Electroweak plasma instabilities and supernovae

Under violent astrophysical conditions, intense fluxes of neutrinos can dri ve a novel class of plasma instabilities: the electroweak versions of the s tandard electron- and photon-driven forward scattering instabilities. Emplo ying the relativistic kinetic equations for the neutrinos interacting with a plasma via the weak interaction force, we explore the different collectiv e plasma instabilities driven by neutrinos. We examine the anomalous energy transfer between the neutrinos and the background plasma via excitation of electron plasma waves (neutrino streaming instability), and the generation of quasi-static B fields (electroweak Weibel instability). The relevance o f the electroweak plasma instabilities for the extreme conditions occurring in the lepton era of the early universe, supernovae II, and gamma ray burs ters is pointed out. The impact on type II supernovae dynamics is examined, and estimates for the energy deposited via collective mechanisms behind th e outgoing shock are presented. We show that electroweak plasma instabiliti es might play an important role in the re-energization of the stalled shock in SNe II.