2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/85302A closed expression for the momentum evolution of a test particle in weakly-coupled plasma is derived, starting from quantum many particle theory. The particle scatters from charge fluctuations in the plasma rather than in a sequence of independent binary collisions. Contrary to general belief, Bohr's (rather than Bethe's) Coulomb logarithm is the relevant one in most plasma applications. A power-law tail in the distribution function is confirmed by molecular dynamics simulation.5 pages, 2 figuresPlasma PhysicsGeneral Physicstext