Demo4 magnet tests reach 11.8 tesla at -243 °C

Tokamak Energy/Demo4

Tokamak Energy's Demo4, its full set of 14 toroidal and 2 poloidal superconducting magnets in a tokamak layout, reached 11.8 tesla at -243°C. Testing magnets together is critical because their fields interact in ways single-magnet tests cannot show; higher-field tests were planned for early 2026.

• Demo4 is the first full HTS magnet system demonstration at tokamak-relevant fields.
• Reached 11.8 tesla at -243°C.
• System-level testing captures magnet interactions that single-magnet tests miss.
• Validates high-temperature superconductor technology for fusion power plants.