Current generation in extragalactic jets by Cherenkov damping of magnetohydrodynamic waves

The Kelvin-Helmholtz instability leads to the excitation of MHD waves as highly ionized extragalactic jets (EJs) pass through a magnetic field. The present consideration of magnetosonic and surface waves' damping in such essentially collisionless plasmas notes that electric currents of a magnitude rendering them dynamically important can result from transit-time magnetic damping. A model is proposed which admits a distributed generator to act along the EJ's length, and avoids problems of previous models requiring a current generator at the galactic nucleus which maintains a current over the length of the EJ. 100 refs.