Cnoidal waves and solitons for coupled drift and ion acoustic waves in shear flow oxygen-hydrogen plasma of upper ionosphere

Abstract Nonlinear periodic (cnoidal) wave structures developed by the coupled drift wave (DW) and ion acoustic waves (IAWs) are studied in a magnetized inhomogeneous collisionless bi-ion plasma with ions shear flow along the ambient magnetic field <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>B</mml:mi> <mml:mo>=</mml:mo> <mml:msub> <mml:mrow> <mml:mi>B</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> </mml:msub> <mml:mover accent="true"> <mml:mrow> <mml:mi>z</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>ˆ</mml:mo> </mml:mrow> </mml:mover> </mml:math> . The electrons are assumed to follow κ -distribution in which κ is an indicator of the superthermal character of the electrons. A nonlinear differential equation like Korteweg–de Vries (KdV) equation is derived by introducing a co-moving frame transformation. It is found that the nonlinearity present in the plasma system forms rarefactive drift acoustic wave pulses whose amplitude and width depends on plasma parameters such as shear flow, superthermality and density inhomogeneity. The most significant contribution of the present investigation is the illustrations of the impacts of variation of density inhomogeneity on cnoidal and solitary structure profiles of pure drift mode. The results are compiled on the basis of plasma data available from Freja experimental observations in the upper ionosphere.