Propagating front in an excited granular layer
Propagating front in an excited granular layer
A partial monolayer of $\ensuremath{\sim}20000$ uniform spherical steel beads, vibrated vertically on a flat plate, shows remarkable ordering transitions and cooperative behavior just below 1g maximum acceleration. We study the stability of a quiescent disordered or ``amorphous'' state formed when the acceleration is switched off in the excited ``gaseous'' state. …