In this article, a model which examines the evolution of ion concentrations
in a hot aircraft exhaust plume on the ground is proposed. The model inclu
des plume dilution and ion-ion recombination with coefficients which vary w
ith temperature. A comparison of the model is made with the available groun
d-based experimental data obtained on the ATTAS research aircraft engines.
From this comparison, an ion emission index of the order of 8 10(16) ions/k
g(fuel) is inferred.