The connection of Type II Spicules to the Corona
  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. 
Philip G. Judge, Bart de Pontieu, Scott McIntosh, Kosovare Olluri
astro-ph.SR