Journal : Acta Geophysica
Article : Emergence and evolution of active and ephemeral regions: Comparison between observations and models

Authors :
Lilensten, J.
Laboratoire de Planétologie de Grenoble, OSUG-CNRS, Grenoble, France, jean.lilensten@obs.ujf-grenoble.fr,
Zuccarello, F.
Dipartimento di Fisica e Astronomia, Universitá di Catania, Catania, Italy, fzu@oact.inaf.it,
Abstract : This work aims to describe some aspects relevant to the emergence of magnetic structures on the solar surface. Using high resolution photospheric and chromospheric data, besides than EUV images acquired by space telescopes, the dynamics of rising flux tubes is studied. It is shown that, for both long-lived and short-lived magnetic regions, the flux tubes are initially characterized by a high rising velocity, which eventually decreases as the region develops. Other results concern the timeline of the active regions appearance in the atmospheric layers and the asymmetries in plasma downflows between preceding and following legs of the flux tubes. These results are briefly discussed in the light of most recent models.

Keywords : aktywność słoneczna, solar activity, solar active regions, solar magnetic fields,
Publishing house : Instytut Geofizyki PAN
Publication date : 2009
Number : Vol. 57, no. 1
Page : 15 – 23

Bibliography
: Archontis, V., F. Moreno-Insertis, K. Galsgaard, A. Hood, and E. O'She (2004), Emergence of magnetic flux from the convection zone into the corona, Astron. Astrophys. 426, 1047-1063.
Caligari, P., F. Moreno-Insertis, and M. Schüssler (1995), Emerging flux tubes in the solar convection zone. I: Asymmetry, tilt, and emergence latitude, Astrophys. J. 441, 886-902.
Cauzzi, G., R.C. Canfield, and G.H. Fisher (1996), A search for asymmetric flows in young active regions, Astrophys. J. 456, 850-860.
Elmore, D.F., B.W. Lites, S. Tomczyk, A. Skumanich, R.B. Dunn, J.A. Schuenke, K.V. Streander, T.W. Leach, C.W. Chambellan, Hull, and L.B. Lacey (1992), Advanced Stokes polarimeter: a new instrument for solar magnetic field research, Proc. SPIE Polarization Analysis and Measurement 1746, 22-33.
Guglielmino, S.L., V. Martinez Pillet, B. Ruiz Cobo, F. Zuccarello, and B.W. Lites (2006), A detailed analysis of an ephemeral region, Mem. Soc. Astron. Ital. Suppl. 9, 103-105.
Hagenaar, H.J., C.J. Schrijver, and A.M. Title (2003), The properties of small magnetic regions on the solar surface and the implications for the solar dynamo(s), Astrophys. J. 584, 1107-1119.
Harvey, K.L., and S.F. Martin (1973), Ephemeral Active Regions, Solar Phys. 32, 389-402.
Harvey, K.L., and C. Zwaan (1993), Properties and emergence of bipolar active regions, Solar Phys. 148, 85-118.
Moreno-Insertis, F. (1997), Emergence of magnetic flux from the solar interior, Mem. Soc. Astron. Ital. 68, 429-447.
Nordlund, A., A. Brandenburg, R.L. Jennings, M. Rieutord, J. Ruokolainen, R.F.Stein, and I. Tuominen (1992), Dynamo action in stratified convection with overshoot, Astrophys. J. 392, 647-652.
Schrijver, C.J., A.M. Title, A.A. van Ballegooijen, and R.A. Shine (1997), Sustaining the quiet photospheric network: The balance of flux emergence, fragmentation, merging, and cancellation, Astrophys. J. 487, 424-436.
Spadaro, D., S. Billotta, L. Contarino, P. Romano, and F. Zuccarello (2004), AFS dynamic evolution during the emergence of an active region, Astron. Astrophys. 425, 309-319.
van Driel-Gesztelyi, L. (2002), Emergence and loss of magnetic flux on the solar surface, “ESA SP-505: SOL-MAG 2002”, Proc. Magnetic Coupling of the Solar Atmosphere Euroconference, 113-120.
van Driel-Gesztelyi, L., and K. Petrovay (1990), Asymmetric flux loops in active regions, Solar Phys. 126, 285-298.
Zuccarello, F., V. Battiato, L. Contarino, P. Romano, D. Spadaro, and L. Vlahos (2005), AFS dynamics in a short-lived active region, Astron. Astrophys. 442, 661-671.
Zwaan, C. (1985), The emergence of magnetic flux, Solar Phys. 100, 1-2, 397-414,
DOI :
Qute : Lilensten, J. ,Zuccarello, F. ,Zuccarello, F. , Emergence and evolution of active and ephemeral regions: Comparison between observations and models. Acta Geophysica Vol. 57, no. 1/2009
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