Reversible propagating fingers in an antiferroelectric liquid crystal

Propagating fingerlike solitary waves are observed in an antiferroelectric liquid crystal on application of an electric field above a threshold field ${\mathit{E}}_{\mathrm{th}}$. On reducing the field below ${\mathit{E}}_{\mathrm{th}}$ the fingers recede, also as solitary waves. The velocity of the waves, which to our knowledge is the fastest observed for a liquid crystal, scales approximately as E-${\mathit{E}}_{\mathrm{th}}$ for E near ${\mathit{E}}_{\mathrm{th}}$. A simple model, which includes a layer-layer coupling term, is presented and describes much of the observed behavior.