Dynamics of the Free Surface of a Conducting Liquid in a Near-Critical   Electric Field
  Near-critical behavior of the free surface of an ideally conducting liquid in an external electric field is considered. Based on an analysis of three-wave processes using the method of integral estimations, sufficient criteria for hard instability of a planar surface are formulated. It is shown that the higher-order nonlinearities do not saturate the instability, for which reason the growth of disturbances has an explosive character. 
N. M. Zubarev and O. V. Zubareva