Electron Wave Instabilities in a Magnetoplasma Caused by Electron-neutral Collisions PDF Download

Author: John Q. Howell
Publisher:
ISBN:
Category : Collision integrals
Languages : en
Pages : 122

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Book Description
A new class of collision-dependent electron waves is found in a non-Maxwellian Lorentz magnetoplasma, and it is shown that electron-neutral collisions may cause these waves to become unstable. The Boltzmann equation with collision integral is solved while assuming propagation to be either parallel or perpendicular to the magnetic field. Both conductivity tensors are derived and put in a form that is useful for numerical calculations. The full set of Maxwell's equations is then used to derive the dispersion relations for both directions of propagation. The dispersion relations are initially solved for a monoenergetic electron distribution function and then an isotropic distribution with a peak of nonzero half-width is treated. Some consideration is also given to an isotropic Maxwellian distribution both with and without a bump on the tail. As an example of propagation parallel to the magnetic field, transverse electromagnetic or "whistler" waves in a nitrogen plasma are considered. A new collisional mode is found with real frequency near the electron cyclotron frequency, and under appropriate conditions it may be either convectively or absolutely unstable. Longitudinal or electrostatic waves propagating perpendicular to the magnetic field in a nitrogen plasma are also considered. A series of new collisional modes with real frequency near the electron cyclotron frequency and its harmonics are shown to be unstable under some conditions. For both directions of propagation, the electron waves can be unstable if a large fraction of plasma electrons have their velocity in a region where the electron-neutral collision frequency increases (or decreases) rapidly enough. The requirement on the electron-neutral collision frequency is easily met by nitrogen, mercury, and the Ramsauer gases.