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Research Paper | Physics Science | India | Volume 3 Issue 8, August 2014

Stability of the Ion-Acoustic Wave in Permeating Plasmas: Application to Comets

Sreekala G. ^[2] | Sijo Sebastian ^[3] | Noble P. Abraham ^[3] | Manesh Michael ^[3] | Neethu Theresa Willington | G. Renuka ^[4] | Chandu Venugopal ^[3]

Abstract: The ion-acoustic (IA) wave is a mode that is easily excited when the electron streaming velocity exceeds the ion-acoustic phase speed. We study the stability of this wave when a streaming quasi-neutral electron-ion plasma passes through another quasi-neutral pair-ion electron target plasma. Such a situation occurs when the solar wind (the streaming component consisting of hydrogen (H+) and solar wind electrons (`se')) flows past a comet. The cometary pair-ion electron plasma is composed of positively charged oxygen ions (O+), negatively charged oxygen ions (O-) and cometary electrons (`ce'). All five constituents have been modeled by kappa distribution functions. We find that the growth rate of the IA wave, which occurs under zero-current conditions, decreases with increasing spectral indices of the kappa distributions. The growth rate which increases with increasing O+ and O- densities and electron flow speeds, decreases with increasing hydrogen densities.

Keywords: ion-acoustic wave, permeating, kappa distribution, growth rate

Edition: Volume 3 Issue 8, August 2014,

Pages: 1297 - 1300

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