The Shock Front Rise Time in Water.

A review is made of the present status of the experimental-theoretical program for the evaluation of the shock front thickness in water, and the results of recently performed hyperbolic tangent shock front structure calculations are presented. The hyperbolic tangent results, when compared with experimental data, predict a shock front thickness upper limit of 6.2 X 10 to the minus 6th power cm at 5.8 kbar. Experiments and theory planned for the near future are outlined. These experiments will involve shock front optical reflectivity and shock polarization voltage measurements. Some preliminary theory corresponding to these planned experiments is presented. In particular, a net electric dipole alignment calculation is presented which predicts approximately 5 mv across a 50-ohm load at 15 kbars. The anomalously large Soviet shock viscosity results are considered (without resolution of the question), and the possibility of significant hydrogen bond breaking at shock pressures above 5.8 kbars is discussed.