Ion current calculation in a system of plane grids in an ionised gas flow

A method for a unidimensional space charge calculation in an ionised gas flow is described. Different ion species of different mobilities are present in the gas. The authors use analytical expressions for both space and potential versus local electric field. They apply this calculation to the space between plane parallel grids whose transparencies are computed from a model previously described. They compare results with an experiment made in ambient air and a good fit is found by assuming that only two ion species are present in the gas flow.