Features of ion acoustic waves in collisional plasmas
- Centre for Plasma Astrophysics and Leuven Mathematical Modeling and Computational Science Centre (LMCC), K.U. Leuven, Celestijnenlaan 200B, 3001 Leuven (Belgium)
The effects of friction on the ion acoustic (IA) wave in fully and partially ionized plasmas are studied. In a quasineutral electron-ion plasma the friction between the two species cancels out exactly and the wave propagates without any damping. If the Poisson equation is used instead of the quasineutrality, however, the IA wave is damped and the damping is dispersive. In a partially ionized plasma, the collisions with the neutrals modify the IA wave beyond recognition. For a low density of neutrals the mode is damped. Upon increasing the neutral density, the mode becomes first evanescent and then reappears for a still larger number of neutrals. A similar behavior is obtained by varying the mode wavelength. The explanation for this behavior is given. In an inhomogeneous plasma placed in an external magnetic field, and for magnetized electrons and unmagnetized ions, the IA mode propagates in any direction and in this case the collisions make it growing on the account of the energy stored in the density gradient. The growth rate is angle dependent. A comparison with the collisionless kinetic density gradient driven IA instability is also given.
- OSTI ID:
- 21347109
- Journal Information:
- Physics of Plasmas, Vol. 17, Issue 2; Other Information: DOI: 10.1063/1.3309490; (c) 2010 American Institute of Physics; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COLLISIONAL PLASMA
COLLISIONS
ELECTRONS
INHOMOGENEOUS PLASMA
ION ACOUSTIC WAVES
IONS
POISSON EQUATION
CHARGED PARTICLES
DIFFERENTIAL EQUATIONS
ELEMENTARY PARTICLES
EQUATIONS
FERMIONS
ION WAVES
LEPTONS
PARTIAL DIFFERENTIAL EQUATIONS
PLASMA
PLASMA WAVES