{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"382acd891bbbcd31f7a8ce55109203c1e72cecdd70cf0b7933b100e352cb9971","created":"2026-10-03T07:17:56Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"15fe2c5e8d424014e43a435e1909d3de1523f3b95ef8b25210ddcf9d053e9de2","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":"1","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 $1e-4$ 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 $1e-4$ at fields $1e5\\ \\text{to}\\ 2e5\\,\\mathrm{G}$, and predict their decay in time from flux-creep parameters of the tape.","problem_ref":null,"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":"a83e07dd68407ac5bcfad93a1a605a4cf0470772a34c776e66dd884c34f68340"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"3f9cb9e54899c622391543a58ec33ec494935a3282953ed6eaecf59a4128ef56","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"82abad8b7da7fc3a02f268d4976c7afa8835e03729a194d0566aacdcf1378aa8","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"2BC44HhBERxZ-DtwkT_AS93i11JDSi3shAmJImo6mGurLGth1I3gRiAJom7WbTCpi2Xt9V0E_acaeOpCYmF0Dg"},"schema":"pubphys.envelope/1"},"record_hash":"3f9cb9e54899c622391543a58ec33ec494935a3282953ed6eaecf59a4128ef56","leaf_index":696}