Solar Prominence Bubbles and Associated Plasma Instabilities: IRIS Observations and MHD Modeling

Solar prominences are cool and dense plasma in the hot corona. The so-called prominence bubbles are mysterious, dome-shaped, apparently void structures residing in the lower portions of prominences. Such bubbles are associated with various plasma instabilities, such as the Rayleigh-Taylor (RT) and Kelvin-Helmholtz (KH) instabilities. The former is manifested in plumes that are often produced at the top boundary of a bubble and intrude upward into the dense prominence material. The latter is found to be triggered by shear flows at the bubble boundaries. We present recent observations of prominence bubbles by IRIS, focusing on the diagnostic potential of RT and KH instabilities on the physical conditions of the prominence and its supporting magnetic field. We search for evidence of magnetic flux emergence as the origin of prominence bubbles. We also present preliminary 3D MHD simulations of the interaction of a bipole, as a hypothetical bubble, emerging into an overlying prominence-carrying flux-rope system. The simulations can provide further clues to the origin and nature of prominence bubbles. We discuss their roll in mass ad magnetic flux transport in the solar atmosphere.