Mechanism of Radiation Acceleration for JET IN SS433

The 'knotty' structure is a common feature of many astrophysical jets and outflows. In this work the process of an individual 'bullet' acceleration under influence of the radiation pressure is investigated. The 'bullet' is placed inside a cylindrical funnel above a hot central object. Results show that a powerful acceleration of the bullet takes place in most of physically possible sets of parameters. The bullet is accelerated under influence of radiation pressure inside funnel up to sublight velocities. The other important feature of our results is that the main acceleration performed during very short distance - about 1 - 2 diameters of the bullet. So, very long funnels are not necessary for bullet's acceleration up to sublight velocities and such processes could take place inside accretion funnels of thick disks around black holes.