We investigate the existence of ion-acoustic shock waves in a five component cometary plasma consisting of positively and negatively charged oxygen ions, kappa described hydrogen ions, hot solar electrons, and slightly colder cometary electrons. The KdVB equation has been derived for the system, and its solution plotted for different kappa values, oxygen ion densities, as well as the temperature ratios for the ions. It is found that the amplitude of the shock wave decreases with increasing kappa values. The strength of the shock profile decreases with increasing temperatures of the positively charged oxygen ions and densities of negatively charged oxygen ions.

We investigate the existence of compressive and rarefactive solitary waves in a five-component plasma. Positively and negatively multiply charged heavier ions (dust), kappa function described photo-electrons, hot electrons and ions form the five components. The pseudo-potential approach is used to determine the existence of a soliton. We find that the Sagdeev potential as well as the amplitude of the solitary wave for both compressive and rarefactive solitons increases with increasing spectral indices of the kappa distributions describing the cometary species. The magnitude of the amplitude of the solitary wave increases with increasing positively charged ion densities and charge numbers, but decreases with increasing charge numbers of the negative ions for both type of solitons.

We have, in this paper, studied the stability of the ion-acoustic wave in a plasma composed of hydrogen, positively and negatively charged oxygen ions, and electrons, which approximates very well the plasma environment around a comet. Modelling each cometary component (H+, O+, and O−) by a ring distribution, we find that ion-acoustic waves can be generated at frequencies comparable to the hydrogen ion plasma frequency. The dispersion relation has been solved both analytically and numerically. We find that the ratio of the ring speed (u⊥s) to the thermal spread (vts) modifies the dispersion characteristics of the ion-acoustic wave. The contrasting behaviour of the phase velocity of the ion-acoustic wave in the presence of O− ions for u⊥s>vts (and vice versa) can be used to detect the presence of negatively charged oxygen ions and also their thermalization.

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We investigate the existence of Ion-Acoustic solitary/shock waves in a five component cometary plasma consisting of positively and negatively charged oxygen ions, kappa described hydrogen ions, hot electrons and cold electrons. The KPB equation is derived for the system; its solution is plotted for different kappa values, as well as for the temperature ratios of ions. It is found that the amplitude of solitary structure increases with increasing kappa values and negatively charged oxygen ion densities. As the temperature of the positively charged oxygen ions increases, the amplitude of solitary wave also increases. We have also studied the dependence of coefficients of the KPB equation on physical parameters relevant to comet Halley.

Multicomponent plasma in an astrophysical environment comprising wind electrons, cometary electrons, positive and negative dust ions, and lighter hydrogen ions was studied earlier by a pseudo-potential approach. The coma of comet Halley is reported to comprise many heavier positive and negative ions. Thus, we generalize the soliton solution for a plasma consisting of multiple pair-ion dust species. Heavier atomic and molecular ions are considered as dust ions in this model. The lighter ions and electrons are modeled by Kappa distribution. We find that the presence of multiple dust pair ions enhances soliton amplitude. The effect of the temperature and density of lighter ions gives insight into the switching of compressive and rarefractive nature of the solutions. The compressive and rarefractive regimes of these solitary waves are analyzed and reported for the first time.

We study the stability of the ion-acoustic (IA) wave in a collisional plasma composed of hydrogen, positively and negatively charged oxygen ions, electrons and neutral atoms. This composition approximates very well the plasma environment around a comet. A solution of the dispersion relation yields a frequency for the IA wave at around the hydrogen plasma frequency. The growth/ damping rate is sensitively dependent on the ring parameters s u ⊥ (the ring speed) and ts v (the thermal spread). The growth rate of the wave, which decreases with increasing collisional frequencies, is larger when s ts u v ⊥ <. In the presence of negatively charged oxygen ions, the phase and group velocities of the IA wave behave in a contrasting manner when s ts u v ⊥ < (and viceversa). We propose that this behaviour be exploited as a diagnostic tool for the detection of these ions and also their thermalization.