Variable charge dust acoustic solitary waves in a dusty plasma with a q-nonextensive electron velocity distribution

A first theoretical work is presented to study variable charge dust acoustic solitons within the theoretical framework of the Tsallis statistical mechanics. Our results reveal that the spatial patterns of the variable charge solitary wave are significantly modified by electron nonextensive effects. In particular, it may be noted that for -1 < q < 1 (where q stands for the electron nonextensive parameter) the soliton pulse amplitude increases while its width is narrowed as q -> 1. As the electrons deviate from their thermodynamic equilibrium, the dust grain charge Q(d) becomes more negative and the dust grains localization (accumulation) less pronounced. The electrons are locally expelled and pushed out of the region of the soliton's localization. This electron depletion becomes less effective as the electrons evolve far away from their thermal equilibrium. The case q > 1 provides qualitatively opposite results: electron nonextensivity makes the solitary structure more spiky. Our results should help in providing a good fit between theoretical and experimental results. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3428538]