Maglev
Personal note: I bought a printer recently and printed this research, making my own notes while deep-diving into a topic that fascinated me as a kid.
Fundamentals
Magnetic levitation relies on magnetic forces to counteract gravity without physical contact. Key principles include the Meissner effect—when a superconductor is cooled below its critical temperature, it expels internal magnetic fields, causing a magnet to levitate above it. In type-II superconductors, partial penetration of flux in discrete tubes leads to flux pinning (quantum locking), which can “lock” a superconducting object in space above a magnet. Two primary maglev methods: electromagnetic suspension (EMS), with actively controlled electromagnets attracting the vehicle to a ferromagnetic track from below, and electrodynamic suspension (EDS), using superconducting magnets or induced currents for repulsion. EMS requires constant feedback control; EDS is intrinsically stable at operational speed with larger gaps. Diamagnetic levitation—materials like bismuth or graphite generating weak opposing fields—can levitate even a frog at ~10 Tesla.
Current state
Shanghai Transrapid runs ~30 km at 430 km/h. Japan’s SCMaglev (EDS) hit 603 km/h in testing; Chūō Shinkansen Tokyo–Nagoya is planned for 2027. China unveiled a 21 m HTS maglev prototype (620 km/h design, liquid nitrogen cooling). Beyond trains: magnetic bearings in turbopumps and flywheel storage, MRI scanners, magnetically levitated heart pumps (HeartMate 3). Hyperloop is essentially maglev in a low-pressure tube. Fusion tokamaks (ITER, SPARC) use enormous superconducting magnets to confine plasma; CFS’s 20 T HTS coil demo in 2021 was a milestone.
Barriers and outlook
Infrastructure cost is extreme (Tokyo–Nagoya ~$50B+). Maglev competes with high-speed rail and aviation; the sweet spot is routes where ultra-high speed beats air door-to-door. HTS materials and cryogenics are improving. By 2030 we may see net-energy fusion demos and more HTS maglev pilots. The common thread: removing physical constraints (friction, wear, gravity) with magnetic force to enable performance not possible with traditional mechanics.