Optical probing of shocks driven into overdense plasmas by laser   hole-boring
  Observations of the interaction of an intense {\lambda}0 \approx 10 {\mu}m laser pulse with near-critical overdense plasmas (ne = 1.8 - 3 nc) are presented. For the first time, transverse optical probing is used to show a recession of the front surface caused by radiation pressure driven hole-boring by the laser pulse with an initial velocity > 10^6 ms-1, and the resulting collisionless shocks. The collisionless shock propagates through the plasma, dissipates into an ion-acoustic solitary wave, and eventually becomes collisional as it slows further. These conclusions are supported by PIC simulations which show that the initial evolution is dominated by collisionless mechanisms. 
N. P. Dover, C. A. J. Palmer, M. Babzien, A. R. Bell, A. E. Dangor, T.   Horbury, M. Ispiriyan, M. N. Polyanskiy, J. Schreib...
physics.plasm-ph