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Astron. Astrophys. 319, 683-693 (1997)

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Cycle 19 facula dynamics

II. Meridional circulation, rms velocity, and Reynolds stresses

N. Meunier 1, E. Nesme-Ribes 1 and B. Collin 2

1 URA 2080 CNRS, Département d'Astronomie Solaire et Planétaire, Observatoire de Paris, 5 Place Janssen, F-92195 Meudon, France
2 CREA/SP, Etablissement Technique Central de l'Armement, F-94114 Arcueil, France

Received 20 May 1996 / Accepted 14 August 1996


We investigated the meridional circulation of photospheric faculae throughout cycle 19. Together with the rotation observed in a companion paper (Meunier et al. 1996), we were able to address the problem of the existence of the observed differential rotation. The meridional circulation is characterized by a strong north-south asymmetry. The distribution of meridional circulation around the mean value confirms the existence of two populations detected in Meunier et al. (1996). An investigation of the rms velocities yields information on the variation of the anisotropy between the two horizontal motions and the latitudinal dependence of the small-scale kinetic energy. Lastly, a very small facula covariance has been measured, and its variation during the cycle has been established.

Key words: Sun: faculae – Sun: magnetic fields – Sun: rotation – sunspots – Turbulence

Send offprint requests to: N. Meunier


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© European Southern Observatory (ESO) 1997

Online publication: July 3, 1998