A review of nonlinear fluid models for ion-and electron-acoustic solitons and double layers: Application to weak double layers and electrostatic solitary waves in the solar wind and the lunar wake

Shi

Geophysical Research Letters

et al. 2019

Kinetic‐scale magnetic dips (KSMDs), with a significant depression in magnetic field strength, and scale length close to and less than one proton gyroradius, were reported in the turbulent plasmas both in recent observation and numerical simulation studies. These KSMDs likely play important roles in energy conversion and dissipation. In this study, we present observations of the KSMDs that are labeled whistler mode waves, electrostatic solitary waves, and electron cyclotron waves in the magnetosheath. The observations suggest that electron temperature anisotropy or beams within KSMD structures provide free energy to generate these waves. In addition, the occurrence rates of the waves are higher in the center of the magnetic dips than at their edges, implying that the KSMDs might be the origin of various kinds of waves. We suggest that the KSMDs could provide favorable conditions for the generation of waves and transfer energy to the waves in turbulent magnetosheath plasmas.

Section: Introductionmentioning

confidence: 99%

Waves in Kinetic‐Scale Magnetic Dips: MMS Observations in the Magnetosheath

Shi

Geophysical Research Letters

et al. 2019

“…However, the EASWs observed by the spacecrafts may show an opposite amplitude-width relationship, i.e., the amplitude of soliton may enhance as its width increases. The solitons given by the Sagdeev pseudo-potential technique exhibit a different property from the KdV solitons, i.e., the amplitude of their solitons may increase or decrease with width depending upon the model and region of application [10,72]. Therefore, the Sagdeev pseudo-potential technique is a better candidate for studying the EASWs belonging to space, although, it may not necessarily show this amplitude-width relation for each plasma model.…”

Section: Sagdeev Potential Approachmentioning

confidence: 99%

Electron-Acoustic (Un)Modulated Structures in a Plasma Having (r, q)-Distributed Electrons: Solitons, Super Rogue Waves, and Breathers

et al. 2021

The propagation of electron-acoustic waves (EAWs) in an unmagnetized plasma, comprising (r,q)-distributed hot electrons, cold inertial electrons, and stationary positive ions, is investigated. Both the unmodulated and modulated EAWs, such as solitary waves, rogue waves (RWs), and breathers are discussed. The Sagdeev potential approach is employed to determine the existence domain of electron acoustic solitary structures and study the perfectly symmetric planar nonlinear unmodulated structures. Moreover, the nonlinear Schrödinger equation (NLSE) is derived and its modulated solutions, including first order RWs (Peregrine soliton), higher-order RWs (super RWs), and breathers (Akhmediev breathers and Kuznetsov–Ma soliton) are presented. The effects of plasma parameters and, in particular, the effects of spectral indices r and q, of distribution functions on the characteristics of both unmodulated and modulated EAWs, are examined in detail. In a limited cases, the (r,q) distribution is compared with Maxwellian and kappa distributions. The present investigation may be beneficial to comprehend and predict the modulated and unmodulated electron acoustic structures in laboratory and space plasmas.

“…Unfortunately, their kinetic analysis is unable to determine the origin of the slow electronhole waves since the electrons are colder than ions. The technique of Sagdeev potential had been employed by Lakhina et al [41,42] to discuss the observation of the electrostatic waves in the lunar wake and the solar wind.…”

Section: Introductionmentioning

confidence: 99%

The mechanism that drives electrostatic solitary waves to propagate in the Earth's magnetosphere and solar wind

Afify¹,

Tolba²,

Moslem³

2022

Preprint

The origin of the solitary waves in the Earth's magnetosphere and the solar wind, particularly close to the magnetic reconnection regions, is still an open question. For that purpose, we used the fluid model to obtain the mechanism behind the formation of solitary waves in space plasmas with a variety of components. Our findings reveal that at the separatrix of the magnetic reconnection in the Earth's magnetotail, the counter-ejected electron beam leads to a broadening of the pulse amplitude. While increasing the electron beam positive velocity causes a bit increase in the soliton amplitude. Moreover, we observed that the soliton profile is very sensitive to the plasma parameters like density and temperature. The calculated electric field using the current model and the measured electric field in the Earth's magnetosphere and solar wind is highlighted.