EXTENDED STATES OF NONLINEAR TRAVELING-WAVE CONVECTION .2. FRONTS AND SPATIOTEMPORAL DEFECTS

This paper continues a description of experiments on one-dimensional, nonlinear, traveling-wave convection in a binary fluid with separation ratio psi = -0.127 in a narrow annular cell. It is possible to create and manipulate steady-state sources and sinks of traveling waves in this system, as well as to produce stable fronts that separate convecting and quiescent regions. Source defects tend to drift at constant velocity, emitting Doppler-shifted traveling waves whose wave number lies outside the Eckhaus boundary measured for spatially uniform traveling-wave states. I present both qualitative descriptions of such phenomena and quantitative measurements of the amplitude and wave-number profiles of sources, sinks, and fronts.