  Macrospicules are relatively large spicule-like formations found mainly over
the polar coronal holes when observing in the transition region spectral lines.
In this study, we took advantage of the two short series of observations in the
He II 304 \r{A} line obtained by the TESIS solar observatory with a cadence of
up to 3.5 s to study the dynamics of macrospicules in unprecedented detail. We
used a one-dimensional hydrodynamic method based on the assumption of their
axial symmetry and on a simple radiative transfer model to reconstruct the
evolution of the internal velocity field of 18 macrospicules from this dataset.
Besides the internal dynamics, we studied the motion of the apparent end points
of the same 18 macrospicules and found 15 of them to follow parabolic
trajectories with high precision which correspond closely to the obtained
velocity fields. We found that in a clear, unperturbed case these macrospicules
move with a constant deceleration inconsistent with a purely ballistic motion
and have roughly the same velocity along their entire axis, with the obtained
decelerations typically ranging from 160 to 230 m/s^2, and initial velocities
from 80 to 130 km/s. We also found a propagating acoustic wave for one of the
macrospicules and a clear linear correlation between the initial velocities of
the macrospicules and their decelerations, which indicates that they may be
driven by magneto-acoustic shocks. Finally, we inverted our previous method by
taking velocities from the parabolic fits to give rough estimates of the
percentage of mass lost by 12 of the macrospicules. We found that typically
from 10 to 30% of their observed mass fades out of the line (presumably being
heated to higher coronal temperatures) with three exceptions of 50% and one of
80%.
