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HINODE Operation Plan (HOP)

accepted on


 HOP No.

 HOP title

HOP 0115

Study of the photosphere dynamic at different heliographic latitudes by computing kinetic energy spectra of the horizontal velocity field

plan term


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 name : Roudier,Rieutord @  e-mail : Observatoire Midi Pyrénées, UMR5572 ,57 Av. dfAzeirex, BP 826 6500 Tarbes cedex, France

contact person in HINODE team

 name : Berger @  e-mail : berger[at]lmsal.com

 abstract of observational proposal
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.

 request to SOT
SOT/BFI:@images in the Blue continuum: ideal time step: 30s ,  pixel = 0.1 arcsec

However, if telemetry needs it or if longer time sequence are thus doable, the time step may be increased up to 60s.

Different latitudes are required along the central meridian, namely 15‹, 30‹, 45‹, 60‹, 75‹.
If the observations can be done before june 2009, we choose south direction, and after june 2009 the north direction,  for the latitudinal scan.

We also plan to observe at the same time (3 to 6 hours) from Pic du Midi over a large field of view (10fx10f) in  the G-band with our 4kx4k CMOS camera CALAS (http://ljr.bagn.obs-mip.fr/calas/index.html).

 request to XRT

 request to EIS

 other participating instruments
PiC du Midi


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