On a Babcock-Leighton dynamo model with a deep-seated generating layer for the toroidal magnetic field

Solar Physics ◽  
1995 ◽  
Vol 160 (2) ◽  
pp. 213-235 ◽  
Author(s):  
Bernard R. Durney
Keyword(s):  
Magnetic Field ◽  
Toroidal Magnetic Field ◽  
Dynamo Model

scholarly journals On the extended 23rd solar cycle

2012 ◽  
Vol 8 (S294) ◽  
pp. 69-70 ◽  
Author(s):  
Valery N. Krivodubskij
Keyword(s):  
Magnetic Field ◽  
Solar Cycle ◽  
Toroidal Field ◽  
Toroidal Magnetic Field ◽  
Dynamo Model ◽  
Linear Regime ◽  
23Rd Solar Cycle ◽  
23Rd Cycle ◽  
Inverse Proportion ◽  
Non Linear

AbstractAn explanation of the mystery of the extended 23rd solar cycle duration about 13 years in the frame of non-linear regime of the αΩ- dynamo model is proposed. The calculated dynamo-period of the solar cycle, T, depends (in the inverse proportion) on the intensity of the α- effect in the solar convection zone (SCZ). As well, the intensity of the α- effect in non-linear regime depends (also in the inverse proportion) on the value of toroidal magnetic field, BT (magnetic alpha-quenching). Thus, the calculated period is in direct proportion to the value of toroidal magnetic field: the stronger toroidal field BT in certain cycle, the longer dynamo-period T of this cycle. Since the toroidal field is hidden in the deep layers of the SCZ, it is necessary to know some other magnetic experimental evidence that reflects something like information about inner toroidal field. In this connection we allow for that the strong toroidal field is transported by magnetic buoyancy to the solar surface and produces here the sunspots, so they carry indirect information on BT. In this connection we took into account up-to-date observed data on the essential increase of the averaged annual module of the magnetic field of the large-scale sunspots, Bsp, in the 23rd cycle; and then we made calculation of the alpha-quenching which depends on these referred data. It is important to know only relative variations of magnetic index Bsp for calculation of the dynamo-period variation. Our estimations showed that the average solar period, which is about 11 years, must increase by a factor of 1,2; so the calculated 23rd cycle dynamo-period would be about 13 years.

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 An 84-μG Magnetic Field in a Galaxy at Z=0.692?

2008 ◽  
Vol 4 (S254) ◽  
pp. 95-96
Author(s):  
Arthur M. Wolfe ◽  
Regina A. Jorgenson ◽  
Timothy Robishaw ◽  
Carl Heiles ◽  
Jason X. Prochaska
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Faraday Rotation ◽  
Large Scale ◽  
Dynamo Model ◽  
Magnetic Field Generation ◽  
Interstellar Gas ◽  
Splitting Technique ◽  
Average Value ◽  
The Magnetic Field

AbstractThe magnetic field pervading our Galaxy is a crucial constituent of the interstellar medium: it mediates the dynamics of interstellar clouds, the energy density of cosmic rays, and the formation of stars (Beck 2005). The field associated with ionized interstellar gas has been determined through observations of pulsars in our Galaxy. Radio-frequency measurements of pulse dispersion and the rotation of the plane of linear polarization, i.e., Faraday rotation, yield an average value B ≈ 3 μG (Han et al. 2006). The possible detection of Faraday rotation of linearly polarized photons emitted by high-redshift quasars (Kronberg et al. 2008) suggests similar magnetic fields are present in foreground galaxies with redshifts z > 1. As Faraday rotation alone, however, determines neither the magnitude nor the redshift of the magnetic field, the strength of galactic magnetic fields at redshifts z > 0 remains uncertain.Here we report a measurement of a magnetic field of B ≈ 84 μG in a galaxy at z =0.692, using the same Zeeman-splitting technique that revealed an average value of B = 6 μG in the neutral interstellar gas of our Galaxy (Heiles et al. 2004). This is unexpected, as the leading theory of magnetic field generation, the mean-field dynamo model, predicts large-scale magnetic fields to be weaker in the past, rather than stronger (Parker 1970).The full text of this paper was published in Nature (Wolfe et al. 2008).

scholarly journals The magnetic helicity density patterns from non-axisymmetric solar dynamo

2021 ◽  
Vol 87 (1) ◽  
Author(s):  
Valery V. Pipin
Keyword(s):  
Magnetic Field ◽  
Differential Rotation ◽  
Conservation Law ◽  
Large Scale ◽  
Solar Dynamo ◽  
Magnetic Helicity ◽  
Dynamo Model ◽  
Density Distributions ◽  
Large Scale Magnetic Field ◽  
Helicity Conservation

We study the helicity density patterns which can result from the emerging bipolar regions. Using the relevant dynamo model and the magnetic helicity conservation law we find that the helicity density patterns around the bipolar regions depend on the configuration of the ambient large-scale magnetic field, and in general they show a quadrupole distribution. The position of this pattern relative to the equator can depend on the tilt of the bipolar region. We compute the time–latitude diagrams of the helicity density evolution. The longitudinally averaged effect of the bipolar regions shows two bands of sign for the density distributions in each hemisphere. Similar helicity density patterns are provided by the helicity density flux from the emerging bipolar regions subjected to surface differential rotation.

Features of the Radial and Axial Distributions of the Toroidal Magnetic Field in the Axial Jet Ejection at the PF-3 Facility

2021 ◽  
Vol 47 (9) ◽  
pp. 912-937
Author(s):  
V. I. Krauz ◽  
K. N. Mitrofanov ◽  
V. V. Myalton ◽  
I. V. Il’ichev ◽  
A. M. Kharrasov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Toroidal Magnetic Field
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