INHIBITION OF TURBULENT TRANSFER IN SELF-GRAVITATING FLOWS BELOW THE JEANS LENGTH

Turbulent flows within clouds with Jeans numbers of order unity are ob served in the interstellar medium. In the absence of self-gravitation, compressible turbulent flows steepen, form shocks, and hence dissipat e rapidly. We show here that, for wavelengths immediately below the gr avitational instability threshold, this nonlinear steepening does not occur, and dissipation is drastically reduced. This result might allev iate somewhat the problem of feeding the turbulence in marginally stab le clouds (with Jeans number slightly below unity).