Magnet Systems

Magnets are essential, enabling technology. They confine hot plasmas and significantly impact the plasma initiation, heating, control, and sustainment systems. Magnetic field strength limits the achievable plasma pressure needed for fusion – higher field would allow more compact devices and could significantly ease control requirements. Today’s experiments, and those planned, including ITER, use superconducting (SC) magnet technology that is decades old. The SC magnet system of large-scale fusion devices is about one-third of the core machine cost. Future reactors must be built with the best available superconductor technology since most magnetic configurations for a practical fusion reactor requires superconducting magnets.

Revolutionary new HTS materials such as Yttrium-Barium-Copper-Oxide (YBCO) are sufficiently advanced for next-step fusion applications. Besides having a high critical temperature, these materials can operate at extremely high magnetic fields, offering a substantial increase in plasma performance.

An integrated program of advanced magnet R&D is focused on developing High-Temperature Superconductor (HTS) materials and magnet systems. The goal is to develop fusion devices that have high performance, high reliability, availability and maintainability with acceptable cost—potentially a “game changer” in several respects. In the nearer term, the superconducting magnet development program offers flexible experimental scale devices which can be operated in the steady state, including tokamaks, stellarators, and other non-planar geometries for 3-D magnetic configuration devices.