<p>Resonant laser fluorescence on the Stark structure of levels of fast atoms in diagnostic beams in a nuclear fusion plasma has been theoretically studied. A nonstationary kinetic model of the population of Stark sublevels has been developed to describe resonant laser fluorescence depending on the parameters of the diagnostic beam, plasma, laser pulse, and time. The change in the fluorescence signal at the beam depending on the time and density of the plasma has been examined. The suppression of resonant laser fluorescence under both broadband and selective laser pumping of Stark sublevels with an increase in density and the tendency of nonstationary dynamic populations to statistical values, which follow from the Schrödinger theory of the Stark effect and do not depend on the density and nature of the equilibrium between the levels, has been revealed. The results are of general physical interest in the light of experimental confirmation of Schrödinger quantum theory of hydrogen-like systems, as well as in view of the relevance of the search for new possibilities for laser-beam plasma diagnostic.</p>