MASS-LOADED ASTRONOMICAL FLOWS .5. TAILS - INTERMEDIATE-SCALE STRUCTURES IN FLOWING CLUMPY MEDIA

The interactions between diffuse flowing plasmas and embedded clumpy material are important for the global structure and evolution of many flows of astronomical significance. The nature of the interactions is controlled by processes which occur in thin boundary layers. On intermediate scales, the relative motion of the global flow and the clumps produces extended structures - tails. We examine with simple models various interaction processes which lead to tail formation, and argue that long narrow tails are formed only if the diffuse flow and the mass injection into this flow take place subsonically. We discuss some examples of observed tails in the light of adopted phenomenological models.