Electron-acoustic solitary waves in the presence of a suprathermal electron component
Abstract
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 κ). 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 κ, 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 κ.
- Publication:
-
Physics of Plasmas
- Pub Date:
- July 2011
- DOI:
- 10.1063/1.3606365
- arXiv:
- arXiv:1107.5226
- Bibcode:
- 2011PhPl...18g2902D
- Keywords:
-
- hot carriers;
- plasma electrostatic waves;
- plasma nonlinear processes;
- plasma solitons;
- 52.35.Sb;
- 52.35.Mw;
- 52.35.Fp;
- 72.30.+q;
- Solitons;
- BGK modes;
- Nonlinear phenomena: waves wave propagation and other interactions;
- Electrostatic waves and oscillations;
- High-frequency effects;
- plasma effects;
- Astrophysics - Solar and Stellar Astrophysics;
- Nonlinear Sciences - Pattern Formation and Solitons;
- Physics - Plasma Physics
- E-Print:
- 11 pages, 7 figures