Systematic study of the resonancelike structure in the collisional flavor instability of neutrinos

Investigations on the resonancelike phenomenon in collisional flavor instability (CFI) of neutrinos, which were observed linear phase recently, are reported. We show that it occurs not only for isotropy-preserving modes as pointed out previous work but also isotropy-breaking and enhances growth rate CFI. Employing analysis nonlinear numerical simulations two-flavor scheme under relaxation approximation collision term, we discuss criterion phase, its effect subsequent evolution well influences homogeneity-breaking ($k\ensuremath{\ne}0$) perturbations anisotropy background structure. will touch idea cohabitation structure with fast-flavor conversion.