The structure of the solar photospheric convection on granular and mesogranular scales
Heading:
| 1Baran, OA, 1Stodilka, MI 1Astronomical Observatory of Ivan Franko National University of Lviv, Lviv, Ukraine |
| Kinemat. fiz. nebesnyh tel (Online) 2015, 31(2):21-33 |
| Start Page: Solar Physics |
| Language: Ukrainian |
Abstract: We investigated the vertical structure of the photospheric convection of the Sun using neutral iron line λ ≈ 639.3 nm profiles taken around the centre of the solar disc in a non-perturbed region. The observations were obtained at the 70-cm German Vacuum Tower Telescope (Canary Islands, Spain) with high spatial resolution. The spatio-temporal variations of kinematic and thermodynamic parameters were reproduced by solving nonequilibrium inverse radiation transfer problem. Acoustic waves were removed by k-ω-filtration. We analyzed spatial variations of temperature, vertical velocity, density and gas pressure within convective cells of granular scales (0.5...5.0 Мm) and of mesogranular scales (5... 12 Мм) at different heights of the solar photosphere (h = 25...500 km). Extending to upper photosphere layers, the convective structure changes similarly at these scales: at the heights h = 200...250 km the temperature inversion takes place; the convective velocity inversion may occur at the same heights; at the heights h = 50...100 km the inversion of relative variations of density is found, the relative variations of density and pressure increase with heights and they become positive within ascending flows and negative in descending flows. |
| Keywords: photospheric convection, Sun, VTT telescope |
References:
1.A. A. Baran and M. I. Stodilka, “Spatial variations of convective motions in the real solar photosphere,” Izv. Crimean Astrophys. Obs. 109(3), 31–39 (2013).
2.O. A. Baran, “Mesogranulation in the solar atmosphere,” Zh. Fiz. Dosl. 16, 3902 (2012).
3.O. A. Baran and M. I. Stodilka, “Specifics of the solar photospheric convection at granulation, mesogranulation, and supergranulation scales,” Kinematics Phys. Celestial Bodies 30, 173–181 (2014).
https://doi.org/10.3103/S0884591314040023
4.R. I. Kostyk and N. G. Schukina, “Fine structure of convective motions in the solar photosphere: observations and theory,” Astron. Zh. 81, 846–859 (2004).
5.M. I. Stodilka, “Thermal structure of the real solar granulation,” Kinematika Fiz. Nebesnykh Tel 19, 407–416 (2003).
6.M. I. Stodilka and O. A. Baran, “Structure of the solar photospheric convection on subgranulation scales,” Kinematics Phys. Celestial Bodies 24, 70–76 (2008).
https://doi.org/10.3103/S0884591308020025
7.M. I. Stodilka, O. A. Baran, and S. Z. Malinich, “Pecularities of the convection in the solar photosphere,” Kinematika Fiz. Nebesnykh Tel 22, 173–182 (2006).
8.M. I. Stodilka, “The inverse task for the study of heterogenities in the atmosphere of sun and star,” Zh. Fiz. Dosl. 6, 435–442 (2002).
9.M. Asplund, H.-G. Ludvig, A. Nordlund, and R. F. Stein, “The effects of numerical resolution on hydrodynamical surface convection simulations and spectral line formation,” Astron. Astrophys. 359, 669–681 (2000).
10.O. A. Baran, “Structure of convective flows of the real Solar granulation,” Adv. Astron. Space Physics: Conf. Proc. 1, 53–56 (2011).
11.O. A. Baran, “Structure of convective flows on supergranular scales in the solar photosphere,” Adv. Astron. Space Physics: Conf. Proc. 2, 153–156 (2012).
12.O. A. Baran, “Power spectra of convective motions in the solar photosphere,” Adv. Astron. Space Physics: Conf. Proc. 3, 89–93 (2013).
13.O. Espagnet, R. Muller, T. Roudier, et al., “Penetration of the solar granulation into the photosphere: height dependence of intensity and velocity fluctuations,” Astron. Astrophys., Suppl. Ser. 109, 79–108 (1995).
