Astron. Astrophys. 324, L21-L24 (1997)

1. Introduction

The interstellar matter in molecular clouds shows a quasi-steady turbulent state (Larson, 1981, Falgarone and Pérault 1987). Feeding this turbulence is a problem, in view of the rapid energy dissipation of compressible flows in shocks (Shu et al 1987). Magnetic fields could possibly reduce the energy requirement by reducing the dissipation rate (Kraichnan 1967). In this letter, we indicate another possible solution valid in the framework of hydrodynamics, by showing that spectral transfer and dissipation of waves with wavelength near the instability threshold are reduced or even stopped by the dispersive effect of self-gravitation. We show this by phenomenological arguments as well as by numerical simulations. We finally discuss the applicability of this result to interstellar clouds.

© European Southern Observatory (ESO) 1997

Online publication: May 26, 1998

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