{ "id": "2308.01694", "version": "v1", "published": "2023-08-03T11:24:21.000Z", "updated": "2023-08-03T11:24:21.000Z", "title": "Asymptotic Behavior of Degenerate Linear Kinetic Equations with Non-Isothermal Boundary Conditions", "authors": [ "Armand Bernou" ], "comment": "35 pages, 1 table. Comments are welcome", "categories": [ "math.AP", "math-ph", "math.MP" ], "abstract": "We study the degenerate linear Boltzmann equation inside a bounded domain with the Maxwell and the Cercignani-Lampis boundary conditions, two generalizations of the diffuse reflection, with variable temperature. This includes a model of relaxation towards a space-dependent steady state. For both boundary conditions, we prove for the first time the existence of a steady state and a rate of convergence towards it without assumptions on the temperature variations. Our results for the Cercignani-Lampis boundary condition make also no hypotheses on the accommodation coefficients. The proven rate is exponential when a control condition on the degeneracy of the collision operator is satisfied, and only polynomial when this assumption is not met, in line with our previous results regarding the free-transport equation. We also provide a precise description of the different convergence rates, including lower bounds, when the steady state is bounded. Our method yields constructive constants.", "revisions": [ { "version": "v1", "updated": "2023-08-03T11:24:21.000Z" } ], "analyses": { "subjects": [ "35B40", "35Q20", "82C40", "82D05" ], "keywords": [ "degenerate linear kinetic equations", "non-isothermal boundary conditions", "asymptotic behavior", "steady state", "cercignani-lampis boundary condition" ], "note": { "typesetting": "TeX", "pages": 35, "language": "en", "license": "arXiv", "status": "editable" } } }