Solar Internal Rotation and Dynamo Waves: A Two-Dimensional Asymptotic Solution in the Convection Zone

2000 ◽  
Vol 179 ◽  
pp. 379-380
Author(s):  
Gaetano Belvedere ◽  
Kirill Kuzanyan ◽  
Dmitry Sokoloff
Keyword(s):  
Magnetic Field ◽  
Asymptotic Solution ◽  
Internal Rotation ◽  
Convection Zone ◽  
General Idea ◽  
Dynamo Model ◽  
Axially Symmetric ◽  
Dynamo Action ◽  
Regeneration Rate ◽  
Dynamo Waves

Extended abstractHere we outline how asymptotic models may contribute to the investigation of mean field dynamos applied to the solar convective zone. We calculate here a spatial 2-D structure of the mean magnetic field, adopting real profiles of the solar internal rotation (the Ω-effect) and an extended prescription of the turbulent α-effect. In our model assumptions we do not prescribe any meridional flow that might seriously affect the resulting generated magnetic fields. We do not assume apriori any region or layer as a preferred site for the dynamo action (such as the overshoot zone), but the location of the α- and Ω-effects results in the propagation of dynamo waves deep in the convection zone. We consider an axially symmetric magnetic field dynamo model in a differentially rotating spherical shell. The main assumption, when using asymptotic WKB methods, is that the absolute value of the dynamo number (regeneration rate) |D| is large, i.e., the spatial scale of the solution is small. Following the general idea of an asymptotic solution for dynamo waves (e.g., Kuzanyan & Sokoloff 1995), we search for a solution in the form of a power series with respect to the small parameter |D|–1/3(short wavelength scale). This solution is of the order of magnitude of exp(i|D|1/3S), where S is a scalar function of position.

scholarly journals Anharmonic and standing dynamo waves: theory and observation of stellar magnetic activity

2006 ◽  
Vol 365 (1) ◽  
pp. 181-190 ◽  
Author(s):  
S. Baliunas ◽  
P. Frick ◽  
D. Moss ◽  
E. Popova ◽  
D. Sokoloff ◽  
...  
Keyword(s):  
Magnetic Activity ◽  
Dynamo Waves ◽  
Stellar Magnetic Activity

Asymptotic properties of dynamo waves

2008 ◽  
pp. 213-217 ◽  
Author(s):  
D. Sokoloff ◽  
E. Nesme-Ribes ◽  
M. Fioc
Keyword(s):  
Asymptotic Properties ◽  
Dynamo Waves

Long dynamo waves

2005 ◽  
Vol 205 (1-4) ◽  
pp. 100-124 ◽  
Author(s):  
Joanne Mason ◽  
Edgar Knobloch
Keyword(s):  
Dynamo Waves

scholarly journals Dynamo waves and palaeomagnetic secular variation

1987 ◽  
Vol 88 (1) ◽  
pp. 139-159 ◽  
Author(s):  
P. Olson ◽  
V. L. Hagee
Keyword(s):  
Secular Variation ◽  
Dynamo Waves

Periodicity and aperiodicity in solar magnetic activity

1990 ◽  
Vol 330 (1615) ◽  
pp. 617-625 ◽  
Keyword(s):  
Magnetic Activity ◽  
Convective Zone ◽  
Magnetic Cycle ◽  
The Past ◽  
Proxy Records ◽  
Solar Magnetic Activity ◽  
Hydromagnetic Dynamo ◽  
Dynamo Waves ◽  
Plausible Theory ◽  
Sunspot Record

Solar activity varies irregularly with an 11-year period whereas the magnetic cycle has a period of 22 years. Similar cycles of activity are seen in other slowly rotating late-type stars. The only plausible theory for their origin ascribes them to a hydromagnetic dynamo operating at, or just below, the base of the convective zone. Linear (kinematic) dynamo models yield strictly periodic solutions with dynamo waves propagating towards or away from the equator. Nonlinear (magnetohydrodynamic) dynamo models allow transitions from periodic to quasi-periodic to chaotic behaviour, as well as loss of spatial symmetry followed by the development of complex spatial structure. Results from simple models can be compared with the observed sunspot record over the past 380 years and with proxy records extending over 9000 years, which show aperiodic modulation of the 11-year cycle.

Meridional circulation and dynamo waves

2008 ◽  
Vol 329 (7) ◽  
pp. 766-768 ◽  
Author(s):  
H. Popova ◽  
D. Sokoloff
Keyword(s):  
Meridional Circulation ◽  
Dynamo Waves

scholarly journals Waves of Solar Activity

1991 ◽  
Vol 130 ◽  
pp. 117-128
Author(s):  
M.R.E. Proctor ◽  
E.A. Spiegel
Keyword(s):  
Solar Activity ◽  
Solitary Wave ◽  
Bifurcation Theory ◽  
Sunspot Cycle ◽  
Approximate Equation ◽  
Periodic Behavior ◽  
Butterfly Diagram ◽  
Dynamo Waves

AbstractWe develop a theory of the sunspot cycle predicated on the assumption that the observed bands of activity are packets of dynamo waves. An approximate equation is proposed to describe the dynamics of these packets, using standard ideas from bifurcation theory. We show that in a certain limit the system can be described in terms of a slowly-evolving solitary wave, and that periodic behavior, like that of the observed butterfly diagram, can easily be found. Generalizations of the theory are discussed.

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