  We propose a mechanism by which the efficiency of mixing in chaotic flows can
be enhanced. Our mechanism consists of introducing small changes in the system
parameters in regions of phase space where the local Lyapunov exponent falls
substantially below its average value. We have applied our mechanism to several
typical chaotic maps and flows including a system of chemical reactions. We
find that our method is quite efficient as it gives a substantial enhancement
of the rate of mixing with small changes in system parameters, without
disturbing the attractor significantly.
