Nonlinear Model for Coherent Electric Field Structures in the Magnetosphere

Jovanović, D.; Shukła, P. K.

doi:10.1103/physrevlett.84.4373

Cited by 56 publications

(43 citation statements)

References 13 publications

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“…A new pseudo-3D electron hole in a non-uniform magnetized plasma is possible when the low-frequency ion dynamics is taken into account [139]. This structure is characterized as 3D electron holes coupled with hydrodynamic vortices in a quasi-neutral non-uniform magnetoplasma, and can provide a possible theoretical explanation for the POLAR and FAST satellite observations of coherent structures characterized by bipolar spikes of the parallel electric field and large perpendicular ion kinetic energies.…”

Section: Electron Holes In a Non-uniform Magnetized Plasma Involving mentioning

confidence: 99%

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Formation and dynamics of coherent structures involving phase-space vortices in plasmas

2006

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We present a comprehensive review of recent theoretical and numerical studies of the formation and dynamics of electron and ion holes in a collisionless plasma. The electron hole is characterized by a localized positive potential in which a population of electrons is trapped, and a depletion of the electron number density, while the ion hole is associated with localized negative potential in which a population of ions is trapped and a depletion of both the ion and electron densities occur. We present conditions for the existence of quasi-stationary electron and ion holes in unmagnetized and magnetized electron-ion plasmas, as well as in an unmagnetized pair-ion plasma. An interesting aspect is the dynamic interactions between ion and electron holes and the surrounding plasma. The dynamics is investigated by means of numerical simulations in which analytical solutions of quasistationary electron and ion holes are used as initial conditions. Our Vlasov simulations of two colliding ion holes reveal the acceleration of electrons and a modification of the initially Maxwellian electron distribution function by the ion hole potentials, which work as barriers for the electrons. A secondary effect is the excitation of high-frequency plasma waves by the streams of electrons. On the other hand, we find that electron holes show an interesting dynamics in the presence of mobile ions. Since electron holes are associated with a positive electrostatic potential, they repel positively charged ions. Numerical simulations of electron holes in a plasma with mobile ions exhibit that the electron holes are, in general, attracted by ion density maxima and repelled by ion density minima. Therefore, standing electron holes can be accelerated by the self-created ion cavities. In a pair plasma, both the temperatures and masses of the positively and negatively charged particles are assumed equal, and therefore one must treat both species with a kinetic theory on an equal footing. Accordingly, a phase-space hole in one of the species is associated with reflected particles in the opposite species. Here standing solitary large-amplitude holes are not allowed, but they must have a propagation speed close to the thermal speed of the particles. We discuss extensions of the existing non-relativistic theories for the electron and ion holes in two directions. First, we describe a fully nonlinear kinetic theory for relativistic electron holes (REHs) in an unmagnetized plasma, and show that the REHs have amplitudes and widths much larger than their non-relativistic counterparts. Second, we extend the weakly nonlinear theories for the electron and ion holes to include the effects of the external magnetic field and the plasma inhomogeneity. The presence of the external magnetic field gives rise to the electron and ion hole structures which have differential scale sizes along and across the magnetic field direction. Consideration of the density inhomogeneity in a magnetized plasma with non-isothermal electron distribution function provides the p...

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Section: Electron Holes In a Non-uniform Magnetized Plasma Involving mentioning

confidence: 99%

“…[139], but due to its higher characteristic frequency it does not involve any ion dynamics. Its parallel spatial scale is typically 1/ tan times larger than the perpendicular scale.…”

Section: Drift-kinetic Theory Of Electron Holesmentioning

confidence: 99%

Formation and dynamics of coherent structures involving phase-space vortices in plasmas

2006

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“…By redoing the calculations, we can easily see that it is not a new type but the simple waves with a longer period for peaks to occur). Their studies were followed by, e.g., Nakamura & Sugai (1996); Chatterjee & Roychoudhury (1997); Das et al (2000); Jovanovic & Shukla (2000); Mamun & Shukla (2002). Particularly, Reddy et al (2002); Bharuthram et al (2002); Ma & Hirose (2009) not only verified that the nonlinear structures originate from a coupling between the IC and IA modes, but also obtained the three waveforms reported firstly by Temerin et al (1979).…”

Section: Introductionmentioning

confidence: 99%

Nonlinear ion-acoustic (IA) waves driven in a cylindrically symmetric flow

John

2010

Astrophys Space Sci

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By employing a self-similar, two-fluid MHD model in a cylindrical geometry, we study the features of nonlinear ion-acoustic (IA) waves which propagate in the direction of external magnetic field lines in space plasmas. Numerical calculations not only expose the well-known three shapes of nonlinear structures (sinusoidal, sawtooth, and spiky or bipolar) which are observed by numerous satellites and simulated by models in a Cartesian geometry, but also illustrate new results, such as, two reversely propagating nonlinear waves, density dips and humps, diverging and converging electric shocks, etc. A case study on Cluster satellite data is also introduced.

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“…The ESWs associated with the ion beam regions of the auroral zone usually have negative potentials and propagate at velocities of the order of ion-acoustic or beam speed (Temerin et al, 1982;Boström et al, 1988;Koskinen et al, 1990). 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.…”

Section: Introductionmentioning

confidence: 99%

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

Lakhina

Singh

Kakad

et al. 2008

Nonlin. Processes Geophys.

102

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Abstract. Large amplitude ion-acoustic and electronacoustic waves in an unmagnetized multi-component plasma system consisting of cold background electrons and ions, a hot electron beam and a hot ion beam are studied using Sagdeev pseudo-potential technique. Three types of solitary waves, namely, slow ion-acoustic, ion-acoustic and electron-acoustic solitons are found provided the Mach numbers exceed the critical values. The slow ion-acoustic solitons have the smallest critical Mach numbers, whereas the electron-acoustic solitons have the largest critical Mach numbers. For the plasma parameters considered here, both type of ion-acoustic solitons have positive potential whereas the electron-acoustic solitons can have either positive or negative potential depending on the fractional number density of the cold electrons relative to that of the ions (or total electrons) number density. For a fixed Mach number, increases in the beam speeds of either hot electrons or hot ions can lead to reduction in the amplitudes of the ion-and electron-acoustic solitons. However, the presence of hot electron and hot ion beams have no effect on the amplitudes of slow ion-acoustic modes. Possible application of this model to the electrostatic solitary waves (ESWs) observed in the plasma sheet boundary layer is discussed.

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Nonlinear Model for Coherent Electric Field Structures in the Magnetosphere

Cited by 56 publications

References 13 publications

Formation and dynamics of coherent structures involving phase-space vortices in plasmas

Formation and dynamics of coherent structures involving phase-space vortices in plasmas

Nonlinear ion-acoustic (IA) waves driven in a cylindrically symmetric flow

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

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