Radiative magnetohydrodynamic simulations of solar pores

¹ Max-Planck-Institut für Sonnensystemforschung Max-Planck-Str. 2, 37191 Katlenburg-Lindau, Germany e-mail: [camerom;schuessler;zakharov]@mps.mpg.de
² Sterrekundig Instituut, Utrecht University, Postbus 80 000, 3508 TA Utrecht, The Netherlands e-mail: A.Voegler@astro.uu.nl

Received: 22 June 2007
Accepted: 23 July 2007

Abstract

Context.Solar pores represent a class of magnetic structures intermediate between small-scale magnetic flux concentrations in intergranular lanes and fully developed sunspots with penumbrae.

Aims.We study the structure, energetics, and internal dynamics of pore-like magnetic structures by means of exploratory numerical simulations.

Methods.The MURaM code has been used to carry out several 3D radiative MHD simulations for pores of various sizes and with different boundary conditions.

Results.The general properties of the simulated pores (morphology, continuum intensity, magnetic field geometry, surrounding flow pattern, mean height profiles of temperature, pressure, and density) are consistent with observational results. No indications for the formation of penumbral structure are found. The simulated pores decay by gradually shedding magnetic flux into the surrounding pattern of intergranular downflows (“turbulent erosion”). When viewed under an angle (corresponding to observations outside solar disc center), granules behind the pore appear brightened.

Conclusions.Radiative MHD simulations capture many observed properties of solar pores.