2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/229434We examine a family of microscopic models of plasmas, with a parameter $α$ comparing the typical distance between collisions to the strength of the grazing collisions. These microscopic models converge in distribution, in the weak coupling limit, to a velocity diffusion described by the linear Landau equation (also known as the Fokker-Planck equation). The present work extends and unifies previous results that handled the extremes of the parameter $α$, for the whole range (0, 1/2], by showing that clusters of overlapping obstacles are negligible in the limit. Additionally, we study the diffusion coefficient of the Landau equation and show it to be independent of the parameter.22 pages, 8 figures, accepted to Communications in Pure and Applied AnalysisMathematical PhysicsProbability82B40; 82D10; 60K35text