{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"96ebf5bc3aa8ac33b869c2ceec611f3c8c1cf756731f73582f9946f18409b23c","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["3f9cb9e54899c622391543a58ec33ec494935a3282953ed6eaecf59a4128ef56","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"192f11db60a5685465e831531694ef5250a4aa908034e170937ee36096a53362","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"beams.sc-magnets.hts-screening-currents","kind":"well-posed","literature_status":"open","n":"2","parents":[],"plain":"Magnets wound from flat high-temperature superconducting tape carry circulating currents inside the tape that distort the guiding field and drift in time.","posed_since":"","precise":"In REBCO coated-conductor coils (tape width $\\sim 0.4\\,\\mathrm{cm}$), screening currents induced during field ramps produce field harmonics and slow drifts well above the $10^{-4}$ relative field quality needed for beam optics, and add mechanical stress. Determine whether conductor layout (striated tapes, round twisted-tape cables) and ramp protocols can reduce screening-current field errors below $10^{-4}$ at fields $10^{5}\\ \\text{to}\\ 2 \\times 10^{5}\\,\\mathrm{G}$, and predict their decay in time from flux-creep parameters of the tape.","problem_ref":"3f9cb9e54899c622391543a58ec33ec494935a3282953ed6eaecf59a4128ef56","references":"","settled_by":"Magnetic measurements of field harmonics and their time decay in a REBCO dipole insert, matched by a model using independently measured tape properties.","status_note":"","title":"Field errors from screening currents in REBCO accelerator magnets","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"fbf513ccf787668e5466282db3784c5eab4cb5a80b6e917c10d0f91ec723de26","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"1f7863bb8fcdae6ab028de9ba9ffd1add370d4261347dd0d66bd44e685316054","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"GN0oxyTnGBxiLBSNWtaWtdJwfijG746vxIHz75Vto9EIoMTraqRCK--TLdF-Rqzdkdj7afoXvB0KlddJ9LksCg"},"schema":"pubphys.envelope/1"},"record_hash":"fbf513ccf787668e5466282db3784c5eab4cb5a80b6e917c10d0f91ec723de26","leaf_index":2522}