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

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DOI: 10.4236/oalib.1100570    1,294 Downloads   1,543 Views  


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.

Conflicts of Interest

The authors declare no conflicts of interest.

Cite this paper

Gopinathan, S. , Sebastian, S. , Abraham, N. , Devi, S. , Chandu, V. and Gangadharan, R. (2014) Negatively Charged Oxygen Ions as a Plasma Diagnostic Tool: Application to Comets. Open Access Library Journal, 1, 1-9. doi: 10.4236/oalib.1100570.


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