Magnetic network dynamics: Activity level, feature size and anchoring depth

Laboratoire d'Astrophysique de l'Observatoire Midi-Pyrénées, 57 avenue d'Azereix, BP 826, 65008 Tarbes Cedex, France e-mail: meunier@bagn.obs-mip.fr

Received: 23 November 2004
Accepted: 16 February 2005

Abstract

A large data set of MDI magnetograms is studied in order to analyze the global dynamics of magnetic structures from network to active regions. Two complementary techniques are used: feature tracking and correlation tracking. The very large data set allows the variation of their dynamics (angular rotation velocity and meridional circulation) to be studied in detail. Variation both in the dynamics as a function of size and distance to active regions (for feature tracking) and as a function of activity level in the correlation box are studied. These new results allow the possible anchoring depth of these magnetic features to be constrained. The observations of the magnetic network dynamics are not consistent with the dynamics deduced from helioseismology. So, some additional processes must be acting on the magnetic network in order to explain their global dynamics.