Shock Waves in the Large-Scale Structure of the Universe
  Cosmological shock waves are induced during hierarchical formation of large-scale structure in the universe. Like most astrophysical shocks, they are collisionless, since they form in the tenuous intergalactic medium through electromagnetic viscosities. The gravitational energy released during structure formation is transferred by these shocks to the intergalactic gas as heat, cosmic-rays, turbulence, and magnetic fields. Here we briefly describe the properties and consequences of the shock waves in the context of the large-scale structure of the universe. 
Dongsu Ryu (Chungnam National University, Korea) and Hyesung Kang   (Pusan National University, Korea),