Complex behaviour of spiral waves induced by an alternating electric field.

An efficient control of chemical waves is desirable in various fields of science and engineering. We present a novel method to control the motion of the spiral tip using an electric field perpendicular to the plane of wave propagation. An alternating field may lead to complex spatio-temporal patterns. Shown in the picture is an example of the destabilising effect of an alternating electric field, in which the wavefront displays fluctuating wrinkles.