Working Principle

The magnet array used to allow the levitation of the Hyperloop pod is the linear Halbach array.

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Halbach Array

The linear Halbach array is a planar magnetic array capable of generating a magnetic field that is significantly stronger on one side. This is achieved by having a spatially rotating pattern of magnetisation.

How does levitation occur?

Two physics phenomena come into play when a magnet array is moved over a conductive surface such as a copper sheet — Lorentz force and magnetic drag.

As the magnet array travels over a conductive surface, eddy currents are induced within the surface. Each of these eddy currents creates a counter magnetic field which according to Lenz’s Law, opposes the change in magnetic field which caused it. This results in a drag force on the sheet, which opposes the movement of the magnet array over it.

Inducing the eddy currents in the surface also in turn cause an upward Lorentz force on the magnets moving over it, lifting them up. This is the force responsible for the magnetic levitation.

Hence, in order for the Hyperloop concept to work, magnetic drag has to first be overcome so that the pod can continue to accelerate forward over the conductive track. When the pod has achieved at a sufficiently high speed to result in a sufficiently high upward Lorentz force, it can then levitate. Second, the magnets to be used in the Hyperloop pod magnet arrays have to be strong enough to ensure effective magnetic levitation.

Combining the levitation provided by utilising the Halbach array and a constant propelling force forward, the Hyperloop pod is created.