(CP1) - Magnetic Flux Emergence from the Solar Interior to the Corona.

The activity in the visible layers of the Sun is driven by the emergence of magnetic field from its interior, involving the traversal of domains that span a vast range of physical parameters. Understanding this process is an extremely challenging problem. The SOLAIRE network is developing realistic 3D computer simulations of the emergence of magnetic flux through the photospheric layers and the chromosphere into the corona and carrying out coordinated observations of flux emergence processes for comparison with our model results. Magnetohydrodynamic (MHD) models are being extended to include upper convective layers, radiative transfer modelling (as flux traverses from optically thick to thin atmospheric layers), and realistic reconnective interaction between emerging and pre-existing complex field structures.

The solar magnetic activity cycle, the magnetic and thermal structure of the solar atmosphere and spectacular eruptive phenomena (flares, coronal mass ejections) are all determined or significantly influenced by processes of magnetic flux emergence. They have far-reaching consequences that are felt in the interplanetary medium and the planets (including the Earth).


Figure 1: Flux emergence in the Sun - Extreme UltraViolet image taken with the EIT telescope onboard the SOHO satellite (ESA) showing bright coronal loops at the site of flux emergence.
Figure 2: Flux emergence in the Sun - White-light image of magnetic regions at the photosphere which coincide with the footpoints of loops like those on Figure 1.