scholarly journals Asymptotic properties of low degree gravity modes

1988 ◽  
Vol 123 ◽  
pp. 121-124
Author(s):  
Gabrielle Berthomieu ◽  
Janine Provost
Keyword(s):  
Convection Zone ◽  
Asymptotic Properties ◽  
Global Constraints ◽  
Type Model ◽  
Solar Model ◽  
Solar Convection Zone ◽  
Solar Convection ◽  
Deep Interior ◽  
Low Degree ◽  
Solar Type

Asymptotic properties of low degree gravity modes and their relation to the stratification of the model through the Brunt-Väissälä frequency are discussed for a solar type model and for a 10 M⊙ model. For the solar model, taking into account the quasiadiabaticity of the solar convection zone, it is shown that two global constraints on the deep interior of the solar model can be derived from a set of g-modes periods in the observed range. However modes with large periods, i.e. larger than those up to now observed, are required to obtain informations on the stratification just below the convection zone. For the 10 M⊙ model, the preliminary results show that the existence of a layer with a large mean molecular weight gradient destroys the equidistance of the periods of gravity modes of a given degree and that some informations on the properties of this layer can be obtained from the analysis of the g-modes periods.

scholarly journals Can short time delays influence the variability of the solar cycle?

2010 ◽  
Vol 6 (S271) ◽  
pp. 288-296
Author(s):  
Laurène Jouve ◽  
Michael R. E. Proctor ◽  
Geoffroy Lesur
Keyword(s):  
Solar Cycle ◽  
Convection Zone ◽  
Mean Field ◽  
Period Doubling ◽  
Temporal Modulation ◽  
Solar Convection Zone ◽  
Flux Tubes ◽  
Solar Convection ◽  
Short Time ◽  
Period Doubling Bifurcations

AbstractWe present the effects of introducing results of 3D MHD simulations of buoyant magnetic fields in the solar convection zone in 2D mean-field Babcock-Leighton models. In particular, we take into account the time delay introduced by the rise time of the toroidal structures from the base of the convection zone to the solar surface. We find that the delays produce large temporal modulation of the cycle amplitude even when strong and thus rapidly rising flux tubes are considered. The study of a reduced model reveals that aperiodic modulations of the solar cycle appear after a sequence of period doubling bifurcations typical of non-linear systems. We also discuss the memory of such systems and the conclusions which may be drawn concerning the actual solar cycle variability.

Depth Dependence of Physical Parameters Associated with Convection in the Solar Atmosphere

1971 ◽  
Vol 2 (1) ◽  
pp. 50-51
Author(s):  
B. E. Waters
Keyword(s):  
Steady State ◽  
Rayleigh Number ◽  
Eddy Viscosity ◽  
Convection Zone ◽  
Finite Amplitude ◽  
Physical Parameters ◽  
Solar Granulation ◽  
Solar Convection Zone ◽  
Solar Convection ◽  
Convective Phenomenon

It has been often suggested that the solar granulation is essentially a turbulent convective phenomenon. It is then worthwhile to investigate steady state, finite-amplitude convection in the outer layers of the solar convection zone. On the basis that the convection zone is turbulent, we will define an eddy viscosity; and for the present we will consider only the first 300 km of the convection zone. This value is predicted by van der Borght using an asymptotic analysis of convection at high Rayleigh number—provided we assume the horizontal dimension of the cellular pattern to be ˜1000 km.

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