14.A. S. Gadun, A. Hanslmeier, K. N. Pikalov, et al., “Size-dependent properties of simulated 2-D solar granulation,” Astron. Astrophys., Suppl. Ser. 146, 267–291 (2000).
https://doi.org/10.1051/aas:2000271
15.J. Hirzberger, J. A. Bonet, M. Vázquez, and A. Hanslmeier, “Time series of solar granulation images. III. Dynamics of exploding granules and related phenomena,” Astrophys. J. 527, 405–414 (1999).
https://doi.org/10.1086/308065
16.R. I. Kostik, “Fine structure of Fraunhofer lines and the structure of the solar atmosphere,” Sov. Astron. 29, 65–71 (1985).
17.R. Kostik, E. Khomenko, “Solar granulation from photosphere to low chromosphere observed in Ba II 4554 — line,” Astron. Astrophys. 506, 1405–1414 (2009).
https://doi.org/10.1051/0004-6361/200912441
18.R. I. Kostyk and N. Shchukina, “Fine structure of convective motions in the solar photosphere: observations and theory,” Astron. Rep. 48, 769–780 (2004).
https://doi.org/10.1134/1.1800177
19.L. Matloch, R. Cameron, D. Schmitt, and M. Schussler, “Modelling of solar mesogranulation,” Astron. Astrophys. 504, 1041–1055 (2009).
https://doi.org/10.1051/0004-6361/200811200
20.J. P. Mehltretter, “Balloon-borne imagery of the solar granulation. II. The lifetime of solar granulation,” Astron. Astrophys. 62, 311–316 (1978).
21.A. Nordlund, R. F. Stein, and M. Asplund, “Solar surface convection,” Living Rev. Sol. Phys. 6(2), 1–117 (2009).
22.L. J. November, J. Toomre, K. B. Gebbie, and G. W. Simon, “The detection of mesogranulation on the sun,” Astrophys. J. 245(2), L123–L126 (1981).
https://doi.org/10.1086/183539
23.S. R. O. Ploner, S. K. Solanki, and A. S. Gadun, “The evolution of solar granules deduced from 2-D simulations,” Astron. Astrophys. 352, 679–696 (1999).
24.W. Potzi, P. N. Brandt, and A. Hanslmeier, “Variation of granular evolution at meso-scales,” Hvar Obs. Bull. 27, 39–46 (2003).
25.K. Puschmann, B. Ruiz Cobo, M. Vazquez, et al., “Time series of high resolution photospheric spectra in a quiet region of the Sun. II. Analysis of the variation of physical quqntities of granular structures,” Astron. Astrophys. 441, 1157–1169 (2005).
https://doi.org/10.1051/0004-6361:20047193
26.M. P. Rast, “On the nature of “exploding” granules and granule fragmentation.” Astrophys. J. 443, 863–868 (1995).
https://doi.org/10.1086/175576
27.M. Rieutord, T. Roudier, J. M. Malherbe, and F. Rincon, “On mesogranulation, network formation and supergranulation,” Astron. Astrophys. 357, 1063–1072 (2000).
28.Th. Roudier, F. Ligniéres, M. Rieutord, et al., “Families of fragmenting granules and their relation to meso- and supergranular flow fields,” Astron. Astrophys. 409, 299–308 (2003).
https://doi.org/10.1051/0004-6361:20030988
30.Th. Roudier and R. Muller, “Relation between families of granules, mesogranules and photospheric network.” Astron. Astrophys. 419, 757–762 (2004).
https://doi.org/10.1051/0004-6361:20035739
31.R. F. Stein, “Solar surface magneto-convection,” Living Rev. Sol. Phys. 9(4), 1–51 (2012).
32.R. F. Stein and A. Nordlund, “Topology of convection beneath the solar surface,” Astrophys. J. 342, L95–L98 (1989).
https://doi.org/10.1086/185493
33.A. M. Title, T. D. Tarbell, K. P. Topka, et al., “Statistical properties of solar granulation derived from the SOUP instrument on Spacelab 2,” Astrophys. J. 336, 475–494 (1989).
https://doi.org/10.1086/167026
34.J. E. Vernazza, E. H. Avrett, and R. Loeser, “Structure of the solar chromosphere. III. Models of the EUV brightness components of the quiet-sun,” Astrophys. J., Suppl. Ser. 45, 635–725 (1981).
https://doi.org/10.1086/190731