  Thanks to a Multiple Scattering Theory algorithm, we present a way to focus
energy at the deep subwavelength scale, from the far-field, inside a cubic
disordered bubble cloud by using broadband Time Reversal (TR). We show that the
analytical calculation of an effective wavenumber performing the Independant
Scattering Approximation (ISA) matches the numerical results for the focal
extension. Subwavelength focusings of lambda/100 are reported for simulations
with perfect bubbles (no loss). A more realistic case, with viscous and thermal
losses, allows us to obtain a $\lambda/14$ focal spot, with a low volume
fraction of scatterers (phi = 0.01). Bubbly materials could open new
perspective for acoustic actuation in the microfluidic context.
