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.

Asymptotic Methods in the Theory of Non-linear Convection

1971 ◽  
Vol 2 (1) ◽  
pp. 45-46
Author(s):  
R. Van Der Borght
Keyword(s):  
Rayleigh Number ◽  
Numerical Integration ◽  
Convection Zone ◽  
Asymptotic Methods ◽  
Basic System ◽  
System Of Differential Equations ◽  
Solar Convection Zone ◽  
Solar Convection ◽  
A Value ◽  
Made In

The effective Rayleigh number, in the solar convection zone, soon reaches a value of the order of 106 and, although considerable progress has been made in the numerical integration of the basic system of differential equations at high Rayleigh number, it is of interest to investigate more fully the application of asymptotic methods to such a problem.

scholarly journals Simulating the Solar Dynamo

1993 ◽  
Vol 157 ◽  
pp. 111-121
Author(s):  
Axel Brandenburg
Keyword(s):  
Eddy Viscosity ◽  
Convection Zone ◽  
Transport Coefficients ◽  
Mean Field ◽  
Field Orientation ◽  
Solar Convection Zone ◽  
Solar Convection ◽  
Magnetic Diffusivity ◽  
The Magnetic Field

Mean-field and direct simulations of the hydrodynamics and hydromagnetics of the solar convection zone are discussed with the ultimate aim to understand the generation of differential rotation and magnetic fields. Various arguments constraining the values of the various turbulent diffusion coefficients are presented. It is suggested that the turbulent magnetic diffusivity is much smaller than the eddy viscosity which, in turn, is by up to a factor of ten smaller than the eddy conductivity. The magnetic field obtained from direct simulations is highly intermittent, and there is no clear systematic orientation of bipolar regions emerging from the convection zone. Various mechanisms that might cause such a field orientation are considered. Finally, the application of direct simulations to the determination of mean-field transport coefficients is emphasised.

The Effect of Rotation on Thermal Convection

1972 ◽  
Vol 2 (2) ◽  
pp. 92-93 ◽  
Author(s):  
J. O. Murphy ◽  
R. Van Der Borght
Keyword(s):  
Rayleigh Number ◽  
Heat Transport ◽  
Cell Size ◽  
Thermal Convection ◽  
Convection Zone ◽  
Total Heat ◽  
The Sun ◽  
Maximum Heat ◽  
Solar Convection Zone ◽  
Solar Convection

An investigation into the influence of rotation on thermal convection has some applicability in the study of the solar convection zone. Of particular interest is the effect of rotation on the total heat transport and the cell size for maximum heat transport at high Rayleigh number, which is estimated to be as high as 1020 for the Sun.

Non-linear Convection with Free Boundaries at High Rayleigh Number

1971 ◽  
Vol 2 (1) ◽  
pp. 51-52 ◽  
Author(s):  
J. O. Murphy
Keyword(s):  
Rayleigh Number ◽  
Temperature Fluctuation ◽  
Convection Zone ◽  
Incompressible Fluids ◽  
Free Boundaries ◽  
Solar Convection Zone ◽  
Solar Convection ◽  
Non Linear ◽  
Convection Problem

It has been suggested, for example by Wilson and Spiegel, that the results from the study of convection in incompressible fluids may provide a basis for the study of the solar convection zone. In fact Wilson’s models contain temperature fluctuation maxima, a feature exhibited by the results obtained from the convection problem for large values of the Rayleigh number.

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.

Sign in / Sign up

Export Citation Format

Share Document