Models of wave supported clumps in giant molecular clouds

We present plane-parallel equilibrium models of molecular clumps that are supported by Alfvén waves damped by the linear process of ion-neutral friction. We used a WKB approximation to treat the inward propagation of waves and adopted a realistic ionization structure influenced by dissociation and ionization due to photons of external origin. The model clumps contain central condensations surrounded by lower density envelopes and are more condensed than those obtained for an assumed ionization structure, used in some previous studies, that is more appropriate for dark regions. In some parameter regimes the structures of clumps depend sensitively on the assumed depletions of Sulphur and metals.