Ion-acoustic waves in a plasma consisting of adiabatic warm ions, nonisothermal electrons, and a weakly relativistic electron beam: Linear and higher-order nonlinear effects
- Faculty of Science, Department of Physics, Azerbaijan University of Tarbiat Moallem, 51745-406 Tabriz (Iran, Islamic Republic of)
- Center for Plasma Physics (CPP), Department of Physics and Astronomy, Queen's University Belfast, BT7 1 NN Northern Ireland (United Kingdom)
- Institut fuer Theoretische Physik IV, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)
The nonlinear propagation of finite amplitude ion acoustic solitary waves in a plasma consisting of adiabatic warm ions, nonisothermal electrons, and a weakly relativistic electron beam is studied via a two-fluid model. A multiple scales technique is employed to investigate the nonlinear regime. The existence of the electron beam gives rise to four linear ion acoustic modes, which propagate at different phase speeds. The numerical analysis shows that the propagation speed of two of these modes may become complex-valued (i.e., waves cannot occur) under conditions which depend on values of the beam-to-background-electron density ratio {alpha}, the ion-to-free-electron temperature ratio {sigma}, and the electron beam velocity v{sub 0}; the remaining two modes remain real in all cases. The basic set of fluid equations are reduced to a Schamel-type equation and a linear inhomogeneous equation for the first and second-order potential perturbations, respectively. Stationary solutions of the coupled equations are derived using a renormalization method. Higher-order nonlinearity is thus shown to modify the solitary wave amplitude and may also deform its shape, even possibly transforming a simple pulse into a W-type curve for one of the modes. The dependence of the excitation amplitude and of the higher-order nonlinearity potential correction on the parameters {alpha}, {sigma}, and v{sub 0} is numerically investigated.
- OSTI ID:
- 21103809
- Journal Information:
- Physics of Plasmas, Vol. 15, Issue 2; Other Information: DOI: 10.1063/1.2836619; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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