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has been cited by the following article:

• TITLE: Negatively Charged Oxygen Ions as a Plasma Diagnostic Tool: Application to Comets

  AUTHORS: Sreekala Gopinathan, Sijo Sebastian, Noble Abraham, Savithri Devi, Venugopal Chandu, Renuka Gangadharan

  KEYWORDS: Ion-Acoustic Wave, Negative Ions, Diagnostic Tool, Cometary Plasma

  JOURNAL NAME: Open Access Library Journal, Vol.1 No.4, July 30, 2014

  ABSTRACT: 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 μ ⊥s (the ring speed) and ν ts (the thermal spread). The growth rate of the wave, which decreases with increasing collisional frequencies, is larger when μ ⊥s ν ts. In the presence of negatively charged oxygen ions, the phase and group velocities of the IA wave behave in a contrasting manner when μ ⊥s ν ts (and viceversa). We propose that this behaviour be exploited as a diagnostic tool for the detection of these ions and also their thermalization.