# The solar fast dynamo action extended to A, Ap and Am type stars

## TL;DR

This paper proposes an extended fast dynamo mechanism explaining magnetic field generation in the Sun and A, Ap, Am stars through charge separation and Torus structures, linking stellar rotation and plasma properties to magnetic activity cycles.

## Contribution

It introduces a novel dynamo model involving charge separation and Torus structures, extending the fast dynamo concept to A, Ap, and Am stars.

## Key findings

- Magnetic fields in these stars are due to large-scale charge separation.
- Torus structures determine the stellar activity cycle durations.
- Differential rotation and plasma speed are key to magnetic field generation.

## Abstract

Initially, we present our original fast dynamo mechanism being potentially at work concerning the Sun and the solar type stars. Then, based on this new prototype model, a dynamo action model explaining the generation of the magnetic fields for A, Ap and Am type stars will be derived. We argue that their magnetic behavior is essentially due to locally exotic plasma properties leading to large scale charge separation in their interior. Their powerful magnetic fields are generated by the revolution speed of these excess positive or negative charges tightly associated with the formation of one or two so called Torus structures. The lifespan of the Torus charge defines the stellar activity cycle. In the solar case, two Torus structures are formed preserving their charge for 11 years. The Torus charging results from two processes: First, the stellar differential rotation with its shear layers and second, the local plasma property that the plasma rotational speed (U) is equal or greater than the local light speed (v) in the medium. If U is greater than v, then two nearby pocket charges (initially formed by the stellar differential rotation) will be mutually attracted. That is, the attractive magnetic force will be greater than the repulsive electric one. In addition, the same poloidal field, in the subphotosphere shear layer, produces an excess charge generating the starspot activity. The solar birthplace of Torus, within the tachocline, is positioned at 45 deg. latitudes. Each Torus drifts equatorward increasing steadily its own rotational speed and, consequently, its own strength of poloidal magnetic field. A single Torus, over the equatorial plane, is probably formed in the interior of an Ap type star producing its strong and global dipole like magnetic field.

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Source: https://tomesphere.com/paper/1903.08521