# Azimuthally unidirectional transport of energy in magnetoelectric fields. Topological Lenz effect

## TL;DR

This paper demonstrates a topological Lenz effect where azimuthally unidirectional energy transport in magnetoelectric fields of a ferrite disk induces opposite topological reactions on nearby metal, conserving angular momentum.

## Contribution

It introduces the concept of a topological Lenz effect, showing how topological properties of electromagnetic fields lead to energy transport and reactive responses in ferrite-metal systems.

## Key findings

- Unidirectional energy transport in MDM resonance induces opposite reactions on metal.
- Topological properties ensure angular momentum conservation.
- Magnetoelectric fields induce helical surface currents and charges.

## Abstract

Magnetic dipolar modes (MDMs) in a quasi 2D ferrite disk are microwave energy eigenstate oscillations with topologically distinct structures of rotating fields and unidirectional power flow circulations. At the first glance, this might seem to violate the law of conservation of an angular momentum, since the microwave structure with an embedded ferrite sample is mechanically fixed. However, an angular momentum is seen to be conserved if topological properties of electromagnetic fields in the entire microwave structure are taken into account. In this paper we show that due to the topological action of the azimuthally unidirectional transport of energy in a MDM resonance ferrite sample there exists the opposite topological reaction on a metal screen placed near this sample. We call this effect topological Lenz effect. The topological Lenz law is applied to opposite topological charges, one in a ferrite sample and another on a metal screen. The MDM originated near fields, the magnetoelectric (ME) fields, induce helical surface electric currents and effective charges on a metal. The fields formed by these currents and charges will oppose their cause.

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Source: https://tomesphere.com/paper/1701.05185