Sign of helicity in the $\alpha$-$\Omega$ geodynamo

TL;DR

This paper investigates the sign of helicity in the Earth's geodynamo, proposing a wave-$mbda$ model where helicity arises from helical waves, offering new insights into geomagnetic phenomena like westward drift and reversals.

Contribution

It introduces a wave-$mbda$ model for the geodynamo where helicity is generated by helical waves, differing from traditional flow-based models.

Findings

Proposes a wave-$mbda$ model for the geodynamo.

Provides a tentative interpretation of geomagnetic phenomena.

Highlights the role of helical waves in helicity sign in the geodynamo.

Abstract

In this paper we discuss the sign of helicity in the $\alpha$-$\Omega$ dynamo and propose a wave-$\Omega$ model in which the $\alpha$ effect in the geodynamo is induced by helical wave but not helical flow as in the solar dynamo. We then tentatively interpret the mechanisms of the Earth's magnetic westward drift, tilt angle, and dipole reversals.