Topology-dependent levitation-force degradation induced by angular interfacial gaps in segmented YBCO bulks

High-temperature superconducting levitation is a promising technology for future high-speed transportation. This numerical study investigates levitation-force degradation caused by an angular interfacial gap in a segmented two-YBCO-bulk configuration and its dependence on the spatial matching between permanent-magnet-guideway (PMG) field topology and gap location. Among the three guideways considered, the flux-concentrating PMG shows the largest reduction in peak levitation force (24.58% at θ = 5°), whereas the Halbach PMG shows the smallest reduction (7.12%). Formation of a finite gap changes the contacting interface into two exposed electromagnetic boundaries, reconstructs the shielding-current paths, generates an unfavorable local Lorentz-force contribution near the gap, and weakens the dominant positive-force region. The large initial reduction for the flux-concentrating and surface-magnetized PMGs is therefore attributed primarily to loss of electromagnetic continuity when the finite gap first forms; subsequent increases in angle have a weaker secondary effect. The results provide quantitative guidance for the segmented HTS configurations investigated here. Direct quantitative extrapolation to microscopic defects is not intended because their length scales, aspect ratios, material properties, and local boundary conditions may differ.