Photon Bubbles in a Self-gravitating Dust Gas: Collective Dust Interactions

We consider broadband radiation interacting with a gas of self-gravitating dust grains. We show that photon-bubble formation can occur, due to a modified Jeans instability, which will imply the formation of two different kinds of dust density perturbations. This could be useful for understanding the B-mode signal observed in the CMB polarization survey, and other astrophysical processes, such as the formation of protoplanets and voids in dust clouds.