skip to main content

Title: A Schamel equation for ion acoustic waves in superthermal plasmas

An investigation of the propagation of ion acoustic waves in nonthermal plasmas in the presence of trapped electrons has been undertaken. This has been motivated by space and laboratory plasma observations of plasmas containing energetic particles, resulting in long-tailed distributions, in combination with trapped particles, whereby some of the plasma particles are confined to a finite region of phase space. An unmagnetized collisionless electron-ion plasma is considered, featuring a non-Maxwellian-trapped electron distribution, which is modelled by a kappa distribution function combined with a Schamel distribution. The effect of particle trapping has been considered, resulting in an expression for the electron density. Reductive perturbation theory has been used to construct a KdV-like Schamel equation, and examine its behaviour. The relevant configurational parameters in our study include the superthermality index κ and the characteristic trapping parameter β. A pulse-shaped family of solutions is proposed, also depending on the weak soliton speed increment u{sub 0}. The main modification due to an increase in particle trapping is an increase in the amplitude of solitary waves, yet leaving their spatial width practically unaffected. With enhanced superthermality, there is a decrease in both amplitude and width of solitary waves, for any given values of the trappingmore » parameter and of the incremental soliton speed. Only positive polarity excitations were observed in our parametric investigation.« less
Authors:
;  [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. Centre for Plasma Physics, Department of Physics and Astronomy, Queen's University Belfast, BT7 1NN, Northern Ireland (United Kingdom)
  2. Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281, B-9000 Gent (Belgium)
  3. (South Africa)
  4. School of Chemistry and Physics, University of KwaZulu-Natal, Durban 4000 (South Africa)
  5. Department of Physics, Begum Rokeya University, Rangpur, Rangpur-5400 (Bangladesh)
Publication Date:
OSTI Identifier:
22303613
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 9; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ADMINISTRATIVE PROCEDURES; DISTRIBUTION FUNCTIONS; EQUATIONS; ION ACOUSTIC WAVES; IONS; PHASE SPACE; SOLITONS; TRAPPED ELECTRONS