Large-Scale Instability in Giant Molecular Clouds

Appearance of the large-scale instability in the magnetized slightly-ionized gas in the Giant Molecular Clouds is discussed. Cloud gas is characterized by the fully developed small-scale magnetohydrodynamic helical turbulence. The instability analysis shows that the large-scale eddy coherent structures may be generated in the Giant Molecular Clouds. Characteristic scale of these structures is determined by the value of the hydrodynamic helicity as well as joint influence of the drag force and magnetic helicity. This revised version was published online in July 2006 with corrections to the Cover Date.