  We present an electron projection imaging method to study the ultrafast
evolution of photoelectron density distribution and transient fields near the
surface. The dynamical profile of the photoelectrons from graphite reveals an
origin of a thermionic emission, followed by an adiabatic process leading to
electron acceleration and cooling before a freely expanding cloud is
established. The hot electron emission is found to couple with a surface charge
dipole layer formation, with a sheet density several orders of magnitude higher
than that of the vacuum emitted cloud.
