Understanding the distribution and diffusion of magnetic flux at the solar surface is of primary importance to describe many aspects of solar magnetism. This requires to uncover the physical nature of the flows at various scales, which contribute to the transport of magnetic elements. Amongst these scales, supergranulation plays a particular role but its physical origin is still in debate: whether supergranules originate from convective processes (Simon and Weiss, 1968) or from a large-scale instability of the turbulent granular flow (Rieutord et al. 2000) is not known. No direct relation has been evidenced so far between the small-scale granulation and supergranulation. Answering these questions requires high-resolution observations of the solar surface dynamics on a large field of view and for several consecutive hours. A long time sequence from HINODE/SOT on 29-30 August 2007, at the disc centre, which fulfils some of these requirements, has allowed us to compute kinetic energy spectra of the horizontal velocity field at the equator (see figure 1 of Rincon, F., Roudier, Th., Rieutord, M. et al. 2008). We would like now to determine the influence of the latitude on the surface dynamics of the Sun during the minimum phase of the solar cycle. That goal requires image time series at different latitudes along the central meridian during at least 3h or more if possible for each position. |
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