PARTICLE-ACCELERATION IN EXTRAGALACTIC JETS BY INTENSE LONG-WAVELENGTH ELECTROMAGNETIC-FIELDS

Many quasars and active galactic nuclei (AGN) appear in radio maps (an d also in some cases in the optical and X-ray) as a bright nuclear sou rces from which emerge single or double long thin jets. When observed with high angular resolution these jets show structure with bright kno ts separated by relatively dark regions (Bridle & Eilek 1984; Thomson et al. 1993a). High percentages of polarization are observed, sometime s more than 50%, which is well explained as the synchrotron radiation of the relativistic electrons in a weak but ordered magnetic fields. E stimation of the life time of these electrons, based on the observed l uminosities and spectra, often gives values much less than their kinem atic ages d/c, where d is the distance of the emitting point from the central source. Because the jet Row most likely originates from outbur sts or continuous outflow from the central source, one comes to the ne cessity of continuous re-acceleration of electrons or in situ accelera tion of electrons in the jets in order to explain the observations. He re, we propose that the time-dependent propagation of a relativistic j et leads to the formation of a boundary layer region filled with long- wavelength electromagnetic waves. In this region, charged particles ar e directly accelerated by the electric field of the waves.