  Kinetic exospheric models revealed that the solar wind is accelerated by an
ambipolar electric field up to supersonic velocities. The presence of
suprathermal Strahl electrons at the exobase can further increase the velocity
to higher values, leading to profiles comparable to the observations in the
fast and slow wind at all radial distances. Such suprathermal electrons are
observed at large distances and recently at low distances as well. Those
suprathermal electrons were introduced into the kinetic exospheric model using
Kappa distributions. Here, the importance of the exobase's altitude is also
underlined for its ability to maintain the electric potential to a higher level
for slower winds, conversely to what is induced through the effect of a lower
kappa index only. In fact, the exobase is located at lower altitude in the
coronal holes where the density is smaller than in the other regions of the
corona, allowing the wind originating from the holes to be accelerated from
lower distances to higher velocities. The new observations of Parker Solar
Probe (PSP) and Solar Orbiter (SolO) from launch to mid-2023 are here used to
determine the characteristics of the plasma in the corona so that the model
fits best to the averaged observed profiles for the slow and fast winds. The
observations at low radial distances show suprathermal electrons already well
present in the Strahl in the antisunward direction and a deficit in the sunward
direction, confirming the exospheric feature of almost no incoming particles.
