Sonoluminescence in granular media

Powder agglomeration patterns at acoustic driving observed by sonoluminescence technique

“…͑1͒ is based on a simple caricature of the effects accompanying an oscillating driving by incorporating both the theoretical pressure on grains and the experimental emission intensity as a function of applied pressure. 15 We therefore believe that the physics we have included in our model is sufficiently complete to roughly describe dynamics of grain particles undergoing SL. However, this approach is nontrivial to accurately implement various components which might govern the occurrence of SL such as driven-induced particle alignment effects together with a space distribution of the emission from a grain, heating of grain surfaces by the driving, etc.…”

“…An illuminating surface was characterized by spatially distributed luminescence spots that were imaged to produce two-dimensional snapshots of the surface color. 15 The surface color is a measure of the interparticle interactions, and this is a prerequisite for studying the dynamics of powder particles. In this way, the driven-induced evolution of powder arrangements could be serially monitored by imaging the evolution of arbitrary cross sections through the interior of a powder pattern.…”

“…It has been suggested already previously that the enhanced emissions come from the regions of increased packing densities of grains. 15 As a test of this suggestion, a few distinct experiments have been performed starting from less packed and more packed initial conditions. Figure 5͑a͒ shows the surfaceintegrated SL intensity as a function of U, using less packed ͑open circles͒ and more packed ͑closed circles͒ starting powders.…”

“…15 In this model, the occurrence of SL is treated in the framework of a simplified molecular kinetic approach for particle motions driven by a LiNbO 3 plate such that the intensity I of SL is presumed to be related to the average velocity v of a powder particle near the driving plate and the average spacing between nearest grains ln Iϰ͑2…”

Acoustically driven emission of light in granular and layered semiconductors: recent advances and future prospects

“…Hence, there is no reason to believe that the mixture of ZnS grains remains homogeneous. (Korotchenkov and Goto 1997). Using a driving voltage of U ≈ 70 V, the total radiance is roughly 10 −13 W and 0.2×10 −13 W in doped and undoped mixtures, respectively.…”