Have you ever tried to get one magnet to float on top of another? Given, that they can repel each other, surely it must be possible to set things up so that the eerie force of gravity downwards is exactly balanced by the magnetic push upwards? You can keep trying to do this but unless you use other objects to keep the magnets in place you will find this just isn’t possible….or is it?
Some of the ghoulish electric and magnetic forces which are required in particle accelerators are big, really big. We generally make the electric and magnetic fields (forces) with an electric current, but the electric current in a device is limited by the resistance of that device. However, if we cool the device to a really low temperature the resistance all but vanishes meaning we can transport really big electric currents, a phenomenon called superconductivity. This in turn means we can generate the strong electric and magnetic fields which are required in high energy particle accelerators.
CI scientists and engineers develop underpinning technologies such as rf cavities, vacuum systems and magnets, as well as beam diagnostics techniques to support work on these high energy machines.
We also use superconductors in ultrasensitive monitors as they can be used to measure the smallest magnetic fields. CI experts working with CERN colleagues have developed a new type of monitor for low energy antimatter beams, where nano-amp beams can be measured non-invasively, the cryogenic current comparator.
But what has this got to do with floating magnets? Well, we can make some materials become superconducting at cold temperatures and then see some very spine-tingling phenomena. When superconducting materials transition to the superconducting state any magnetic field in the area is expelled from the superconductor. This field expulsion will repel a nearby magnet and a magnet can be made to float above the superconductor.