  This work studies the kinematics of the leading edge and the core of 6
Coronal Mass Ejections (CMEs) in the combined field of view of Sun Watcher
using Active Pixel System detector and Image Processing (SWAP) on-board PRoject
for On-Board Autonomy (PROBA-2) and the ground-based K-Cor coronagraph of the
Mauna Loa Solar Observatory (MLSO). We report, for the first time, on the
existence of a critical height h$_\mathrm{c}$, which marks the onset of
velocity dispersion inside the CME. This height for the studied events lies
between 1.4-1.8 R$_{\odot}$, in the inner corona. We find the critical heights
to be relatively higher for gradual CMEs, as compared to impulsive ones,
indicating that the early initiation of these two classes might be different
physically. We find several interesting imprints of the velocity dispersion on
CME kinematics. The critical height is strongly correlated with the flux-rope
minor radius and the mass of the CME. Also, the magnitude of velocity
dispersion shows a reasonable positive correlation with the above two
parameters. We believe these results will advance our understanding of CME
initiation mechanisms and will help provide improved constraints to CME
initiation models.
