China Now Has the World's Strongest Magnet

Aug 29, 2022 | By NEWSWEEK

A lab in China has produced the most powerful steady magnetic field in the world.

The Steady High Magnetic Field Facility (SHMFF) in Hefei, China, recorded a field strength of 45.22 Tesla (T) on August 12 from its high-powered hybrid magnet.

The previous record was set in 1999 at MagLab in the U.S., which measured a stable magnetic field at 45 T.

The highest magnetic field strength ever created was measured at 1,200 T in 2018. However, this field was not stable.

Magnets are metals that naturally produce magnetic fields. Usually iron, nickel or cobalt, the magnetic field lines of each atom within a magnet are aligned, combining to produce an overall field, exiting at the object's north pole and entering at its south pole.

Electromagnets are found everywhere, from the ones you might see at a scrapyard to MRI machines. They are essentially coils of wire, usually copper, with electricity passing through them. Since moving electric charges create magnetic fields, when electricity flows through the coils, a magnetic field is created. The strength of a magnetic field is measured in Tesla: a typical fridge magnet has a field strength of around 0.001 T.

The Chinese magnet was built in 2016, and originally produced a field strength of 40 T. Since then, scientists have worked to increase its power.

"To achieve higher magnetic field, we innovated the structure of the magnet, and developed new materials," said Professor Kuang Guangli, the academic director of the High Magnetic Field Laboratory of Hefei Institutes of Physical Science, Chinese Academy of Sciences (CHMFL), in a statement.

A hybrid magnet, like both the landmark SHMFF magnet and the 1999 record holder, uses a combination of two different methods to create a magnetic field. According to MagLab, a hybrid magnet uses superconducting wire that doesn't require large amounts of power to create a magnetic field, however, once the wire stops becoming a superconductor, the magnetic field cannot get stronger.

To increase the field strength even further, a hybrid magnet subsequently uses resistive magnets, called Bitter discs—which use a large amount of electric power and are expensive to run as a result—inside the wire at the highest field areas. This hybrid technology allows the maximization of field strength.

"That way we can get to the highest fields with a minimum use of electric power," MagLab writes on its website.

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