Dynamics of nonlinear ion-acoustic waves in Venus’ lower ionosphere

Dynamics of nonlinear ion-acoustic waves (IAWs) are studied for Venus’ lower atmosphere at an altitude of $200-1000$ $200-1000$ km. Two-soliton, nonlinear solitary and periodic waves in a three-component plasma consisting of $H^{+}$ $H^{+}$ and $O^{+}$ $O^{+}$ ions with kappa distributed electrons are studied. Using the reductive perturbation technique (RPT), the Korteweg-de Vries (KdV) equation is derived and a Planar dynamical system is formed for the KdV equation using a travelling wave transformation. A phase portrait is drawn to analyze nonlinear wave behaviors by adjusting the parameters $\kappa$ $\kappa $ (spectral index), $\gamma$ $\gamma $ (unperturbed number density ratio), and $V$ $V$ (travelling wave speed). Increasing values of $\kappa$ $\kappa $ amplify amplitudes for solitary and periodic waves, narrow down the width of the solitary wave, and broaden the width of the periodic wave. Increasing value of $\gamma$ $\gamma $ boosts amplitude of the solitary wave with unchanged width, while amplitude of the nonlinear periodic wave decreases and width widens. Increasing value of $V$ $V$ enhances amplitudes and reduces widths for both solitary and periodic waves. Two-soliton solutions for the KdV equation are studied using the Hirota direct method. Increasing value of $\gamma$ $\gamma $ reduces amplitude of the soliton without affecting the width and increasing value of $\kappa$ $\kappa $ reduces width of the soliton. Phase shift for two-soliton is also shown and found that for different values of $\kappa$ $\kappa $ , the phase shift increases on increasing value of $\gamma$ $\gamma $ . The findings of our result aid in understanding the dynamics of nonlinear waves and two-soliton solutions in Venus’ lower ionosphere.