Very High Mach Number Electrostatic Shocks in Collisionless Plasmas
  The kinetic theory of collisionless electrostatic shocks resulting from the collision of plasma slabs with different temperatures and densities is presented. The theoretical results are confirmed by self-consistent particle-in-cell simulations, revealing the formation and stable propagation of electrostatic shocks with very high Mach numbers ($M \gg 10$), well above the predictions of the classical theories for electrostatic shocks. 
G. Sorasio, M. Marti, R. Fonseca, L. O. Silva