  We analyze the role of collisional effects on the coupling between
ion-acoustic waves and neutrino flavor oscillations, discussing its relevance
for plasma instabilities in extreme plasma environments like in type II
supernovae, where intense neutrino bursts exist. Electrons (leptons) are
coupled to the electron-neutrino fluid through the weak Fermi force, but the
electron-neutrinos are allowed to convert to other neutrino flavors and
vice-versa. Due to the typically slow frequency of neutrino flavor
oscillations, many orders smaller than e.g. the plasma frequency, an effective
energy transfer between plasma waves and neutrino flavor oscillations take
place at the low-frequency electrostatic branch, viz. the ion-acoustic mode. We
show the destabilization of ion-acoustic waves in dense astrophysical
scenarios, with a focus on the collisional effects mediated by electron-ion
scattering. The maximal instability growth-rate is evaluated and compared to
characteristic inverse times of type II supernova explosions. The results can
be used for independent experimental verification of the non-zero neutrino
mass, in a plasma physics context.
