, MNRAS 314, 793-806.
    [2] N.E. Hurlburt & J. Toomre, 1988, ApJ, 327, 920-32.