Preprint A333/2004
Complete time-reversed refocusing in reflection with an acoustic lagrangian model

Andre Nachbin | Alfaro, Daniel | Correia, Adolfo

**Keywords: **
Scattering of acoustic waves | acoustic time-reversal | Numerical schemes

This work presents discrete reflection-transmission
acoustic models through which numerical experiments are performed
efficiently. Each model is expressed through its
corresponding reflection-transmission matrix and
their connections with the continuous acoustic
model are discussed in detail. Important physical phenomena
are studied computationally.
In particular reflection-transmission
properties of waves in a rapidly varying random medim, which are
valid over long propagation distances.
By using a long computational domain, in a regime where
we have Anderson localization, the energy of an incoherently scattered
signal is entirely reflected back and, by time-reversal, completely
recompressed into the smooth initial data.
Another new result is the time-reversed refocusing, in reflection,
of a wave train in the form of a bit stream. The robustness of the time-reversed
refocusing phenomenon is outstanding.