  A solar filament is a dense cool condensation that is supported and thermally
insulated by magnetic fields in the rarefied hot corona. Its evolution and
stability, leading to either an eruption or disappearance, depend on its
coupling with the surrounding hot corona through a thin transition region,
where the temperature steeply rises. However, the heating and dynamics of this
transition region remain elusive. We report extreme-ultraviolet observations of
quiescent filaments from the Solar Dynamics Observatory that reveal prominence
spicules propagating through the transition region of the filament-corona
system. These thin needle-like jet features are generated and heated to at
least 0.7 MK by turbulent motions of the material in the filament. We suggest
that the prominence spicules continuously channel the heated mass into the
corona and aid in the filament evaporation and decay. Our results shed light on
the turbulence-driven heating in magnetized condensations that are commonly
observed on the Sun and in the interstellar medium.
