Boundary-induced wavelength selection in a one-dimensional pattern-forming system.

We have measured the stability boundary for steady electroconvection in thin, freely suspended liquid crystal lms. As the voltage across the lm, or the lm length, is varied, convective vortices are created or destroyed at the ends of the lm to keep the pattern wave number within a stable range. The measured stability boundary lies substantially inside the Eckhaus boundary calculated for this system. Our results are consistent with a mechanism for boundary-induced wavelength selection proposed by Cross et al. [Phys. Rev.