8-12 July 2013
Africa/Johannesburg timezone
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Electrostatic wave Instabilities driven by counter-streaming electron beams in space plasmas

Presented by Mr. Lifa MBULI on 10 Jul 2013 from 15:40 to 16:00
Type: Oral Presentation
Session: Space Science
Track: Track D2 - Space Science

Abstract

Broadband electrostatic noise(BEN) observed in satellite data is found to be associated with field-aligned electron or ion beams in different regions of the magnetosphere such as the plasma sheet boundary layer(PSBL), bow shock and auroral kilometric radiation(AKR) regions. We consider a four-component plasma composed of drifting (parallel to ambient magnetic field) warm electrons and drifting (anti-parallel to ambient magnetic field) cool electrons and background hot electrons and ions in an attempt to further understand the excitation mechanisms for BEN. Using kinetic theory, electrostatic instabilities such as ion-acoustic, electron-acoustic and counter-streaming beam-resonant instabilities are found to be supported. The dependence of the instability growth rates and real frequencies on various plasma parameters such as cool electron beam speed, number density, temperature and temperature anisotropy, as well as the magnetic field strength are examined. It is found that cool electron beam number density and speed determines which instability can be excited. Using plasma parameters which are closely aligned with the measurements made by the Cluster satellites in the PSBL regions we find that the electron-acoustic and ion-acoustic instabilities could account for the generation of BEN in this region.

Award

Yes

Level

MSc

Supervisor

Ramesh Bharuthram, rbharuthram@uwc.ac.za, University of the Western Cape

Paper

Yes

Place

Location: A1-17


Primary authors

  • Mr. Lifa MBULI South African National Space Agency (SANSA) Space Science, P.O Box 32, Hermanus 7200, South Africa / Department of Physics, University of the Western Cape, Robert Sobukwe Road, Bellville 7535, South Africa
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Co-authors

  • Dr. Shimul MAHARAJ South African National Space Agency (SANSA) Space Science, P.O Box 32, Hermanus 7200, South Africa
  • Prof. Ramesh BHARUTHRAM University of the Western Cape, Office of the Deputy Vice-Chancellor (Academic), Robert Sobukwe Road, Bellville 7535, South Africa
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