A “wave automaton” for wave propagation in the time domain: II. Random systems

Patrick Sebbah , Didier Sornette , Christian Vanneste

Following our previous description of the “wave automaton”, a new lattice model introduced for the dynamical propagation of waves in arbitrary heterogeneous media which is efficient for calculations on large systems (1024 ×1024) over long times (several 106 inverse band widths), we present a detailed study of the time-dependent transport of wave packets in 2D-random systems. The scattering of a Bloch wave in a periodic system by a single impurity is first calculated analytically, which allows us to derive the elastic mean free time τ. and mean free length ℓe as a function of the model parameters and the frequency f = ω/2 π. We then expose the different results on wave packets in random media which have been obtained using extensive numerical simulations on a parallel computer. We study the different regimes (ballistic, diffusive, localized) which appear as the wave packets spread over the random media and compare these numerical results with weak localization predictions.

Domaines: Articles anciens

Patrick Sebbah, Didier Sornette, Christian Vanneste. A “wave automaton” for wave propagation in the time domain: II. Random systems. Journal de Physique I, 1993, 3 (6), pp.1281-1302. ⟨10.1051/jp1:1993155⟩. ⟨jpa-00246797⟩