Bimodal ion energy distribution functions in a hydrogen magnetized plasma

Direct measurements of temporal evolution of the ion energy distribution functions (IEDFs) in a pulsed magnetized hydrogen plasma with a complex spatial structure are presented. The results show a remarkable split of the curves into two peaks of energy that draw away as the spatial structure expands until they reach a complete separation. The behavior is explained in terms of E x B drift velocity plasma dynamics and its influence on the IEDFs, with consequences for ion temperature measurements. The development of a criterion to calculate the ion temperatures allows us to obtain the temporal evolution of this parameter for the three ion species, H+, H-2(+) and H-3(+).