REBCO Tape Architecture

REBCO is a thin coated conductor: a micron of superconductor on a strong substrate, stabilized by copper — an architecture that shapes every magnet limit.

A coated conductor, not a wire

REBCO is manufactured as tape roughly 0.1 mm thick and a few millimeters wide. The superconducting layer is only about a micron thick, deposited on a buffer stack over a strong Hastelloy substrate, then capped with silver and copper for electrical and thermal stabilization. The mechanical strength comes almost entirely from the substrate and copper, not the ceramic superconductor.

Why the architecture matters

Three magnet-level facts follow directly from this cross-section. First, the current-carrying layer is thin and brittle, so the tape is strain-limited: exceed a few tenths of a percent strain and critical current degrades irreversibly. Second, the tape is anisotropic and its critical current depends on field angle relative to the tape face. Third, cooling and quench behavior are governed by the copper stabilizer, because the ceramic itself is a poor normal-state conductor.

Consequences for the breeder

• Winding must respect a minimum bend radius set by strain in the REBCO layer.
• Coil orientation is chosen so the worst field angle does not coincide with the peak-field region.
• Stabilizer thickness trades quench safety against current density in the thin center stack.
• Joints between tape lengths add resistance and are a reliability item, not an afterthought.

Every downstream magnet limit in this section — hoop stress, quench protection, screening currents, radiation tolerance — traces back to this layered geometry. The tape is strong in tension along its length and fragile across its thin dimension.

This page documents a design and simulation study, not a built machine. Construction begins Q2 2027; first-of-a-kind first tritium is targeted near 2030. Figures are computed, reproducible targets, not measurements.