Abstract


  FLUX EMERGENCE, SMALL FLARES, AND THE UNRESOLVED FINE STRUCTURE

  V. Hansteen, University of Oslo, viggoh@astro.uio.no

The emergence of flux through the photosphere and into the outer solar atmosphere is known to produce dynamic events in the chromosphere and corona. In this talk we will describe three-dimensional (3D) magnetohydrodynamic simulations of magnetic flux emergence in a model that spans the convection zone and into the outer solar atmosphere with the Bifrost code. This is a ''realistic'' model, in the sense that the parameters and physical effects that control the atmosphere can be used to produce diagnostics that can be directly compared with observations. The emerging flux leads to the formation of several current sheets as it rises into the modeled corona. Multiple plasmoids are ejected from the current sheets. Reconnection occurs impulsively, producing heating and fast outflows near or in the current sheet, arranged in a manner reminiscent of the CSHKP flare model, but on a much smaller scale. This includes a cusp like arcade and a flux rope in the lower atmospere underneath the current sheet. We discuss the evolution of the model and several synthetic observables. We also discuss the model's possible relevance to the so called 'unresolved fine structure' observed in the solar transition region.