Nonlinear excitations in electron-positron-ion plasmas in accretion disks of active galactic nuclei
- Institut fuer Theoretische Physik IV, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum, Germany and Department of Physics, Faculty of Education-Port Said, Suez Canal University (Egypt)
The propagation of acoustic nonlinear excitations in an electron-positron-ion (e-p-i) plasma composed of warm electrons and positrons, as well as hot ions, has been investigated by adopting a two-dimensional cylindrical geometry. The electrons and positrons are modeled by hydrodynamic fluid equations, while the ions are assumed to follow a temperature-parametrized Boltzmann distribution (the fixed ion model is recovered in the appropriate limit). This situation applies in the accretion disk near a black hole in active galactic nuclei, where the ion temperature may be as high as 3 to 300 times that of the electrons. Using a reductive perturbation technique, a cylindrical Kadomtsev-Petviashvili equation is derived and its exact soliton solutions are presented. Furthermore, real situations in which the strength of the nonlinearity may be weak are considered, so that higher-order nonlinearity plays an important role. Accordingly, an extended cylindrical Kadomtsev-Petviashvili equation is derived, which admits both soliton and double-layer solutions. The characteristics of the nonlinear excitations obtained are investigated in detail.
- OSTI ID:
- 21062025
- Journal Information:
- Physics of Plasmas, Vol. 14, Issue 10; Other Information: DOI: 10.1063/1.2795127; (c) 2007 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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Related Subjects
GENERAL PHYSICS
ACCRETION DISKS
ASTROPHYSICS
BLACK HOLES
CYLINDRICAL CONFIGURATION
DISTRIBUTION
ELECTRONS
EQUATIONS
EXCITATION
GALAXIES
GEOMETRY
ION TEMPERATURE
IONS
MATHEMATICAL SOLUTIONS
NONLINEAR PROBLEMS
PERTURBATION THEORY
PLASMA
POSITRONS
SOLITONS
TWO-DIMENSIONAL CALCULATIONS