Nonlinear Interaction Of Plasma Waves Research Articles

A simulation study of electron-scale turbulence generation by nonlinear wave–wave interaction in laser-produced plasmas

A laboratory simulation of a model based on the nonlinear interaction of plasma waves is presented to study the electron-scale magnetic turbulence in the magnetized plasma. In this perspective, the model equations of the Trivelpiece–Gould (TG) mode and extraordinary mode (pump wave) are developed, taking the relativistic change in electron mass and the ponderomotive force into account. Laboratory simulations utilizing the pseudo-spectral method along with the predictor–corrector scheme and finite difference method are performed to solve the formulated coupled model equations. The propagation angle (θ) of the TG mode from the magnetic field affects the dispersive properties of the dynamics (TG mode), which, in turn, impact the density perturbation, scale size of the filamentary structures, density harmonics, magnetic field enhancement, and the spectral index of the turbulence generation. The simulation results reveal that the observed turbulent spectra resemble the magnetic turbulence reported in various studies of the interaction of the intense laser with plasma at the laboratory astrophysics scale relevant to astrophysical events. A simplified model in the paraxial limit is also given to understand the effect of the propagation direction (angle of propagation θ) of the TG mode on the localized structures of the pump laser beam in the magnetized plasma.

Phase speed of electrostatic waves: the critical parameter for efficient electron surfing acceleration

Particle acceleration by means of nonlinear plasma wave interactions is of great topical interest. Accordingly, in this paper we focus on the electron surfing process. Self-consistent kinetic simulations, using both relativistic Vlasov and particle-in-cell (PIC) approaches, show here that electrons can be accelerated to highly relativistic energies (up to 100mec2) if the phase speed of the electrostatic wave is mildly relativistic (0.6c to 0.9c for the magnetic field strengths considered). The acceleration is strong because of relativistic stabilization of the nonlinearly saturated electrostatic wave, seen in both relativistic Vlasov and PIC simulations. An inverse power law momentum distribution can arise for the most strongly accelerated electrons. These results are of relevance to observed rapid changes in the radio synchrotron emission intensities from microquasars, gamma ray bursts and other astrophysical objects that require rapid acceleration mechanisms for electrons.

Order and chaos in nonlinear wave interactions in astrophysical and space plasmas

We discuss the observation and theory of nonlinear wave interactions in astrophysical and space plasmas. Observational evidence of nonlinear mode-mode coupling in solar type III radio bursts, auroral whistler-mode radiation and active experiments in space is reviewed. The transition from order to chaos in nonlinear plasma wave interactions is analysed. For Hamiltonian four-wave interactions, the nonlinear dynamical process may undergo a chaotic transition via the quasi-periodicity route. For dissipative three-wave interactions, the nonlinear system may evolve from order to chaos via two different routes: period doubling and intermittency. It is shown that chaos in dissipative nonlinear three-wave coupling can be controlled by applying a small sinusoidal wave to the system.

Characteristics of an ECR ion beam source for low-pressure etching

We have investigated an ECR ion beam source operated with a pair of coils and a two-grid extraction optics. The most important parameter for the source operation at low pressure (p<10−3 mbar) is the magnetic field in the source. A basic understanding of the physics occurring in this source can be obtained by simply registrating the total ion beam current through the first grid as a function of the magnetic field from the coils. From these characteristics we find that for the wave-propagation through the plasma column the magnet next to the microwave feed (rear magnet) is the important one. The other one (front magnet) controls the electron losses if the plasma generation is mainly located in the rear magnet. For certain magnetic field distributions we find harmonics of the ECR resonance, indicating nonlinear plasma wave interactions occurring in the source.

Nonlinear Interaction of Plasma Waves in External Magnetic Field and the Possibility of Up‐Conversion

AbstractNonlinear interaction of low‐frequency resonant and high‐frequency nonresonant plasma oscillations in the presence of an external magnetic field is studied. In the case of Iongitudinal waves it is shown that the up‐conversion of plasma oscillations' energy is possible in such a system.

A third order scheme in the vlasov theory and some consequences in the evolution of few body systems

A set of implemented evolution equations, describing the coherent nonlinear interaction of plasma waves, based on the perturbation method, has been derived, taking into account initial value effects and third order nonlinearities in the modal amplitudes.

Nonlinear interaction of plasma waves in a cold magnetized plasma

The general coupling equation for the wave-wave scattering in a cold magnetized plasma is derived. Specifically, the transformation of electrostatic waves is studied in connection with solar type-III radiation. The relevant numerical analysis is also presented.

A weak turbulence analysis of the two-stream instability

In this investigation, we study the effects of non-linear interaction of plasma waves in the weak turbulence approximation on a stream-plasma system which is subject to the two-stream instability. The momentum distribution of the stream is assumed to be a Gaussian function and the background plasma is assumed to be a Maxwellian with a temperature T. The non-linear wave-particle interaction of induced scattering on the polarization clouds of ions may lead to stabilization of the stream—plasma waves in the resonant cone are scattered into the nonresonant region. The non-linear wave-particle interaction of induced scattering on the polarization clouds of ions may lead to stabilization of the stream; plasma waves in the resonant cone are scattered into the non-resonant region and vice versa, leading to a well-defined average energy density in plasma waves which is much less than the energy density of the stream. Non-linear scattering also causes transformation of plasma waves into electromagnetic radiation near the fundamental of the electron plasma frequency of the background plasma, and combination of two plasma waves leads to electromagnetic radiation near the second harmonic of this frequency. Expressions are given for the latter process for emission and absorption for arbitrary values of the ratio of the wave number of plasma waves to the wave number of the electromagnetic wave. The major features of the whole phenomenon are illustrated with the help of a numerical example, with conditions typical for the solar corona in which case an ion stream would be stabilized, but an electron or neutral stream (with the chosen density) would not.