Japan is using electromagnet technology across several ambitious projects, but the most prominent is the Chuo Shinkansen, a superconducting maglev train designed to travel between Tokyo and Nagoya at speeds up to 500 km/h (311 mph). Beyond transportation, Japanese institutions and companies are building some of the world’s largest superconducting magnets for nuclear fusion, firing neutrino beams across hundreds of kilometers using particle accelerators, and developing electromagnetic devices to clean up space debris.
The SCMAGLEV Bullet Train
The Chuo Shinkansen is Japan’s flagship electromagnet project. Operated by Central Japan Railway Co. (JR Tokai), this train uses superconducting magnets to levitate above a guideway, eliminating friction and enabling extraordinary speed. The onboard magnets use coils made from a niobium-titanium alloy, cooled with liquid helium to minus 269°C (minus 452°F). At that temperature, the coils enter a superconducting state where electrical resistance drops to zero, producing an extremely powerful and stable magnetic field.
The train doesn’t just float. It accelerates, decelerates, and stays centered in its guideway entirely through magnetic forces generated between the onboard magnets and coils embedded in the guideway walls. There are no wheels touching the ground at operating speed, no engine in the traditional sense. The system set a world speed record of 603 km/h (375 mph) in 2015, recognized by Guinness World Records. Testing also confirmed stability when two trains passed each other at a combined relative speed of 1,003 km/h (623 mph).
The project has hit significant delays. JR Tokai originally aimed to begin service in 2027, but tunnel excavation problems and ballooning costs pushed the timeline back. As of late 2024, the company estimated a 2035 opening at the earliest, with total construction costs reaching 11 trillion yen (roughly $73 billion). Company officials cautioned that even 2035 is a planning estimate, not a firm date.
Giant Magnets for Nuclear Fusion
Japan is manufacturing some of the largest superconducting magnets ever built for ITER, the international fusion reactor under construction in southern France. ITER aims to demonstrate that nuclear fusion, the process that powers the sun, can produce net energy on Earth. Containing the superheated plasma inside the reactor requires extraordinarily powerful magnetic fields, and that’s where Japan’s contribution comes in.
Japanese manufacturers, led by Mitsubishi Heavy Industries, are producing D-shaped toroidal field coils that stand 17 meters high and weigh close to 350 tonnes each. These are among the largest superconducting magnets ever constructed. The production effort, from initial design to completion, spanned three decades, involved more than a thousand people, and mobilized 50 different companies and institutions. Multiple coils still need to be delivered to the ITER site, with shipments continuing from the Mitsubishi facility in Futami, Japan.
Steering Neutrino Beams With Superconducting Magnets
At the Japan Proton Accelerator Research Complex (J-PARC) in Tokai, a 150-meter-long superconducting beam line uses 28 powerful electromagnets to bend a proton beam by 80 degrees. The goal is to aim a stream of neutrinos, nearly massless subatomic particles, at the Super-Kamiokande detector located 295 kilometers away. This setup is part of the T2K experiment, which studies how neutrinos change form as they travel, a phenomenon that could help explain why the universe contains matter at all.
Each superconducting magnet in the beam line produces a magnetic field of 2.6 tesla (roughly 50,000 times stronger than Earth’s magnetic field) and operates at a current of over 7,300 amps. The magnets serve double duty: a single magnet can both bend the beam and focus it, depending on its orientation. All 28 magnets run in series from a single power supply, with smaller steering magnets made from niobium-titanium wire providing fine corrections to keep the beam precisely on target.
Electromagnetic Tethers for Space Debris
Japan is developing a device that uses Earth’s own magnetic field to pull defunct satellites out of orbit before they become dangerous space junk. The project, a collaboration between JAXA and the company ALE, uses an electrodynamic tether: a long conductive cable that extends from a satellite after its mission ends. As the tether moves through Earth’s magnetic field, it generates a force that gradually lowers the satellite’s orbit until it reenters the atmosphere and burns up.
What makes this version distinctive is the use of a carbon nanotube cathode, an electron-emitting component that makes the tether system more effective at generating the electromagnetic drag needed for deorbiting. JAXA describes it as the world’s first post-mission disposal device combining these two technologies. The concept targets the rapidly growing population of satellites in low Earth orbit, aiming to prevent the kind of chain-reaction collisions that could make certain orbits unusable.
Grid-Scale Energy Storage
Japan has tested superconducting magnetic energy storage (SMES) systems that store electricity directly in the magnetic field of a superconducting coil. Unlike batteries, which convert energy through chemical reactions, SMES systems can release large amounts of power almost instantly, making them useful for smoothing out sudden voltage drops or compensating for fluctuating power loads.
A 5 MVA system was deployed at a large LCD television manufacturing plant in Japan to protect against voltage dips from lightning strikes, and its effectiveness was confirmed in field testing. That led to a scaled-up 10 MVA system at the same site. A larger prototype, rated at 10 MVA and 20 MJ, was tested on an actual power grid that included hydroelectric generators, where it compensated for the erratic power demands of a metal rolling factory. Japanese engineers have concluded that systems in the several megawatt-hour range are technically feasible for frequency control and load balancing on commercial power grids.
Quantum Computing and Medical Imaging
Japan’s RIKEN research institute is working on superconducting quantum computers, where information is processed by tiny circuits cooled to near absolute zero. Researchers there have fabricated Josephson junctions, the core switching elements in superconducting quantum processors, from a single layer of tungsten telluride. This material can be switched between superconducting and normal states using electric fields alone, which could simplify the construction of future quantum chips.
On the medical side, Japan’s National Institute for Physiological Sciences operates a 7-tesla MRI scanner, a machine with a magnetic field roughly twice as strong as the MRI scanners found in most hospitals. At this field strength, the scanner can detect individual types of molecules in brain tissue, including glucose, without injecting any tracer substances. Researchers are using it to measure concentrations of specific brain chemicals tied to neurological function, and a custom 24-channel head coil was designed in collaboration with Japanese engineers for brain imaging studies comparing humans and primates.