Electrostatic triple root structures: connections to supersolitons, double layers, and acoustic speed solitons in nonthermal plasmas with negative and positive dust
Abstract
Large-amplitude dust-acoustic solitons and double layers in a dusty plasma model comprised of
nonthermal Cairns electrons and ions, and cold, negative and positive dust grains had earlier been
investigated, before newer concepts such as supersolitons, solitons at the acoustic speed, and even
acoustic speed supersolitons arose. It turned out that under certain conditions, three distinct roots of
the same polarity coalesce into a triple root, so that now a systematic investigation is carried out
into the existence domains and properties of triple root solitary structures. From the analysis of the
Sagdeev pseudopotentials, it transpires that there is a wide range of compositional parameters and
soliton speeds where triple root structures can exist, and these are shown to be intimately connected
with double layer and supersoliton ranges. Thus, triple roots are much more common than at first
expected, even at the acoustic speed or in the presence of Boltzmann rather than Cairns nonthermal
hot species. Once the existence domains are properly established, as many examples can be worked
out as one chooses, generating typical soliton or double layer and electric field profiles. A great
many combinations of compositional parameters and soliton speeds have been numerically tested,
and they all reveal a similar pattern, with quantitative but no inherent qualitative changes
URI
http://hdl.handle.net/10394/26264https://doi.org/10.1063/1.5006026
http://aip.scitation.org/doi/pdf/10.1063/1.5006026