The magnetic properties of the hollow cylindrical ideal remanence magnet

TL;DR

This paper analyzes the magnetic properties of an ideal remanence magnet with a hollow cylindrical shape, comparing its efficiency and field strength to a Halbach cylinder of similar size.

Contribution

It derives the remanence distribution for the ideal remanence magnet and compares its magnetic field and efficiency to the Halbach cylinder.

Findings

The ideal remanence magnet generates a lower magnetic field than the Halbach cylinder.

The ideal remanence magnet is more energy-efficient.

The Halbach cylinder produces twice the magnetic field of the ideal remanence magnet.

Abstract

We consider the magnetic properties of the hollow cylindrical ideal remanence magnet. This magnet is the cylindrical permanent magnet that generates a uniform field in the cylinder bore, using the least amount of magnetic energy to do so. The remanence distribution of this magnet is derived and the generated field is compared to that of a Halbach cylinder of equal dimensions. The ideal remanence magnet is shown in most cases to generate a significantly lower field than the equivalent Halbach cylinder, although the field is generated with higher efficiency. The most efficient Halbach cylinder is shown to generate a field exactly twice as large as the equivalent ideal remanence magnet.