halbach array display photo

How Does a Halbach Array Work? The Complete Guide

Have you heard about Halbach arrays but still aren’t quite sure what they are or how they work? If so, you’ve come to the right place.

In this complete guide, as a Halbach array manufacturer, we’ll cover everything you need to know about Halbach arrays including:

  • What a Halbach array is
  • How does a Halbach array work
  • Key components and operating principles
  • Real-world applications
  • Advantages and limitations

By the end, you’ll have a solid understanding of what these unique magnetic assemblies are all about and how they can be used.

So if you’re ready to become a Halbach array expert, let’s get started!

halbach array display photo

What Is a Halbach Array?

Halbach array is a special arrangement of permanent magnets that concentrates magnetic field on one side while cancelling it out on the other.

This is achieved through precise positioning that follows a rotating pattern of magnetization orientation.

Here’s a simple visual representation:

Halbach Array Diagram

On the left, you can see the standard magnetic field created by a single cuboidal magnet. The field flows evenly from the north pole at the top to the south pole at the bottom.

The image on the right shows a Halbach array made up of five cuboidal magnets. But instead of all having the same pole facing upward, the magnetization direction rotates by 90 degrees from one to the next.

This arrangement augments the magnetic field strength on the top side of the array. But on the bottom side, the field is nearly eliminated.

Now that’s just a basic conceptual diagram. As we’ll see soon, real-world Halbach arrays involve more complex geometries and very precise magnet positioning.

But fundamentally, these arrays all operate on the same principle of concentrated one-sided flux made possible by spatially rotating fields.

So in short:

A Halbach array is a series of permanent magnets arranged to focus magnetic field strength to one side through precise rotation of magnetization orientation.

How Does a Halbach Array Work?

A Halbach array is a special arrangement of permanent magnets that creates a unique magnetic field distribution. Here’s how it works:

  1. Magnet arrangement: A Halbach array consists of a series of permanent magnets arranged in a specific pattern. Each magnet is oriented with its magnetic field rotated by 90 degrees relative to its neighbors.
  2. Field concentration: This arrangement causes the magnetic fields to combine constructively on one side of the array, while canceling out on the opposite side.
  3. One-sided flux: The result is a “one-sided flux” distribution, where the magnetic field is significantly stronger on one side of the array and nearly zero on the other side.
  4. Field strength: On the strong side, the magnetic field can be up to twice as strong as it would be with a uniformly magnetized structure.
  5. Magnet types: Halbach arrays can be created using various types of permanent magnets, including neodymium (NdFeB) magnets.
  6. Configurations: Halbach arrays can be arranged in linear (straight) or circular configurations, allowing for different applications.

Key Components of a Halbach Array

Now that we’ve covered the history behind these unique magnet configurations, let’s examine the key components that make up a Halbach array.

Permanent Magnets

The magnetic field in a Halbach array comes from permanent magnets. Materials like neodymium iron boron (NdFeB) or samarium cobalt (SmCo) are typical choices.

Permanent magnets are preferred over electromagnets for several reasons:

  • Compact SIZE: Permanent magnets allow Halbach arrays to be highly compact and portable since no external power supply is required.
  • High efficiency: Very little energy loss occurs across an air gap.
  • Stability: The magnetization remains constant over time rather than fluctuating like a powered electromagnet.

Of course, the specific dimensions, grade, and composition of the permanent magnets depends on the target application. We’ll go over some real-world examples soon.

But fundamentally, all Halbach arrays get their magnetic muscle from precision-arranged permanent magnet elements.

Rotating Magnetization

The orienting pattern of magnetic poles is a Halbach array’s defining feature. By rotating pole directions from one magnet cube to the next, external flux can be focused to one side.

Consider the progression below:

  1. With all north poles facing up, the field on both sides is uniform but strong enough to have practical applications.
  2. A slight augmentation occurs on top when every second cube flips south pole up, creating cancellation on the bottom side.
  3. This one-sided concentration effect intensifies further when each block steps by only 90 degrees.
  4. Expanding this staggered stepping to many magnet cubes maximizes the planer Halbach array outcome.

Through gradual rotation, more and more flux gets pulled into a powerful unilateral field above the array while virtually zeroing out on the underside.

Increased focusing capacity does necessitate tighter manufacturing precision as assemblies grow. But the end results make properly-tuned Halbach arrays extremely useful compared to traditional static magnet arrangements.

Operating Principles

Now that you understand the key components, let’s examine how these components produce a Halbach array’s signature abilities by looking at the operating principles.

Specifically, the concentration of magnetic field to a single side occurs due to two main effects:

Flux Bundling

Aligning the north pole of one cube with a south pole diagonally pulls in and “bundles” magnetic field lines. Rather than spreading out in all directions like a typical bar magnet’s flux, the bundled flow gets directed through the air above.

You can visualize this connect-the-dots concentration of field lines occurring across an entire array build-up.

