Generation of Coronal Currents by the Solar Convection Zone

AbstractSolar flares are thought to be caused by reconnection of magnetic fields and their associated electric currents in the solar corona. The currents have to be there to provide available energy over and above the current-free minimum energy state, but what generates them has been little discussed. This paper investigates the idea that twisting motions in the turbulent convection zone below may provide a natural source for the currents and explain some of their properties. The twists generate upward-propagating Alfvén waves with a Poynting flux of the right order of magnitude to power a flare. Depending on the depth it takes place, the twisting event that initiates a particular flare may occur hours, days or even months before the flare itself.

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A Dynamo Model for Magnetic Stars with Long Periods

International Astronomical Union Colloquium ◽

10.1017/s0252921100080416 ◽

1976 ◽

Vol 32 ◽

pp. 39-42

Author(s):

M. Schüssler

Keyword(s):

Magnetic Field ◽

Main Sequence ◽

Convection Zone ◽

Dynamo Model ◽

Magnetic Stars ◽

Order Of Magnitude ◽

Linear Effects ◽

The Right ◽

Right Order ◽

The Magnetic Field

SummaryA α - effect dynamo model is presented which can be relevant for the group of magnetic stars.with observed periods between 1 y and 72 ys. The model is based on an axisymmetric α2- dynamo including non-linear effects due to the “cut off α- effect”; no differential rotation is taken into account. There are oscilliations of the magnetic field with periods in the right order of magnitude under the assumption of an outer convection zone between R ≥ r ≥.5 R ….7R. In the sense of this model therefore these stars should be young objects passing from their Hayashi track down to the main sequence.

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

Proceedings of the International Astronomical Union ◽

10.1017/s1743921311017716 ◽

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.

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Berechnung der Oberfläche von Kernmaterie mit Hilfe spezieller Einteilchen-Wellenfunktionen

Zeitschrift für Naturforschung A ◽

10.1515/zna-1962-0803 ◽

1962 ◽

Vol 17 (8) ◽

pp. 640-649

Author(s):

Franz Lanzl

Keyword(s):

Surface Energy ◽

Plane Waves ◽

Yukawa Interaction ◽

Range Interaction ◽

Zero Range ◽

Volume Energy ◽

Order Of Magnitude ◽

The Right ◽

Right Order ◽

Surface Thickness

Using a YUKAWA interaction between the nucleons the volume energy per particle and the specific surface energy are calculated. These expressions assume a very simple form for a zero range interaction. The space parts of the applied orthogonal single particle wave functions are products of plane waves and a momentum independent function which brings about the decrease in density within the surface layer. First the volume energy per particle as a function of the density in the interior of nuclear matter is minimized. The interaction parameters are so selected that the values of the volume energy per particle and the density at the minimum agree with the experimental data. Then the surface energy as a function of the surface thickness is minimized. The values of the surface energy and the surface thickness in the minimum are compared with the empirical data. They are found to be of the right order of magnitude

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