scholarly journals Dromion solutions for nonlinear electron acoustic waves in space plasmas

2002 ◽  
Vol 9 (5/6) ◽  
pp. 463-475 ◽  
Author(s):  
S. S. Ghosh ◽  
A. Sen ◽  
G. S. Lakhina

Abstract. Recent high resolution measurements of POLAR and FAST satellites have revealed two-dimensional coherent structures in the polar cap boundary layer (PCBL) region. Since the ion temperature is often observed to be greater than the electron temperature in this region, electron acoustic waves can exist as a normal mode of the plasma system. It is shown that the nonlinear evolution of such waves can be modelled by the coupled Davey-Stewartson I equations. These equations, which are a generalization of the nonlinear Schrödinger equation to two dimensions, admit exponentially localized solutions called dromions. A detailed parametric characterization of the regions of existence of such solutions is presented in the context of the PCBL region.

1989 ◽  
Vol 41 (2) ◽  
pp. 281-287
Author(s):  
M. B. Chaudhry ◽  
M. D. Tahir

Ion-acoustic waves in sheet plasmas, which are of thickness of order of the ion Larmor radius ρi, have been investigated numerically. The frequency range considered is less than the ion cyclotron frequency ωci. An integral equation in wavenumber space is derived from the linearized Vlasov-Poisson equations and analysed numerically. Eigenfrequencies and eigenfunctions of the wave have been studied systematically by varying the plasma thickness, plasma density, electron-to-ion temperature ratio and parallel wavenumber. Electron-acoustic waves are found when the parallel wavenumber is very small (e.g. k∥ρi = 0·005) and the electron and ion temperatures are comparable.


1980 ◽  
Vol 24 (1) ◽  
pp. 169-180 ◽  
Author(s):  
B. Buti

Propagation of electron-acoustic waves in a strongly nonlinear magnetoplasma with two ion species is investigated. The presence of the second ion component affects the dynamics of these solitary waves in a variety of ways. Besides solitons, supersonic holes (density depressions) are produced by sufficiently large- amplitude perturbations. Heavier and hotter ions are more favourable to the holes. Applications of the present investigations to space plasmas are pointed out.


2000 ◽  
Vol 105 (A6) ◽  
pp. 12919-12927 ◽  
Author(s):  
D. Schriver ◽  
M. Ashour-Abdalla ◽  
V. Sotnikov ◽  
P. Hellinger ◽  
V. Fiala ◽  
...  

Pramana ◽  
2015 ◽  
Vol 86 (4) ◽  
pp. 873-883 ◽  
Author(s):  
KAUSHIK ROY ◽  
SWAPAN KUMAR GHOSH ◽  
PRASANTA CHATTERJEE

2018 ◽  
Vol 25 (10) ◽  
pp. 102115 ◽  
Author(s):  
Pavel A. Andreev ◽  
S. V. Kolesnikov

2014 ◽  
Vol 32 (8) ◽  
pp. 975-989 ◽  
Author(s):  
R. A. Treumann ◽  
W. Baumjohann

Abstract. Coagulation of electrons to form macro-electrons or compounds in high temperature plasma is not generally expected to occur. Here we investigate, based on earlier work, the possibility for such electron compound formation (non-quantum "pairing") mediated in the presence of various kinds of plasma waves via the generation of attractive electrostatic potentials, the necessary condition for coagulation. We confirm the possibility of production of attractive potential forces in ion- and electron-acoustic waves, pointing out the importance of the former and expected consequences. While electron-acoustic waves presumably do not play any role, ion-acoustic waves may potentially contribute to formation of heavy electron compounds. Lower-hybrid waves also mediate compound formation but under different conditions. Buneman modes which evolve from strong currents may also potentially cause non-quantum "pairing" among cavity-/hole-trapped electrons constituting a heavy electron component that populates electron holes. The number densities are, however, expected to be very small and thus not viable for justification of macro-particles. All these processes are found to potentially generate cold compound populations. If such electron compounds are produced by the attractive forces, the forces provide a mechanism of cooling a small group of resonant electrons, loosely spoken, corresponding to classical condensation.


2006 ◽  
Author(s):  
Francesco Valentini ◽  
Thomas M. O’Neil ◽  
Daniel H. E. Dubin

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