Multiscale nature of collisionless shocks

A collisionless shock possesses a well-developed structure with different scaler present. At the macroscale (much larger than the shock width) the usual Rankine-Hugoniot relations hold. The inhomogeneity occurs at the mesoscale (shock width) where ions are reflected and heated. The microscale (inside the ramp) magnetic and electric fields determine which ions are reflected and the electron dynamics. At the very large scales the Fermi-acceleration produces high energy particles which moderate the shock. The processes at different scales are interrelated, and a kind of a bootstrap can be expected. There is also some kind of the spectral energy transfer from the large scales to the small scales. This energy transfer is accompanied by the energy transfer into opposite direction - to accelerated particles.