  We use measurements from the Rosetta plasma consortium (RPC) Langmuir probe
(LAP) and mutual impedance probe (MIP) to study the spatial distribution of
low-energy plasma in the near-nucleus coma of comet 67P/Churyumov-Gerasimenko.
The spatial distribution is highly structured with the highest density in the
summer hemisphere and above the region connecting the two main lobes of the
comet, i.e. the neck region. There is a clear correlation with the neutral
density and the plasma to neutral density ratio is found to be about 1-2x10^-6,
at a cometocentric distance of 10 km and at 3.1 AU from the sun. A clear 6.2 h
modulation of the plasma is seen as the neck is exposed twice per rotation. The
electron density of the collisonless plasma within 260 km from the nucleus
falls of with radial distance as about 1/r. The spatial structure indicates
that local ionization of neutral gas is the dominant source of low-energy
plasma around the comet.
