Parametric Coupling of Two Langmuir Waves in an Inhomogeneous Plasma, II. Stabilizing Effects Due to the Pondermotive Force Created by an Intense Pump Field

1976 ◽  
Vol 41 (1) ◽  
pp. 281-291 ◽  
Author(s):  
Tsutomu Ikemura
Keyword(s):  
Inhomogeneous Plasma ◽  
Pump Field ◽  
Langmuir Waves ◽  
Parametric Coupling ◽  
Pondermotive Force

scholarly journals Electron beam relaxation in inhomogeneous plasmas

2013 ◽  
Vol 31 (8) ◽  
pp. 1379-1385 ◽  
Author(s):  
A. Voshchepynets ◽  
V. Krasnoselskikh
Keyword(s):  
Electron Beam ◽  
Beam Energy ◽  
Electron Beams ◽  
Inhomogeneous Plasma ◽  
Density Fluctuations ◽  
Langmuir Waves ◽  
Wave Trapping ◽  
Beam Plasma ◽  
Beam Plasma Instability ◽  
Accelerated Particles

Abstract. In this work, we studied the effects of background plasma density fluctuations on the relaxation of electron beams. For the study, we assumed that the level of fluctuations was so high that the majority of Langmuir waves generated as a result of beam-plasma instability were trapped inside density depletions. The system can be considered as a good model for describing beam-plasma interactions in the solar wind. Here we show that due to the effect of wave trapping, beam relaxation slows significantly. As a result, the length of relaxation for the electron beam in such an inhomogeneous plasma is much longer than in a homogeneous plasma. Additionally, for sufficiently narrow beams, the process of relaxation is accompanied by transformation of significant part of the beam kinetic energy to energy of accelerated particles. They form the tail of the distribution and can carry up to 50% of the initial beam energy flux.

A drift of Langmuir waves in a magnetized inhomogeneous plasma

2019 ◽  
Vol 85 (1) ◽  
Author(s):  
Vasily I. Erofeev
Keyword(s):  
Energy Density ◽  
Plasma Physics ◽  
Wave Energy ◽  
Inhomogeneous Plasma ◽  
Magnetized Plasma ◽  
Plasma Inhomogeneity ◽  
Langmuir Waves ◽  
Plasma Kinetics ◽  
Nonlinear Plasma ◽  
Wave Energy Density

The concept of informativeness of nonlinear plasma physics scenarios is explained. Natural ideas of developing highly informative models of plasma kinetics are spelled out. They are applied to develop a formula that governs the drift of long Langmuir waves in spatial positions and wave vectors in a magnetized plasma due to the plasma inhomogeneity. Together with previous findings (Erofeev, Phys. Plasmas, vol. 22, 2015, 092302), the formula evidences the need for an intelligent generalization of the notion of wave energy density from usual homogeneous plasmas to inhomogeneous ones.

The Conversion of Langmuir Waves in the Inhomogeneous Plasma

1981 ◽  
Vol 24 (3) ◽  
pp. 566-574 ◽  
Author(s):  
N S Buchelnikova ◽  
E P Matochkin
Keyword(s):  
Inhomogeneous Plasma ◽  
Langmuir Waves

scholarly journals A new hydrodynamic analysis of double layers

1987 ◽  
Vol 5 (2) ◽  
pp. 269-286 ◽  
Author(s):  
M. P. Goldsworthy ◽  
F. Green ◽  
H. Hora
Keyword(s):  
Electric Fields ◽  
Second Harmonic ◽  
Fluid Model ◽  
Inhomogeneous Plasma ◽  
Macroscopic Model ◽  
Double Layers ◽  
Astrophysical Plasmas ◽  
Langmuir Waves ◽  
Hydrodynamic Description ◽  
Very High

A Genuine two-fluid model of plasmas with collisions permits the calculation of dynamic electric fields and double layers inside plasmas including oscillations and damping. For the first time a macroscopic model for coupling of electromagnetic and Langmuir waves was achieved with realistic damping. Starting points were laser produced plasmas showing very high dynamic electric fields in nonlinear force produced cavitons and inverted layers, in agreement with experiments. Applications for any inhomogeneous plasma as in laboratory or in astrophysical plasmas can then be followed up by a transparent hydrodynamic description. We find the rotation of plasmas in magnetic fields and a new second harmonic resonance. Explanation of inverted double layers, second harmonic emission from laser produced plasmas, and laser acceleration of charged particles by the very high fields of the double layers is given.

scholarly journals Fundamental Electromagnetic Emissions by a Weak Electron Beam in Solar Wind Plasmas with Density Fluctuations

2022 ◽  
Vol 924 (2) ◽  
pp. L24
Author(s):  
C. Krafft ◽  
P. Savoini
Keyword(s):  
Electron Beam ◽  
Electromagnetic Radiation ◽  
Inhomogeneous Plasma ◽  
Langmuir Wave ◽  
Density Fluctuations ◽  
Electromagnetic Energy ◽  
Langmuir Waves ◽  
Harmonic Emission ◽  
Electromagnetic Emissions ◽  
Weak Electron

Abstract The generation of Langmuir wave turbulence by a weak electron beam in a randomly inhomogeneous plasma and its subsequent electromagnetic radiation are studied owing to two-dimensional particle-in-cell simulations in conditions relevant to type III solar radio bursts. The essential impact of random density fluctuations of average levels of a few percents of the background plasma on the characteristics of the electromagnetic radiation at the fundamental plasma frequency ω p is shown. Not only wave nonlinear interactions but also processes of Langmuir waves’ transformations on the density fluctuations contribute to the generation of such emissions. During the beam relaxation, the amount of electromagnetic energy radiated at ω p in a plasma with density fluctuations strongly exceeds that observed when the plasma is homogeneous. The fraction of Langmuir wave energy involved in the generation of electromagnetic emissions at ω p saturates around 10−4, i.e., one order of magnitude above that reached when the plasma is uniform. Moreover, whereas harmonic emission at 2ω p dominates over fundamental emission during the time evolution in a homogeneous plasma, fundamental emission is strongly dominant when the plasma contains density fluctuations, at least during several thousands of plasma periods before being overcome by harmonic emission when the total electromagnetic energy begins to saturate.

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