{"paper":{"title":"Universal behaviour of $\\alpha$-viscosity in black hole accretion discs","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.HE","authors_text":"Axel Brandenburg, Debora Lan\\v{c}ov\\'a, Ewa Szuszkiewicz, Ji\\v{r}\\'i Hor\\'ak, John C. Miller, Maciek Wielgus, Marek A. Abramowicz","submitted_at":"2026-03-11T17:22:12Z","abstract_excerpt":"The Shakura-Sunyaev $\\alpha$-viscosity coefficient, defined as the ratio of total stress to total pressure, $\\alpha= \\mathbb{T}/p$, began to play an important role in the development of accretion disc theory in the early 1970s. The origin of the turbulence that causes the stress $\\mathbb{T}$ was unknown at that time; Shakura and Sunyaev assumed $\\alpha=$\\,const. Today we know that this was not quite realistic -- modern general relativistic magneto-hydrodynamic simulations (GRMHD) of black hole accretion discs have revealed that $\\alpha$ changes by about an order of magnitude within the disc, b"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2603.10997","kind":"arxiv","version":2},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2603.10997/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}