Nonlinear behaviour of a finite amplitude electron plasma wave, III. The sideband instability

1978 ◽  
Vol 360 (1701) ◽  
pp. 229-242 ◽  
Keyword(s):  
Distribution Function ◽  
Plasma Wave ◽  
Electron Distribution ◽  
Wave Amplitude ◽  
Electron Distribution Function ◽  
Electron Plasma ◽  
Finite Amplitude ◽  
Nonlinear Behaviour ◽  
Experimental Conditions ◽  
Electron Plasma Wave

Computations of the evolution of the electron distribution function in a plasma subsequent to the excitation of a constant finite amplitude electron plasma wave show that the system is stable for plasma parameters for which under experimental conditions the sideband instability is found to be excited. When the time (or space) variation of wave amplitude is included a group of particles initially trapped is detrapped and then behaves like an electron beam passing through the plasma. The experimental dispersion of test waves in a low density plasma is compared with theoretical predictions for parameters given by the detrapping model. Further, measurements of the electron distribution function in the presence of a finite amplitude wave as a function of position, wave amplitude, and wave frequency, show features which are consistent only with a detrapped beam.

Steady nonlinear electrostatic plasma wave in a weak transverse magnetic field

2007 ◽  
Vol 73 (2) ◽  
pp. 179-188 ◽  
Author(s):  
V.L. KRASOVSKY
Keyword(s):  
Magnetic Field ◽  
Distribution Function ◽  
Plasma Wave ◽  
Electron Distribution Function ◽  
Density Perturbation ◽  
Transverse Magnetic ◽  
Physical Structure ◽  
Finite Amplitude ◽  
Resonant Region ◽  
Electrostatic Plasma Wave

Abstract.The structure of a stationary electrostatic plasma wave propagating at a right angle to a weak magnetic field is studied. It is shown that the periodic finite amplitude wave is close in its physical structure to Bernstein–Greene–Kruskal wave of a perfectly definite type. The distinguishing feature of such a nonlinear wave is the absence of the resonant particles trapped by the wave. The electron distribution function, density perturbation and the shape of the wave electrostatic potential are found. The nonlinear dispersion relation is derived to determine the frequency shift due to the perturbation of the distribution function in the resonant region.

Nonlinear behaviour of a finite amplitude electron plasma wave - IV. Decay to ion cyclotron waves

1978 ◽  
Vol 363 (1715) ◽  
pp. 547-557
Keyword(s):  
Magnetic Field ◽  
Low Frequency ◽  
Electron Plasma ◽  
Finite Amplitude ◽  
Nonlinear Behaviour ◽  
Electron Plasma Wave ◽  
Ion Cyclotron Waves ◽  
Ion Cyclotron ◽  
Low Frequency Mode ◽  
The Magnetic Field

Plasma in a magnetic field displays low frequency modes near the ion cyclotron frequency for waves propagating at an angle to the magnetic field. These modes are only slightly modified in a bounded plasma, and therefore can be excited by nonlinear decay of electron plasma waves which also propagate at an angle to the magnetic field. The nonlinearly generated low frequency mode has been identified experimentally as an ion cyclotron wave by stimulating the decay. The resonant matching conditions have also been demonstrated.

scholarly journals Quasi-linear dynamics of Weibel instability

2011 ◽  
Vol 29 (11) ◽  
pp. 1997-2001 ◽  
Author(s):  
O. A. Pokhotelov ◽  
O. A. Amariutei
Keyword(s):  
Distribution Function ◽  
Electron Distribution ◽  
Wave Amplitude ◽  
Electron Distribution Function ◽  
Resonant Interaction ◽  
Nonlinear Saturation ◽  
Linear Dynamics ◽  
Electrostatic Waves ◽  
Substantial Modification ◽  
Resonant Region

Abstract. The quasi-linear dynamics of resonant Weibel mode is discussed. It is found that nonlinear saturation of Weibel mode is accompanied by substantial modification of the distribution function in resonant region. With the growth of the wave amplitude the parabolic bell-like form of the electron distribution function in this region converts into flatter shape, such as parabola of the fourth order. This results in significant weakening of the resonant interaction of the wave with particles. The latter becomes weaker and then becomes adiabatic interaction with the bulk of the plasma. This is similar to the case of Bernstein-Greene-Kruskal (Bernstein et al., 1957) electrostatic waves. The mathematical similarity of the Weibel and magnetic mirror instabilities is discussed.

Photoionisation en milieu rigide. Evolution de la fonction de distribution des électrons piégés autour des cations

1973 ◽  
Vol 51 (20) ◽  
pp. 3428-3434 ◽  
Author(s):  
Jacques Bullot ◽  
Dominique Ceccaldi ◽  
Odile Gallais
Keyword(s):  
Distribution Function ◽  
Light Intensity ◽  
Electron Distribution ◽  
Numerical Solutions ◽  
Electron Distribution Function ◽  
Coulomb Field ◽  
Experimental Conditions ◽  
Recombination Luminescence ◽  
Trapped Electrons ◽  
Trapped Electron

A kinetic model for describing isothermal recombination luminescence (ITL) of trapped electrons in a rigid medium is proposed. Assuming that cavities in the glass are pre-existing, a continuous trap-depth distribution is generated from the long-range Coulomb field of the cation. ITL decay kinetics simply is the superposition of an infinite sum of first order decays of correlated electrons. This model is able to fit experimental decays within ± 3%. Numerical solutions are tested by introducing a Gaussian trapped electron distribution function (parameters: rmax Å and width b Å) and keeping the formerly found trap parameters: half-width L = 1.70 Å and lifetime at infinity [Formula: see text]. This model is used for studying how the trapped electron distribution function is shifted when experimental conditions are altered. (1) During the glass isothermal relaxation. The initial values rmax = 32.0 Å, b = 6.2 Å found just after cooling are shifted to rmax = 40.0 Å and b = 9.0 Å, 24 h after cooling. The model indicates that the total number of trapped electrons is steadily decreasing as long as the relaxation is proceeding. (2) As a function of the u.v. irradiation period. The trapped electron distribution function is pushed away from the cationic center when tirrad is increasing. Near the saturation plateau the distribution function is no longer shifted; only the total number of trapped electrons is increased. (3) As a function of u.v. light intensity. By integrating as a function of r the trapped electron distribution function at time t = 0 when u.v. light is turned off, the resulting area, which is proportional to the total number of trapped electrons, is shown to be proportional to the square of the light intensity. In others words with this model the well-known one-electron two-photon ionization law is recovered. This is to be considered as a test of the model self-consistency.

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