title: Nonlocal dynamics of spontaneous imbibition fronts.
abstract: We have studied spontaneous imbibition fronts generated by capillary rise between two roughened glass plates, the separation d of which varied between 10 and 50 microm. Perfect agreement with Washburn's law was obtained. We have determined the roughness exponent chi of the fronts, and found chi=0.81+/-0.01 for small length scales. Above a certain crossover length xi, it reached chi=0.58+/-0.04, as predicted by the quenched noise Kardar-Parisi-Zhang equation. The crossover length is found to scale with the plate separation as sqrt[d], as predicted by recent models which properly include nonlocal dynamics effects on the front. We believe this to be the first clear identification of crossover from nonlocal to local dynamics.
authors.affiliation: Applied Physics Lab, Ulm University, Germany. Dimitrios.Geromichalos@physik.uni-ulm.de
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Geromichalos
authors.forename: Frieder
authors.initials: F
authors.lastname: Mugele
authors.forename: Stephan
authors.initials: S
authors.lastname: Herminghaus