  A new model for the interaction of an electric pulse with a lipid membrane is
proposed. Using this model we show that when a DC electric pulse is applied to
an insulating lipid membrane separating fluids with different conductivities,
the capacitive charging current through the membrane drives electrohydrodynamic
flow that destabilizes the membrane. The instability is transient and decays as
the membrane charges. The bulk conductivity mismatch plays an essential role in
this instability because it results in a different rate of charge accumulation
on the membrane's physical surfaces. Shearing stresses created by the electric
field acting on its own induced free charge are non-zero as long as the charge
imbalance exists. Accordingly, the most unstable mode is related to the ratio
of membrane charging time and the electrohydrodynamic time.
