Inhibition of turbulent transfer in self-gravitating flows below the Jeans
length
Astron. and Astrophys.,324,L21,1997
R. Grappin J. Léorat and S. Hulin
Abstract
Turbulent flows within clouds with Jeans numbers of order unity are observed in
the
interstellar medium. In the absence of self-gravitation, compressible turbulent
flows
steepen, form shocks, and hence dissipate rapidly. We show here that, for
wavelengths
immediately below the gravitational instability threshold, this nonlinear
steepening does
not occur, and dissipation is drastically reduced. This result might alleviate
somewhat the
problem of feeding the turbulence in marginally stable clouds (with Jeans number
slightly
below unity).