J. A. Linker, M. G. Kivelson, R. J. Walker, G eophys. F. M. Neubauer, J Geophys. C. K. Goertz, J. Geophys. We use the term ionization to include impact ionization and photo-ionization. Pickup refers to both ionization and charge exchange.
Ionization changes the plasma density.
Charge exchange changes the energy and mo- mentum of an ion in the plasma but, for like species, does not change the ion density. W. H. Smyth and M. R. Combi, J. Geophys. D. J. Southwood and M. W. Dunlop, Planet. The terms heating and cooling in this context refer to the change of the second moment of the distribution function when ions are introduced into the distribution. In this sense, ions added with perpendicular speeds above the thermal speed heat the plasma.