https://hal-cea.archives-ouvertes.fr/cea-01180981Dupuy, HélèneHélèneDupuyCentre local de développement des Collines-de-l'Outaouai, Cantley - Centre local de développement des Collines-de-l'Outaouai, CantleyBernardeau, FrancisFrancisBernardeauIPHT - Institut de Physique Théorique - UMR CNRS 3681 - CEA - Commissariat à l'énergie atomique et aux énergies alternatives - Université Paris-Saclay - CNRS - Centre National de la Recherche ScientifiqueOn the importance of nonlinear couplings in large-scale neutrino streamsHAL CCSD2015[PHYS] Physics [physics]De Laborderie, Emmanuelle2015-07-28 16:20:422021-12-13 09:16:012015-07-28 16:20:42enPreprints, Working Papers, ...1We propose a procedure to evaluate the impact of nonlinear couplings on the evolution of massive neutrino streams in the context of large-scale structure growth. Such streams can be described by general nonlinear conservation equations, derived from a multiple-flow perspective, which generalize the conservation equations of non-relativistic pressureless fluids. The relevance of the nonlinear couplings is quantified with the help of the eikonal approximation applied to the subhorizon limit of this system. It highlights the role played by the relative displacements of different cosmic streams and it specifies, for each flow, the spatial scales at which the growth of structure is affected by nonlinear couplings. We found that, at redshift zero, such couplings can be significant for wavenumbers as small as $k=0.2\,h$/Mpc for most of the neutrino streams.