{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"561b90aff17734e8d09c9bceed8568f9ae6a8655861de4ce54cd0a12b6aa9d29","created":"2026-10-03T07:17:56Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"69beb7bc5050a84abc82e3f08f4dd1d16250ef852199d64877b95a6eedb727c8","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"beams.collective-instabilities.landau-damping-latency","kind":"well-posed","literature_status":"partially-resolved","n":"1","parents":[],"plain":"In the LHC, beams calculated to be stabilized by octupole magnets sometimes become unstable after minutes, suggesting slow erosion of the stabilizing frequency spread.","posed_since":"","precise":"LHC transverse instabilities appeared with latencies of minutes at octupole strengths predicted stabilizing by linear Landau-damping theory. Determine whether diffusion driven by transverse-feedback and external noise, which flattens the tails of the particle distribution and shrinks the stability diagram, accounts quantitatively for measured latencies and octupole thresholds.","problem_ref":null,"references":"","settled_by":"Controlled noise-injection experiments in which measured latency versus noise level matches a diffusion model with no fitted parameters.","status_note":"Noise-driven erosion of Landau damping was proposed and supported by simulations and dedicated LHC experiments around 2019-2021; predictive accuracy for operation is limited.","title":"Instabilities that appear minutes after a beam is predicted stable","topic_ref":"dd60e631adb08b9b18495c7a3ab1cfd2ffd7375b33108ba5cf5ec6cce7af2868"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"027b04e5347952416fc0d94572dd1726eb048fd18e10456b1f03e510581e86c2","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"4332177d7843894eaab7ce4c59270a148d13394be54d5349c9ccf210b731100b","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"VZHQPk_9soeJmj8qTeuDfC8RNVQqsXMAmN9HqUTcKcqoIOkKa_tAXBT7iMjG_AxVWlT1ZKoUNOP7CW-1qo3kCQ"},"schema":"pubphys.envelope/1"},"record_hash":"027b04e5347952416fc0d94572dd1726eb048fd18e10456b1f03e510581e86c2","leaf_index":657}