{"paper":{"title":"How nonlinear spectral back transfer limits the temporal coherency of zonal modes?","license":"http://creativecommons.org/licenses/by/4.0/","headline":"Nonlinear spectral back-transfer of energy from zonal modes to turbulence sets the limit on their temporal coherency.","cross_cats":[],"primary_cat":"physics.plasm-ph","authors_text":"P H Diamond, Rameswar Singh","submitted_at":"2026-04-03T19:33:27Z","abstract_excerpt":"Zonal modes are central to magnetic confinement because their radial shears regulate turbulence and transport. While the generation of these flows is well understood, the mechanisms limiting their persistence in collisionless regimes remain unresolved. In this paper, we demonstrate that nonlinear spectral back-transfer of free energy from zonal modes to turbulence sets the fundamental limit on the temporal coherency of the shearing field. Back-transfer events induce stochastic phase and amplitude scattering of zonal shear that limits its auto-coherence time. Using gyrokinetic GENE simulations,"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"nonlinear spectral back-transfer of free energy from zonal modes to turbulence sets the fundamental limit on the temporal coherency of the shearing field","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That the back-transfer observed in GENE gyrokinetic simulations is the dominant physical mechanism limiting zonal flow coherence in real collisionless plasmas, rather than other unmodeled effects such as collisions or boundary conditions.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Nonlinear spectral back-transfer from zonal modes to turbulence limits shearing field coherence time, with suppression in negative triangularity plasmas increasing auto-coherence and Kubo number.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Nonlinear spectral back-transfer of energy from zonal modes to turbulence sets the limit on their temporal coherency.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"953f936dbc137a7df3e74ffec16790df87c61f921af2b34fab3f6a1d141767ab"},"source":{"id":"2604.03421","kind":"arxiv","version":2},"verdict":{"id":"eaafae36-24fd-4fce-b3ea-64c4d1b7f0bc","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-13T17:58:56.902638Z","strongest_claim":"nonlinear spectral back-transfer of free energy from zonal modes to turbulence sets the fundamental limit on the temporal coherency of the shearing field","one_line_summary":"Nonlinear spectral back-transfer from zonal modes to turbulence limits shearing field coherence time, with suppression in negative triangularity plasmas increasing auto-coherence and Kubo number.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That the back-transfer observed in GENE gyrokinetic simulations is the dominant physical mechanism limiting zonal flow coherence in real collisionless plasmas, rather than other unmodeled effects such as collisions or boundary conditions.","pith_extraction_headline":"Nonlinear spectral back-transfer of energy from zonal modes to turbulence sets the limit on their temporal coherency."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2604.03421/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"}