Collisionless shocks are a common astrophysical phenomenon associated with energetic sources in the Universe. There are many poorly understood physical processes associated with collisionless shocks, but one important property of collisionless shocks is their ability to accelerate particles to very high energies. The process is likely diffusive shock acceleration, and there are various open questions regarding this process: how are particles injected in the process, what is the efficiency of the process, and what is the role of magnetic fields?
Diffusive acceleration appears to occur in shocks of various length scales and from very different energy sources: on (sub)AU scales in the solar system, on parsec scales in supernova remnants, and on megaparsec scales in clusters of galaxies.
The study of these various shocks takes place in different communities, who all have their own tools to probe shock acceleration properties. In addition collisionless shocks are investigated through numerical simulations and in the laboratory. The aim of this workshop is to bring key people from these communities together in order to discuss what these various shocks have in common, in what sense they are different, and what the variation in properties means for the process of diffusive shock acceleration in general.