The modification by diffuse radiation of "cometary tail" formation behind globules

We study the evolution of a globule of neutral material immersed in the mor e tenuous hotter plasma of an H II region surrounding newly born OB stars. The neutral globule is illuminated by the direct ionizing radiation of OB s tars, and by diffuse radiation emitted by recombination in the surrounding ionized gas. W perform 2D, time dependent axisymmetric hydrodynamic simulat ions, and find that, for values of the diffuse field of the order of 10% of the direct field, the evolution of the globule is completely different to its evolution when the diffuse field is neglected.