Radiation acceleration of matter in accretion funnels associated with astrophysical objects

An axially symmetrical channel (or expanding funnel) can form during the ac cretion of matter onto a massive object. The base of this structure should be a powerful source of photons. The possibility of Radiation Acceleration of individual clumps of matter in such a funnel is examined. The radiationa l-acceleration model adopted is based on the concepts of geometrical optics . It is demonstrated that there can be efficient acceleration to a limiting velocity in such a system. This limiting velocity is determined by a numbe r of properties of the system, including the temperatures and reflection co efficients of the central source, channel wall, and accelerated object; it can reach a substantial fraction of the speed of light. This velocity appre ciably exceeds the velocity that can be reached during the acceleration of a body above a central source of the same luminosity without a surrounding channel wall that reflects photons back into the accretion funnel. The main acceleration occurs over a short distance of the order of two to three tim es the channel diameter. The model takes into account the gravitational of the central body and the finite optical depth of the accelerated object. Th e influence of the shape of the channel and of the relativistic reddening o f photons on the limiting velocity is considered. Application of the model to astrophysical objects such as SS 433 is discussed.