Langmuir wave-packet generation from an electron beam propagating in the inhomogeneous solar wind

2010 ◽  
Author(s):  
A. Zaslavsky ◽  
A. S. Volokitin ◽  
V. V. Krasnoselskikh ◽  
M. Maksimovic ◽  
S. D. Bale ◽  
...  
Keyword(s):  
Solar Wind ◽  
Electron Beam ◽  
Wave Packet ◽  
Langmuir Wave

scholarly journals Particle-in-cell simulations of the relaxation of electron beams in inhomogeneous solar wind plasmas

2016 ◽  
Vol 82 (6) ◽  
Author(s):  
Jonathan O. Thurgood ◽  
David Tsiklauri
Keyword(s):  
Solar Wind ◽  
Electron Beam ◽  
Linear Theory ◽  
Langmuir Wave ◽  
High Energy ◽  
Density Fluctuations ◽  
Langmuir Waves ◽  
Particle In Cell ◽  
Hamiltonian Models ◽  
Beam Plasma

Previous theoretical considerations of electron beam relaxation in inhomogeneous plasmas have indicated that the effects of the irregular solar wind may account for the poor agreement of homogeneous modelling with the observations. Quasi-linear theory and Hamiltonian models based on Zakharov’s equations have indicated that when the level of density fluctuations is above a given threshold, density irregularities act to de-resonate the beam–plasma interaction, restricting Langmuir wave growth on the expense of beam energy. This work presents the first fully kinetic particle-in-cell (PIC) simulations of beam relaxation under the influence of density irregularities. We aim to independently determine the influence of background inhomogeneity on the beam–plasma system, and to test theoretical predictions and alternative models using a fully kinetic treatment. We carry out one-dimensional (1-D) PIC simulations of a bump-on-tail unstable electron beam in the presence of increasing levels of background inhomogeneity using the fully electromagnetic, relativistic EPOCH PIC code. We find that in the case of homogeneous background plasma density, Langmuir wave packets are generated at the resonant condition and then quasi-linear relaxation leads to a dynamic increase of wavenumbers generated. No electron acceleration is seen – unlike in the inhomogeneous experiments, all of which produce high-energy electrons. For the inhomogeneous experiments we also observe the generation of backwards-propagating Langmuir waves, which is shown directly to be due to the refraction of the packets off the density gradients. In the case of higher-amplitude density fluctuations, similar features to the weaker cases are found, but also packets can also deviate from the expected dispersion curve in $(k,\unicode[STIX]{x1D714})$-space due to nonlinearity. Our fully kinetic PIC simulations broadly confirm the findings of quasi-linear theory and the Hamiltonian model based on Zakharov’s equations. Strong density fluctuations modify properties of excited Langmuir waves altering their dispersion properties.

scholarly journals Dependence of Langmuir wave polarization on electron beam speed in type III solar radio bursts

2011 ◽  
Vol 38 (13) ◽  
pp. n/a-n/a ◽  
Author(s):  
David M. Malaspina ◽  
Iver H. Cairns ◽  
Robert E. Ergun
Keyword(s):  
Electron Beam ◽  
Solar Radio ◽  
Langmuir Wave ◽  
Radio Bursts ◽  
Wave Polarization ◽  
Solar Radio Bursts ◽  
Type Iii

Effects of a cold electron beam on the parametric decay of a Langmuir wave

1984 ◽  
Vol 56 (11) ◽  
pp. 3132-3136 ◽  
Author(s):  
Joseph E. Willett ◽  
Yildirim Aktas
Keyword(s):  
Electron Beam ◽  
Langmuir Wave ◽  
Cold Electron ◽  
Parametric Decay

scholarly journals An electron wave packet in the relativistic strophotron FEL

2021 ◽  
Vol 19 (1) ◽  
pp. 016001
Author(s):  
K B Oganesyan ◽  
M Hnatic ◽  
P Kopchancky
Keyword(s):  
Electron Beam ◽  
Wave Packet ◽  
Initial Distribution ◽  
Quantum Mechanical ◽  
Initial Moment ◽  
Electron Wave ◽  
Electron Wave Packet ◽  
Vibrational Levels ◽  
Mechanical Approach ◽  
Quantum Mechanical Approach

Abstract The theory of free electron lasers (FELs) is well developed both in quantum mechanical and classical approaches. In strophotron FEL, in classical approach, resonance frequency and the gain are strongly dependent on initial parameters of electron beam. In the quantum mechanical approach considered by Zaretsky and Nersesov (1983 JETP 57 518), there is no such dependence. The correspondence between the quantum mechanical and classical approaches in a relativistic strophotron FEL is discussed. We study the initial distribution of electrons over vibrational levels determined by the expansion coefficients in relativistic strophotron FEL. It is shown, (presenting electron wave function in the form of Gaussian wave packet), that the number of the vibrational level most efficiently populated at the initial moment of time can be expressed in terms of the initial parameters of the electron beam.

Sign in / Sign up

Export Citation Format

Share Document