Kinetic roughening in slow combustion of paper - art. no. 036101

Results of experiments on the dynamics and kinetic roughening of one-dimens ional slow-combustion fronts in three grades of paper are reported. Extensi ve averaging of the data allows a detailed analysis of the spatial and temp oral development of the interface fluctuations. The asymptotic scaling prop erties, on long length and time scales, are well described by the Kardar-Pa risi-Zhang (KPZ) equation with short-range, uncorrelated noise. To obtain a more detailed picture of the strong-coupling fixed point, characteristic o f the KPZ universality class, universal amplitude ratios, and the universal coupling constant are computed from the data and found to be in good agree ment with theory. Below the spatial and temporal scales at which a crossove r takes place to the standard KPZ behavior, the fronts display higher appar ent exponents and apparent multiscaling. In this regime the interface veloc ities are spatially and temporally correlated, and the distribution of the magnitudes of the effective noise has a power-law tail. The relation of the observed short-range behavior and the noise as determined from the local v elocity fluctuations is discussed.