Turbulence generated by a gas of electron acoustic solitons

Abstract

The characteristics of the electrostatic turbulence generated by a gas of electron acoustic solitons are investigated. Electron acoustic solitons are shown to propagate in magnetized plasmas up to about 30 ø off the parallel direction without significant changes in their properties relative to the nonmagnetized case. Using the conservation properties of the Korteweg-deVries equation, the velocity distribution function Of the solitOh gas is calculated in the small-amplitude limit. For low cold to hot electron density ratios and high-mean-s. quare electric fields, a significant number of •olitons with high velocities and amplitudes is produced, implying the generation of an intense broadband electrostatic turbulence. These theoretical results are compared with the propertl'es of the broadband electrostatic noise (BEN) emissions observed by the Viking satellite in the dayside auroral zone. The electric spectra generated by the electron acoustic solitOh gases which can be derived from Viking plasma and wave observations are calculated numerically. These spectra are shown to agree with experimental data and in particular to explain the high-frequency part of BEN emissions, which lies in a range forbidden for linear electrostatic waves. 17,415

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

“…The negative potential ESWs have been interpreted in terms of ion solitary waves or solitons (Koskinen et al,904 G. S. Lakhina et al: Study of nonlinear ion-and electron-acoustic waves been commonly interpreted in terms of as Bernstein-GreeneKruskal (BGK) modes (Bernstein et al, 1957;Muschietti et al, 1999;Jovanovic and Shukla, 2000;Chen et al, 2005). Other favorite interpretations for these ESWs are based on the nonlinear evolution of a bump-on-tail instability/electron two stream instability (Omura et al, 1996;Kojima et al, 1997;Goldman et al, 1999), and electron-acoustic solitary waves (Pottelette et al, 1990;Dubouloz et al, 1991Dubouloz et al, , 1993Lakhina, 2001, 2004;Tagare et al, 2004. For a detailed discussion of various models, one can refer to Lakhina et al (2000Lakhina et al ( , 2004.…”

“…The nonlinear ion-acoustic waves in multi-species plasmas have been studied by several workers (Buti, 1980;Hudson et al, 1983;Qian et al, 1988;Bharutram and Shukla, 1986;Berthomier et al, 1998;Reddy and Lakhina, 1991;Reddy et al, 1992). The electronacoustic waves in multi-species plasmas have been discussed by Watanabe and Tanuti (1977); Gary and Tokar (1985); Hellberg (1985, 2001); Ashour-Abdalla and Okuda (1986); Pottelette et al (1990); Dubouloz et al (1991Dubouloz et al ( , 1993; Berthomier et al (2000Berthomier et al ( , 2003; ; Tagare et al (2004);Cattaert et al (2005), Kakad et al (2007) and Lakhina et al (2008).…”

“…Viking) of solitary waves which had negative potentials (Pottelette et al, 1990;Dubouloz et al, 1991Dubouloz et al, , 1993Singh and Lakhina, 2004;Tagare et al, 2004). To explain the positive potential structures, Berthomier et al (2000) introduced an electron beam in the system having cold and hot electrons.…”

Electron acoustic solitary waves with non-thermal distribution of electrons

“…It was shown that the high frequency extension of BEN in dayside auroral zone could be generated by the electronacoustic solitons passing by the satellite. Later on above study was extended to magnetized plasma to explain the turbulence generated by the gas of electron-acoustic solitons (Dubouloz et al, 1993) in dayside auroral zone. Mace et al (1991) studied the arbitrary amplitude electron-acoustic solitons in a two electron component plasma.…”

Some theoretical models for solitary structures of boundary layer waves

“…Dubouloz et al (1991aDubouloz et al ( , 1993 studied the electron-acoustic solitons (EAS) with two electroncomponents (cold and hot) and motionless ions, and showed that the high-frequency broad band electrostatic noise in the dayside auroral zone can be generated by the EAS. The effect of upward propagating electron beams that are commonly observed in the dayside auroral zone was not taken into consideration.…”