Intensity Oscillations in the upper transition region above active region plage

Although there are now many observations showing the presence of oscillations in the corona, almost no observational studies have focused on the bright upper transition region (TR) emission (so-called moss) above active region plage. Here we report on a wavelet analysis of observations (made with TRACE, the Transition Region and Coronal Explorer) of strong ( ∼ 5-15%) intensity oscillations in the upper TR footpoints of hot coronal loops. They show a range of periods from 200 to 600 seconds, typically persisting for 4 to 7 cycles. These oscillations are not associated with sunspots, as they usually occur at the periphery of plage regions. A majority of the upper TR oscillations are directly associated with upper chromospheric oscillations observed in Hα , i.e., periodic flows in spicular structures. The presence of such strong oscillations at low heights (of order 3,000 km) provides an ideal opportunity to study the propagation of oscillations from photosphere and chromosphere into the TR and corona, and improve our understanding of the magnetic connectivity in the chromosphere and TR. In addition, we use new high resolution observations of the photosphere and chromosphere, taken with the Swedish Solar Telescope, to shed light on the source of chromospheric mass flows such as spicules.