Accretion and Particle Acceleration by Spiral Shock Waves

Abstract

The physics of accretion through a system of stationary spiral shaped shock waves is reviewed. The angular momentum transport by such waves can be described in terms of the negative angular momentum carried by trailing waves. Excitation processes are discussed. In ‘large’ disks (inner radius r i <<< outer radius r o ) there is a range of distances r i << r << r o where the shock-accretion solution is insensitive to conditions at both r i and r o . For a simple equation of state and opacity this part of the solution has a selfsimilar (scale invariant) form. These properties make spiral shocked accretion especially attractive in protostellar, neutron star and AGN disks, where the traditional ‘angular momentum problem’ is most severe. It is shown that spiral shocks are also good locations for producing energetic protons, and I propose that this is the way in which the energetic particles inferred in many AGN’s are produced.