Transition Radiation of the Neutrino Toroid Dipole Moment

We discuss the transition radiation of a neutrino induced by its toroid dipole moment ($\tau$) when crossing the interface between two different media with different refraction indices. A neutrino of 1 MeV energy emits approximately $10^{-40}$ keV at $\tau=e\sqrt{2}G_F/\pi^2$. This effect depends very slightly on the neutrino mass and has a finite value in the massless limit.