Damage evolution and coupled stability in high-field REBCO magnets: from tape-level limits to damage-response pathways — A review

High-field tape-wound rare-earth barium copper oxide (REBCO) magnets involve coupled electrical, thermal, and mechanical processes, together with turn contact and protection conditions. Therefore, magnet-level degradation and event responses cannot be evaluated from short-sample conductor properties alone. Existing evidence is distributed among tape tests, winding-level measurements, transient event records, post-event damage inspections, and residual-function evaluations, while the connection between these evidence types remains incomplete. Consequently, neither the link from local conductor limits to winding-level event outcomes nor the implications of those outcomes for post-event damage and residual function have been resolved consistently. To address these gaps, this review organizes evidence from tape-wound inserts, pancake windings, and solenoids by evidence origin, confidence assigned to individual claims, and evidence transfer across different winding conditions. The reviewed studies show that tape-level limits vary with conductor architecture, loading history, specimen geometry, and measurement criterion, whereas processing, cooldown, contact, support, cooling, current bypass, and protection further redistribute current, heat, stress, and interfacial constraint at the winding scale. Recovery of a measured global function does not indicate that local damage is absent, and post-event damage morphology alone cannot fully determine the transient damage evolution. Available records support recoverable attenuation of specified functions and unstable amplification; time-resolved evidence for apparent damage arrest remains limited. This synthesis highlights the measurements and validation links needed for credible diagnosis, prediction of selected outputs, and evidence-informed decision support.