Experiments on grid-excited solitons in a positive-ion–negative-ion plasma

Experiments on the grid excitation and subsequent propagation of solitons in a positive-ion--negative-ion--electron plasma are described. In the experiments, the ratio of the negative-ion density to the positive-ion density in a quasineutral plasma is a parameter that can be varied. Hence solitons that are described by either the Korteweg--de Vries or the modified Korteweg--de Vries equations can be experimentally investigated.