2025/07/09 by Joel Saucedo, Saucedo, Joel, Uday Lamba +3
Engineering · Materials Science · Physics and Astronomy · #FOS: Physical sciences #Fusion materials and technologies #Ion-surface interactions and analysis #Materials Science (cond-mat.mtrl-sci) #Plasma Physics (physics.plasm-ph) #Theoretical and Computational Physics
paper · pdf · doi:10.48550/arxiv.2507.07268
openalex publication_date 2025/07/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A persistent paradox complicates the study of plasma-irradiated thin films, where bimodal grain distributions and ambiguous scaling laws, roughly shifting between Φ-1/2 and Φ-1, or a general inverse dependence on plasma flux, are empirical yet remain theoretically unreconciled. Existing models fail to unify noise-driven evolution, defect saturation kinetics, and nucleation-loss balance within a single, self-consistent formalism. This work resolves these discrepancies by developing the first exact analytical theory for this system. We derive the closed-form steady-state grain area distribution, Pss(A), establish the precise dimensionless threshold for bimodality onset at Πc = 4/(3√(3)), and demonstrate that defect saturation physics mandate a universal ⟨ A ⟩ ∝ κ2 Φ-1 e+2Eb/kB Ts scaling law. The framework reveals how competition between stochastic impingement and deterministic growth triggers microstructure fragmentation, resolving long-standing ambiguities in irradiation-induced surface evolution and providing a predictive foundation for materials processing.