Abstract
The emergence of photospheric magnetic fields and the dynamics of the associated pattern of vertical motions in a developing active region are studied based on SOHO/MDI data. Objects were selected for which complete time series of data were available, so as to make it possible to determine the onset time of the magnetic-field emergence at the surface and tracing the formation of the first pores. The active regions studied originated near the central meridian. The total area of sunspots in these regions exceeded 100 millionths of the hemisphere at the maximum of active region evolution. A generalized evolutionary scenario is constructed for the magnetic field and vertical motions in the emerging active region. An asymmetry in the Doppler velocities is noted at an early stage of the active-region development, which corresponds to a matter flow from the leading to the trailing end of the emerging Ω-shaped tube. A direct relationship is found between the matter-downflow velocity in the area of the pore development and the growth in the strength of the longitudinal magnetic field.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Y. Fan, G. H. Fisher, and E. E. DeLuca, Astrophys. J. 405, 390 (1993).
Y. Fan, G. H. Fisher, and A. N. McClymont, Astrophys. J. 436, 907 (1994).
M. Schussler, P. Caligari, A. Ferriz-Mas, and F. Moreno-Insertis, Astron. Astrophys. 281, 69 (1994).
P. Caligari, F. Moreno-Insertis, and M. Schussler, Astrophys. J. 441, 886 (1995).
P. Caligari, M. Schussler, and F. Moreno-Insertis, Astrophys. J. 502, 481 (1998).
Y. Fan and D. Gong, Solar Phys. 192, 141 (2000).
F. Moreno-Insertis, in Sunspots: Theory and Observations, Ed. by J. H. Thomas and N. O. Weiss, NATO Sci. Ser. C 375, 385 (1992).
W. P. Abbett, G. H. Fisher, and Y. Fan, Astrophys. J. 540, 548 (2000).
V. M. Grigor’ev, L. V. Ermakova, and A. I. Khlystova, Pis’ma Astron. Zh. 33, 858 (2007) [Astron. Lett. 33, 766 (2007)].
A. G. Kosovichev, Space Sci. Rev. 144, 175 (2009).
V. M. Grigor’ev, L. V. Ermakova, and A. I. Khlystova, Astron. Zh. 86, 935 (2009) [Astron. Rep. 53, 869 (2009)].
J. J. Brants, Solar Phys. 95, 15 (1985).
S. L. Keil, K. S. Bolasubramaniam, L. A. Smaldone, et al., Astrophys. J. 510, 422 (1999).
B. W. Lites, A. Skumanich, and V. Martinez Pillet, Astron. Astrophys. 333, 1053 (1998).
M. Kubo, T. Shimizu, and B. W. Lites, Astrophys. J. 595, 465 (2003).
G. Cauzzi, R. C. Canfield, and G. H. Fisher, Astrophys. J. 456, 850 (1996).
M. Sigwarth, W. Schmidt, and M. Schuessler, Astron. Astrophys. 33, 53 (1998).
A. A. Pevtsov and J. B. Lamb, in Solar MHD Theory and Observations: A High Spatial Resolution Perspective, Ed. by J. Leibacher, R. F. Stein, and H. Uitenbroek, ASP Conf. Ser. 354, 249 (2006).
S. I. Gopasyuk, Izv. Krymsk. Astrofiz. Observ. 36, 56 (1967).
C. Zwaan, Solar Phys. 60, 213 (1978).
C. Zwaan, Solar Phys. 100, 397 (1985).
E. N. Parker, Astrophys. J. 221, 368 (1978).
Author information
Authors and Affiliations
Additional information
Original Russian Text © V.M. Grigor’ev, L.V. Ermakova, A.I. Khlystova, 2011, published in Astronomicheskii Zhurnal, 2011, Vol. 88, No. 2, pp. 184–195.
Rights and permissions
About this article
Cite this article
Grigor’ev, V.M., Ermakova, L.V. & Khlystova, A.I. The dynamics of photospheric line-of-sight velocities in emerging active regions. Astron. Rep. 55, 163–173 (2011). https://doi.org/10.1134/S1063772911020041
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S1063772911020041