  In this paper we present a numerical study of the dynamics of partially
ionized coronal rain blobs. We use a two-fluid model to perform a
high-resolution 2D simulation that takes into account the collisional
interaction between the charged and neutral particles contained in the plasma.
We follow the evolution of a cold plasma condensation as it falls through an
isothermal vertically stratified atmosphere that represents the much hotter and
lighter solar corona. We study the consequences of the different degrees of
collisional coupling that are present in the system. On the one hand, we find
that at the dense core of the blob there is a very strong coupling and the
charged and neutral components of the plasma behave as a single fluid, with
negligible drift velocities (of a few cm s^-1). On the other hand, at the edges
of the blob the coupling is much weaker and larger drift velocities (of the
order of 1 km s^-1) appear. In addition, frictional heating causes large
increases of temperature at the transition layers between the blob and the
corona. For the first time we show that such large drift velocities and
temperature enhancements can develop as a consequence of ion-neutral decoupling
associated to coronal rain dynamics. This can lead to enhanced emission coming
from the plasma at the coronal rain-corona boundary, which possesses transition
region temperature.
