Dr Shimul Maharaj from SANSA  will present the NASSP seminar with a talk entitled, "Nonlinear potential structures in two-dust (or ion) plasmas".

Dr Maharaj will present theoretical results for plasma models with two heavy dust (or ion) constituents and electrons (and ions for plasmas with dust). The results will demonstrate how the sign of the charge on the dust grains affects the polarity of the supported nonlinear potential structures such as solitons and double layers. Solitons are symmetric (bell-shaped) structures in potential. Double layers, on the other hand, are asymmetric (ramp-like) potential structures. Additionally, I will discuss how stopbands can arise for fast mode solitons in certain restricted regions in parameter space. The stopband is an intermediate range of speeds for which fast mode solitons cannot propagate. On either side of the stopband are two passband regions where fast mode solitons can propagate