Electrostatic waves in an electron-beam plasma system

Abstract

A one-dimensional ͑1D͒ electrostatic particle-in-cell simulation was performed to study wave excitation processes due to a tenuous electron beam in a plasma system, which is composed of hot and cold electron components. In this case, three types of electrostatic waves are excited, namely, Langmuir waves, electron-acoustic waves, and beam-driven waves. The beam-driven waves have a broad frequency spectrum, which extends from ͑0.1-0.2͒ pe ͑ pe is the electron plasma frequency͒ to ͑1.5-2.5͒ pe , with phase speeds close to the speed of the electron beam. The interactions among these waves are investigated for different values of density, temperature, and speed of the electron beam, etc. One special case is that when the density of the electron beam is sufficiently high, compressive solitary waves with bipolar structure of the electric field are generated. The generation mechanism of these solitons is mainly due to the trapping of a fraction of the beam electrons by the potential well of the enhanced beam-driven waves, as shown by the holes that are formed in phase-space plots. The relevance of these excited electrostatic waves to the intense broadband electrostatic noise observed in the Earth's auroral region is also discussed.

Study of nonlinear ion- and electron-acoustic waves in multi-component space plasmas

“…It cannot claim that the modes arise from the linear instability as happens in the simulations of Lu et al (2005) where an electron beam streaming at ∼10 cold electron thermal speeds or more drives the linear modes which saturates by trapping the electrons. In our case, the solitary structures are the nonlinear modes of the system, just as the BGK modes are the nonlinear modes of the VlasovPoisson system.…”

Ion-beam/plasma modes in ultradense relativistic quantum plasmas: Dispersion characteristics and beam-driven instability

“…ω 2 e = ω 2 pe H0 + ( cξo H0 ) 2 k 2 [30], should the other two species be neglected). Finally, the third term represents the beam, involving the beam plasma frequency ω pb and the beam velocity U b0 : neglecting the other two components, this term would lead to a beam-driven beam mode, ω b = kU b0 ± ω pb [21,22,32]. Qualitatively speaking, the above dispersion relation therefore represents a mixing between the three latter frequencies ω e,i,b , which are respectively modified due to interactions among them.…”

“…The excitation of electrostatic (ES) nonlinear localized waves [16,17] via ion beam injection into plasma has been studied theoretically, via small-amplitude [18,19] or largeamplitude nonlinear wave phenomenology [20] and also numerically, e.g. via particle-in-cell (PIC) simulations [21][22][23][24][25].…”

Electron-acoustic solitary structures in two-electron-temperature plasma with superthermal electrons

“…EA soliton has been considered as one of the possible candidates for some of the observed solitary structures. Recently, the propagation of the linear as well as nonlinear EAWs has received a great deal of renewed interest not only because the two electron temperature plasma is very common in laboratory experiments (Derfler and Simonen, 1969;Henry and Treguier, 1972) and in space (Dubouloz et al, 1991(Dubouloz et al, , 1993Pottelette et al, 1999;Berthomier et al, 2000;Singh and Lakhina, 2001), but also because of the potential importance in interpreting electrostatic component of the broadband electrostatic noise (BEN) as being solitary EA structures observed in the cusp of the terrestrial magnetosphere (Tokar and Gary, 1984;Singh and Lakhina, 2001), in the geomagnetic tail (Schriver and Ashour-Abdalla, 1989), in auroral region (Dubouloz et al, 1991(Dubouloz et al, , 1993Pottelette et al, 1999), in the numerical simulation (Lu, Wang and Dou, 2005;, and in laboratory experiment (Lefebvre, et al, 2011), etc.…”