Two types of lower-hybrid waves in dusty plasmas and cusp solitons

Abstract

A theoretical model is presented for the excitation of ultralow frequency dust-lower hybrid mode DLH oscillating at frequency lhd= Zdndo /nio ci cd by employing the decay of a relatively high frequency dust-modified lower-hybrid DMLH wave into a relatively lower frequency DMLH and DLH based on three-wave resonant interaction. A coupled nonlinear Schrödinger NLS equation for the DMLH wave and Zakharov equation for the DLH wave are derived. The nonlinear contribution in the NLS equation comes from the DLH density fluctuations. Modulational instabilities of DMLH waves are investigated and its growth rates are studied. Additionally, one-dimensional nonlinear localized structures of bright solitons and nonlinear nonlocal structures like cusp solitons are obtained. It is shown that, when the phase velocity resonates with the dust sound speed / vo , the nonlocal nonlinearity leads to the generation of cusp solitons