  We examine the hypothesis that plasma associated with "Type II" spicules is
heated to coronal temperatures, and that the upward moving hot plasma
constitutes a significant mass supply to the solar corona. 1D hydrodynamical
models including time- dependent ionization are brought to bear on the problem.
These calculations indicate that heating of field-aligned spicule flows should
produce significant differential Doppler shifts between emission lines formed
in the chromosphere, transition region, and corona. At present, observational
evidence for the computed 60-90 km/s differential shifts is weak, but the data
are limited by difficulties in comparing the proper motion of Type- II
spicules, with spectral and kinematic properties of associated transition
region and coronal emission lines. Future observations with the upcoming IRIS
instrument should clarify if Doppler shifts are consistent with the dynamics
modeled here.
