  We investigate the properties of highly compressible turbulence and its
ability to produce self-gravitating structures. The compressibility is
parameterized by an effective polytropic exponent gama-eff. In the limit of
small gama-eff, the density jump at shocks is shown to be of the order of
e^{M^2}, and the production of vorticity by the nonlinear terms appears to be
negligible. In the presence of self-gravity, we suggest that turbulence can
produce bound structures for gama-eff < 2(1-1/n), where 'n' is the typical
dimensionality of the turbulent compressions. We show, by means of numerical
simulations, that, for sufficiently small gama-eff, small-scale turbulent
density fluctuations eventually collapse even though the medium is globally
stable. This result is preserved in the presence of a magnetic field for
supercritical mass-to-flux ratios.
