Neutrino kinetics in dense astrophysical plasmas

Starting from the effective potentials describing the interaction of a sing le neutrino with a background species and the concept of ponderomotive forc e of neutrinos, we develop a collisionless relativistic kinetic theory for neutrinos coupled with a background medium. This formalism provides the bas ic tool for the physics of collective neutrino-plasma interactions. Compari son with equivalent kinetic equations derived using the methods of finite-t emperature quantum field theory is presented. Astrophysical scenarios in wh ich collective neutrino-plasma interactions can play an important role are discussed.