Nonlinear low-frequency structures in the auroral plasma in the presence of an oxygen beam including charge separation
- University of KwaZulu-Natal, Durban 4000 (South Africa)
- University of the Western Cape, Modderdam Road, Belville 7535 (South Africa)
- Indian Institute of Geomagnetism, New Panvel (W), Navi Mumbai 410218 (India)
Observations from the Fast Auroral SnapshoT (FAST) satellite indicate that the parallel and perpendicular (to the Earth's magnetic field) electric field structures exhibit a spiky appearance. In this study, a magnetized plasma system consisting of protons, electrons, and a cold oxygen ion beam is considered. Both background electrons and protons are treated as hot species with Boltzmann density distributions. The dynamics of the oxygen ion beam is governed by the fluid equations. Effect of charge separation is studied on nonlinear fluctuations arising from a coupling of ion cyclotron and ion-acoustic waves. A scan of parameter space reveals a range of solutions for the parallel electric field from sinusoidal to sawtooth to highly spiky waveforms. The inclusion of charge separation effects tends to in most cases increase the frequency of oscillation of the nonlinear structures. In the case of a weakly magnetized plasma, the amplitude of the oscillations are found to be constant while they are modulated for a strongly magnetized plasma. The findings are compared with satellite observations.
- OSTI ID:
- 21347128
- Journal Information:
- Physics of Plasmas, Vol. 17, Issue 2; Other Information: DOI: 10.1063/1.3299328; (c) 2010 American Institute of Physics; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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