  The paper presents an integrated view of the population structure and its
role in establishing the ionisation state of light elements in dynamic, finite
density, laboratory and astrophysical plasmas. There are four main issues, the
generalised collisional-radiative picture for metastables in dynamic plasmas
with Maxwellian free electrons and its particularising to light elements, the
methods of bundling and projection for manipulating the population equations,
the systematic production/use of state selective fundamental collision data in
the metastable resolved picture to all levels for collisonal-radiative
modelling and the delivery of appropriate derived coefficients for experiment
analysis. The ions of carbon, oxygen and neon are used in illustration. The
practical implementation of the methods described here is part of the ADAS
Project.
