Mass injection rates due to supernovae and cloud evaporation in starburst superwinds

We show that, for reasonable assumptions, conductively driven and ablation-driven evaporation of clouds in the core of the starburst galaxy M82 lead to a rate of mass injection into the superwind that is several times greater than that due to supernovae. This is in harmony with the results of efforts to construct a global superwind model consistent with the X-ray emission of M82. We examine the possibility that the increase of pressure in a starburst causes the burst to develop by inducing gravitational instability of the clouds.