Nonlinear Plasma Theory

Electron diffusion in the fast-axial-flow CO2 laser

In a number of experiments on ozone layer investigations the short-term ozone variations with hour or several hours periods at heights 20 - 50 km were observed. We suppose that this phenomenon may originate due to interaction of internal gravity waves with stratified shear flow in the vicinity of critical layer, where the phase velocity of the wave is equal to flow velocity. The amplitude and period of ozone density oscillations are found in the gravity wave of constant amplitude, when the flow pattern near the critical layer is determined by nonlinearity, and viscosity effects are small. We have found that the density variation of passive admixture can be comparable with unperturbed value.

Ozone variations in the stratosphere due to gravity waves in stratified shear flows

The nonlinear evolution of initially monoenergetic (v(t=0)=(0,0,u)) electron beam propagating in a nonmagnetized dielectric medium of permittivity in >1, with initial velocity u>or=c/ square root in (where c is the vacuum speed of light) is investigated. The specific instability of the beam under such conditions is the cause of the generation of a broad spectrum of transverse electromagnetic waves coupled to the simultaneous excitation of the second harmonic of the beam's oscillations, both at the expense of the beam's initial kinetic energy. The system of self-consistent nonlinear equations, describing the particle-field dynamics, is treated in the spirit of the weak-turbulence approach. The integrals of the resulting nonlinear system of equations for the amplitudes of the fields of the electron density are used to evaluate the spectral distribution of the amplitudes in the saturation phase, and hence the efficiency of the transformation of the beam's energy into electromagnetic radiation as a function of the width of the spectrum of the initially present electromagnetic fluctuations. A substantial increase in this efficiency is observed in comparison with the single-mode case.

http://iopscience.iop.org/article/10.1088/0741-3335/32/9/002/pdf

Weak turbulence and broad-spectrum excitation in a nonmagnetized electron beam via second-harmonic generation

Classification of instabilities is discussed, but the approach adopted is a systematic development from the Vlasov equation, generalising the concepts of Landau damping and using adiabatic approximations when these are valid The best understood classes of instability are dominated by resonance and for these the most important nonlinear effect is quasi-linear diffusion Wave-wave interactions and non-resonant diffusion are not discussed

Instabilities in the Magnetosphere (Theoretical Treatment)

Induced Compton scattering of photons — and nonlinear Landau damping of plasmons — by plasma particles are governed by the same type of nonlinear integrodifferential kinetic equation. Numerical time evolution of a large class of initial spectra leads to soliton like behaviour. Only a finite number of exact invariants of motion exist and collisions between solitons are performed in order to test their structural stability.

Nonlinear Plasma Theory

Citations

Electron diffusion in the fast-axial-flow CO2 laser

Ozone variations in the stratosphere due to gravity waves in stratified shear flows

Weak turbulence and broad-spectrum excitation in a nonmagnetized electron beam via second-harmonic generation

Instabilities in the Magnetosphere (Theoretical Treatment)

Nonlinear kinetic equation in plasma physics leading to soliton structures

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