Wave propagation in strongly scattered random elastic media: Energy equilibration and crossover from ballistic to diffusive behavior

Ying Wu*, Yun Lai, Yanyi Wan, Zhao Qing Zhang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

We studied the energy equilibration process of elastic wave propagation through a strong-scattering random medium via multiple-scattering theory and the radiative transfer equation. The equilibration of the shear and compressional energy densities due to the mode conversions is clearly observed in both calculations, although the ratio of the shear energy density to the compressional energy density obtained from the multiple-scattering theory is higher than that obtained from the radiative transfer equation, which has the value predicted by the principle of the equipartition of wave modes. The discrepancy is due to the presence of a negative interference energy inside the sample. This is in contrast to the common belief that the interference energy density of a weak-scattering random medium always averages to zero inside the medium except near its boundaries. We also showed that the negative interference energy is concentrated near the boundary of each scatterer and, therefore, cannot be averaged to zero. In addition, we studied various distribution functions of the transmitted waves in thin samples before the establishment of the energy equilibration. We found that these distribution functions are described well by a random-phasor-sum model and they exhibit crossover behavior from ballistic to diffusive transport.

Original languageEnglish (US)
Article number125125
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume77
Issue number12
DOIs
StatePublished - Mar 17 2008

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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