Speaker
Paul Bryans
Description
IRIS provides an unparalleled opportunity to explore the (thermal)
interface between the chromosphere, transition region, and the coronal
plasma observed by AIA. The SDO/AIA observations of a coronal loop
footpoint show strong recurring upward propagating signals - "propagating
coronal disturbances'' (PCDs) with apparent speeds of order 120 km/s. That
signal has a clear signature in the slit-jaw images of IRIS in addition to
identifiable spectral signatures and diagnostics in the Mg II h line. In
analyzing this line, we are able to observe the presence of magnetoacoustic
shock waves that are also present in the vicinity of the coronal loop
footpoints. We see there is enough of a correspondence between the shock
propagation in Mg II h, the evolution of the Si IV line profiles, and the
PCD evolution to indicate that these waves are also an important ingredient
for PCDs such that waves and flows both appear to be contributing to the
signals observed.
