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Title: Electron-acoustic solitary waves in the presence of a suprathermal electron component

Journal Article · · Physics of Plasmas
DOI:https://doi.org/10.1063/1.3606365· OSTI ID:22046892
; ;  [1];  [2]
  1. Centre for Plasma Physics, Department of Physics and Astronomy, Queen's University Belfast, Belfast BT7 1NN, Northern Ireland (United Kingdom)
  2. School of Physics, University of KwaZulu-Natal, Private Bag X54001, Durban 4000 (South Africa)

The nonlinear dynamics of electron-acoustic localized structures in a collisionless and unmagnetized plasma consisting of ''cool'' inertial electrons, ''hot'' electrons having a kappa distribution, and stationary ions is studied. The inertialess hot electron distribution thus has a long-tailed suprathermal (non-Maxwellian) form. A dispersion relation is derived for linear electron-acoustic waves. They show a strong dependence of the charge screening mechanism on excess suprathermality (through {kappa}). A nonlinear pseudopotential technique is employed to investigate the occurrence of stationary-profile solitary waves, focusing on how their characteristics depend on the spectral index {kappa}, and the hot-to-cool electron temperature and density ratios. Only negative polarity solitary waves are found to exist, in a parameter region which becomes narrower as deviation from the Maxwellian (suprathermality) increases, while the soliton amplitude at fixed soliton speed increases. However, for a constant value of the true Mach number, the amplitude decreases for decreasing {kappa}.

OSTI ID:
22046892
Journal Information:
Physics of Plasmas, Vol. 18, Issue 7; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
Country of Publication:
United States
Language:
English