Numerical Simulations of Ionospheric Dynamo Model in a Non-uniform Magnetic Field

Magnetic Fields in the Spiral Galaxy NGC 6946

Symposium - International Astronomical Union ◽

10.1017/s0074180900174327 ◽

1993 ◽

Vol 157 ◽

pp. 311-312

Author(s):

Matthias Ehle ◽

Rainer Beck

Keyword(s):

Magnetic Field ◽

Spiral Galaxy ◽

High Frequency ◽

Uniform Magnetic Field ◽

Large Scale ◽

Dynamo Model ◽

Model Parameters ◽

Radio Waves ◽

Spiral Pattern ◽

Ngc 6946

High frequency polarization observations reveal the existence of a large-scale ordered magnetic field in the disk of the spiral galaxy NGC 6946. At lower frequencies the disk is no longer transparent to polarized radio waves due to Faraday depolarization. The spiral pattern of the uniform magnetic field and the distribution of polarized intensities are fairly well simulated by a dynamo model. The model parameters indicate that the dynamo does not only operate in the disk, but also in the halo.

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Numerical simulations of the ionospheric striation model in a non-uniform magnetic field

Computer Physics Communications ◽

10.1016/j.cpc.2006.07.022 ◽

2007 ◽

Vol 176 (2) ◽

pp. 75-90 ◽

Cited By ~ 4

Author(s):

Christophe Besse ◽

Jean Claudel ◽

Pierre Degond ◽

Fabrice Deluzet ◽

Gérard Gallice ◽

...

Keyword(s):

Magnetic Field ◽

Numerical Simulations ◽

Uniform Magnetic Field

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

International Astronomical Union Colloquium ◽

10.1017/s0252921100064861 ◽

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.

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