Flux Cancellation

At the same time as flux bundling augmentation occurs on one side, cancellation happens on the other side due to facing pole arrangements.

When north meets north—or south meets south—the fields directly negate rather than stacking constructively.

This complementary yin-yang duality gives rise to the characteristic single-face concentration as the flux bundling and cancellation effects combine.

Through meticulous rotation and alignment during assembly, sizes suitable for practical applications can be achieved. And that brings us to some of the incredible technologies Halbach arrays are making possible!

Practical Applications of Halbach Arrays

Given their ability to produce extremely strong one-sided magnetic fields from compact permanent magnet volumes, Halbacn array applications are diverse and growing.

Let’s look at some areas leveraging these special magnet configurations.

Particle Accelerators and Beamlines

As highlighted earlier, the original motivation for Halbach’s invention involved focusing particle beams. So it’s no surprise that accelerators and beamlines continue relying on his breakthrough.

Whether steering electronproton, or ion beams, Halbach arrays enable state-of-the-art output through field confinement.

The compact designs also minimize expensive infrastructure materials that would otherwise be required.

Some notable examples include synchrotrons like the Advanced Photon Source at Argonne National Lab and numerous free-electron lasers globally.

Such cutting-edge installations take “manipulating beams and bottling light” to the extreme limits. And ultra-precise Halbach assemblies help them get there.

Electric Motors

Brushless DC motors achieve new levels of torque versus size when designed around a Halbach cylinder rotor.

With the magnetic field concentrated on the interior facing the stator windings, increased intensity squeezed into a smaller overall diameter comes largely from eliminated back iron.

Lower weight along a high power-to-volume ratio also enables faster acceleration ideal for applications like drone propulsion.

Eliminating iron losses similarly boosts energy efficiency. So the automotive industry has been moving to adopt the technology as vehicle electrification continues gaining momentum.

Magnetic Levitation Transport

Japan has been operating several maglev train services for years, but the search for economically feasible infrastructure remains challenging globally.

One promising solution that could finally help make this futuristic mode of transport commonplace is called Inductrack.

It uses passive Halbach arrays on the underside of carriages gliding over track-mounted conductor loops. Thanks to the focused field geometry, only a narrow clearance gap minimizes construction and energy costs under real running conditions.

So while still undergoing development, Inductrack holds promise for revolutionizing mass transit in the coming years.

Rotating Machinery

Beyond motors themselves, Halbach arrays bring advantages to various rotating equipment through “magnetic gear” arrangements.

These non-contact torque couplers avoid wear while enabling precise speed or motion control. That expands design possibilities for automated factory and processing installations demanding reliability, precision, and maintenance access.

Applications range from robot articulation joints to agitators for food or pharmaceutical products. Eliminating lubrication needs also helps industries leverage magnetic gears in cleanrooms and sterile areas.

And Many More Applications

This has just been a small sampling of Halbach array implementations found improving technologies today.

Inventive engineers keep finding new ways to leverage their advantages.

Some other uses include:

  • Secure magnetic locks
  • Rotating data bits on storage platters
  • MRI machines
  • Scientific instrumentation
  • Beam directing optics
  • Cloaking devices

Continued discovery of niche applications seems destined thanks to the capabilities unlocked from Halbach’s breakthrough insight.

Benefits and Limitations of Halbach Arrays

Now that you’ve seen some of the incredible implementations, you may be wondering about the pros and cons of Halbach arrays compared to other magnet designs.

Let’s recap some of the major benefits that make them shine along with a few limitations to keep in mind.


  • One-sided flux concentration multiples field strength
  • Permanent magnetization eliminates power requirements
  • Compact size versus electromagnets
  • Adjustable dimensions for precise tuning
  • Removes need for bulky ferrous back-iron
  • Passive and electrically non-conductive


  • Complex manufacturing and calibration
  • Brittle NdFeB materials require careful handling
  • Limited temperature operation range
  • Expensive rare-earth materials
  • Can vibrate loose under extreme conditions

Considering these characteristics during your design process allows you to leverage Halbach benefits while accounting for constraints.

And understanding array operation from the grounjd up makes it easier avoiding surprise limitations.


We’ve covered a lot of ground going from a simple definition to an overview of state-of-the-art functionality.

To recap, a Halbach array is:

A series of permanent magnets arranged to concentrate magnetic field strength to one side through precise rotation of magnetization orientation.

Initial discovery of their operating principles by Mallinson and Halbach lead to ongoing innovation as more applications leverage unilateral fields.

Careful orientation steps up flux on a single face while cancelling it on the opposite side. And doing this to scale enables amazing technologies through compact permanent magnetic assemblies.

So next time you hear about something involving a Halbach array, you can appreciate exactly how rotating precise fields of magnetism make it possible!

I hope you’ve enjoyed this introduction finding it both informative and inspiring. The unique concepts behind Halbach array operation open many doors as engineers and physicists continue probing their potential.

Let me know in the comments if you have any other questions about how these special magnet arrangements work or what they might enable next!

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