KINETIC APPROACH TO THE INTERACTION OF A STREAM OF CHARGED PARTICLES WITH A STATIONARY PLASMA IN THE MAGNETIC FIELD. PART I
Discussion is given (based on the kinetic-equation method) of the instability of a stream of charged particles passing through a stationary magneto- active plasma and conditions are determined for wave amplification. It is assumed that the plasma and the stream are not bounded and that the ordered stream velocity v/sub o/ is in the direction of the external magnetic field H/sub o/. The direction of propagation of the waves is taken to be arbitrary and is determined by a wave vector k which makes an angle alpha with the direc tion of the external field H/sub o/. In the absence of this stream three types of waves can be propagated, namely, extraordinary, ordinary, and plasma. In the presence of a stream having a sufficiently low intensity, the refractive index for the above waves is changed only very slightly. However, in distinction to the case v/ sub o/ = O, it is possible for the waves to be amplified. Moreover, the order of the dispersion equation for the interaction of a stream with the plasma is increased and hence new types of waves can be propagated. In some cases, the instability may be associated with the amplification of this type of wave. A general dispersion equation is derived which determines the propagation of high- frequency waves in a magneto-active plasma. This equation is used in a discussion of the stability of plasma waves, and the stability and amplification (damping) coefficients for the extraordinary and ordinary waves are determined. The discussion takes into account thermal motion of particles in the stream. The results obtained by the kinetic-equation method for the instability of a stream of charged particles in a plasma and the amplification of electro-magnetic waves is interpreted in terms of the radiation emitted by electrons in a plasma. When charged particles move through a magneto-active plasma having a refractive index greater than unity, coherent bremsstrahlung and Cherenkov radiations are produced. The kinetic energy associated with the translational motion of the particles is thus partly converted into radiational energy and the density of this energy may increase. The part played by the plasma in this process is as follows. On the one hand, it ensures that the refractive index is in fact greater than unity, it retards the waves, and on the other hand, even in the absence of collisions, the amplification is prevented by the Landau effect. If the concentration of the particles in the stream is sufficiently high, the Landau damping cannot prevent the amplification of the field and the system becomes unstable (on the linear approximation). (OTS)
- Research Organization:
- Gorkii State Univ., U.S.S.R.
- NSA Number:
- NSA-15-028656
- OSTI ID:
- 4843197
- Journal Information:
- Izvest. Vysshykh Ucheb. Zavedenii, Radiofiz., Vol. Vol: 3; Other Information: Orig. Receipt Date: 31-DEC-61
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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