Poster abstract

Two-step Emergence of the Magnetic Flux Sheet from the Solar Convection Zone
S. Toriumi and T. Yokoyama


Emerging magnetic fluxes in the solar convection zone are thought to be responsible for the formation of active regions. We perform two-dimensional MHD simulations of the flux emergence from the solar interior to the corona. The flux sheet is initially located deep (-20,000 km) in the adiabatically stratified convection zone and is perturbed to trigger the Parker instability. The flux rises through the convection zone, but stops just beneath the strongly sub-adiabatic photosphere/chromosphere. As the magnetic pressure gradient increases, the flux becomes unstable to the Parker instability and begins to emerge to the atmosphere again. We show the results of the simulations based on this 'two-step emergence' model and make a comparison with results of the thin-flux-tube approximation (e.g. Moreno-Insertis et al. 1995).