scholarly journals Sunspot seismology

1988 ◽  
Vol 123 ◽  
pp. 181-182
Author(s):  
John H. Thomas ◽  
Bruce W. Lites ◽  
Toufik E. Abdelatif
Keyword(s):  
Theoretical Analysis ◽  
Observational Study ◽  
Convection Zone ◽  
The Sun ◽  
Full Account ◽  
Sunspot Umbra

The 5 minute oscillations in a sunspot umbra are the response of the sunspot to forcing by the 5 minute p-modes in the surrounding convection zone (Thomas 1981). This interaction of solar p-modes with a sunspot can be used to probe the structure of a sunspot beneath the visible surface of the Sun (Thomas, Cram, and Nye 1982). Here we report briefly the results of both an observational study and a simple theoretical analysis of this interaction. A full account of these results will be published elsewhere (Abdelatif, Lites, and Thomas 1986; Abdelatif and Thomas 1987).

scholarly journals Magnetoconvection Patterns in Rotating Convection Zones

1991 ◽  
Vol 130 ◽  
pp. 37-56
Author(s):  
Paul H. Roberts
Keyword(s):  
Convection Zone ◽  
Solar Surface ◽  
Giant Cells ◽  
Conclusive Evidence ◽  
The Other ◽  
The Sun ◽  
Solar Convection Zone ◽  
Solar Convection ◽  
Entire Thickness ◽  
Convective Motions

AbstractIn addition to the well-known granulation and supergranulation of the solar convection zone (the “SCZ”), the presence of so-called “giant cells” has been postulated. These are supposed span the entire thickness of the SCZ and to stretch from pole to pole in a sequence of elongated cells like a “cartridge belt” or a bunch of “bananas” strung uniformly round the Sun. Conclusive evidence for the existence of such giant cells is still lacking, despite strenuous observational efforts to find them. After analyses of sunspot motion, Ribes and others believe that convective motions near the solar surface occurs in a pattern that is the antithesis of the cartridge belt: a system of “toroidal” or “doughnut” cells, girdling the Sun in a sequence that extends from one pole to the other. Galloway, Jones and Roberts have recently tried to meet the resulting theoretical challenge, with the mixed success reported in this paper.

scholarly journals The Toroidal Magnetic Field inside the Sun

1991 ◽  
Vol 130 ◽  
pp. 187-189
Author(s):  
V.N. Krivodubskij ◽  
A.E. Dudorov ◽  
A.A. Ruzmaikin ◽  
T.V. Ruzmaikina
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Convection Zone ◽  
The Sun ◽  
Poloidal Magnetic Field ◽  
Radial Gradient ◽  
The Core ◽  
Large Scale Magnetic Field ◽  
Magnetic Buoyancy ◽  
The Magnetic Field

Analysis of the fine structure of the solar oscillations has enabled us to determine the internal rotation of the Sun and to estimate the magnitude of the large-scale magnetic field inside the Sun. According to the data of Duvall et al. (1984), the core of the Sun rotates about twice as fast as the solar surface. Recently Dziembowski et al. (1989) have showed that there is a sharp radial gradient in the Sun’s rotation at the base of the convection zone, near the boundary with the radiative interior. It seems to us that the sharp radial gradients of the angular velocity near the core of the Sun and at the base of the convection zone, acting on the relict poloidal magnetic field Br, must excite an intense toroidal field Bф, that can compensate for the loss of the magnetic field due to magnetic buoyancy.

Convection and the solar abundances: Does the sun have a sub-solar metallicity?

2006 ◽  
Vol 2 (S239) ◽  
pp. 122-129
Author(s):  
Martin Asplund
Keyword(s):  
Convection Zone ◽  
Model Atmosphere ◽  
Solar Photosphere ◽  
The Sun ◽  
Line Formation ◽  
Solar Convection ◽  
Solar Metallicity ◽  
Solar Abundances ◽  
Hydrodynamical Simulations ◽  
Mixing Length Theory

AbstractIn the Sun, the convection zone reaches up to the solar photosphere and can thus directly influence the emergent spectrum. Traditionally, the effects of convection has been modelled with the local mixing length theory in theoretical 1D hydrostatic model atmospheres. In a different approach, we have performed realistic time-dependent, 3D, radiative-hydrodynamical simulations of the outer layers of the solar convection zone, including the photosphere. Both the different mean stratification and the presence of atmospheric inhomogeneities in 3D impact the spectral line formation. In a series of papers, we have applied our 3D solar model atmosphere to the problem of the solar chemical composition. Furthermore, we have adopted the best possible atomic and molecular line data and taken into account departures from LTE in the line formation when necessary. The inferred C, N, O and Ne abundances are all significantly lower than estimated from previous 1D modelling by 0.2-0.3 dex. These results have significant implications for a range of topics in contemporary astrophysics, including causing a severe headache for helioseismology.

scholarly journals On the Kline Width-Absolute Magnitude Relation

1973 ◽  
Vol 54 ◽  
pp. 64-67
Author(s):  
M. K. V. Bappu
Keyword(s):  
Line Width ◽  
Solar Disk ◽  
Convection Zone ◽  
Absolute Magnitude ◽  
Stellar Atmosphere ◽  
The Sun

Bright fine mottles seen on the solar disk are identified as the agency that locates the Sun on the K-line width-absolute magnitude relation of Wilson and Bappu. The contribution of the supergranular network emission and the plage emission from centres of activity tends to upset the uniqueness of the relation. The line width-absolute magnitude relation is thus a characteristic of the convection zone underlying the stellar atmosphere.

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