2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/48720We discuss the Cherenkov process $ν\toνγ$ in the presence of a homogeneous magnetic field. The neutrinos are taken to be massless with only standard-model couplings. The magnetic field fulfills the dual purpose of inducing an effective neutrino-photon vertex and of modifying the photon dispersion relation such that the Cherenkov condition $ω<|{\bf k}|$ is fulfilled. For a field strength $B_{\rm crit}=m_e^2/e=4.41\times10^{13} Gauss$ and for $E=2m_e$ the Cherenkov rate is about $6\times10^{-11}s^{-1}$.Talk given at 4th SFB-375 Ringberg Workshop on Neutrino Astrophysics Ringberg Castle, Tegernsee, Germany, 20-24 Oct 1997High Energy Physics - Phenomenologytext