Phase space vortices in collisionless plasmas

Guio, P.; Børve, S.; Daldorff, L. K. S.; Lynov, Jens-Peter; Michelsen, Poul; Pécseli, H. L.; Rasmussen, Jens Juul; Saeki, Koichi; Trulsen, J.

doi:10.5194/npg-10-75-2003

Cited by 53 publications

(34 citation statements)

References 63 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Previous to these laboratory observations, electron holes had been launched and studied in detail in Q-machine plasmas [8][9][10] or in nonneutral plasmas [11], but no lab experiment had observed the self-consistent creation of electron holes from currentdriven turbulence. Electron holes have now also been observed and studied in detail in an experiment where turbulence was driven by an externally launched electron beam [12].…”

Section: Introductionmentioning

confidence: 99%

Observations of electron phase-space holes driven during magnetic reconnection in a laboratory plasma

et al. 2012

View full text Add to dashboard Cite

This work presents detailed experimental observations of electron phase-space holes driven during magnetic reconnection events on the Versatile Toroidal Facility. The holes are observed to travel on the order of or faster than the electron thermal speed, and are of large size scale, with diameter of order 60 Debye lengths. In addition, they have 3-D spheroidal structure with approximately unity aspect ratio. We estimate the direct anomalous resistivity due to ion interaction with the holes and find it to be too small to affect the reconnection rate; however the holes may play a role in reining in a tail of accelerated electrons, and they indicate the presence of other processes in the reconnection layer, such as electron energization and electron beam formation.

show abstract

Section: Introductionmentioning

confidence: 99%

Observations of electron phase-space holes driven during magnetic reconnection in a laboratory plasma

et al. 2012

View full text Add to dashboard Cite

show abstract

“…Vetoulis and Oppenheim [11] studied the radiation generation due to bounce resonances in electron holes. Guio et al [12,13] investigated numerically the dynamics of phase-space vortices in a collisionless plasma, as well as the generation of phase-space structures by an obstacle in a streaming plasma. Saeki and Genma [14] examined the disruption of electron holes in an electron-ion plasma.…”

Section: Introductionmentioning

confidence: 99%

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

2006

View full text Add to dashboard Cite

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...

show abstract

“…Krasovsky et al (1999) showed theoretically and by computer simulations that that electron holes perform inelastic collisions, and Vetoulis (2001) studied the radiation generation due to bounce resonances in electron holes. Guio et al (2003Guio et al ( , 2004 have studied numerically the dynamics of phase space vortices in a collisionless plasma as well as the generation of phase space structures by an obstacle in a streaming plasma. Saeki and Genma (1998) studied the disruption of electron holes in an electron-ion plasma.…”

Section: Introductionmentioning

confidence: 99%

The dynamics of electron and ion holes in a collisionless plasma

Eliasson

Shukła

2005

Nonlin. Processes Geophys.

View full text Add to dashboard Cite

Abstract. We present a review of recent analytical and numerical studies of the dynamics of electron and ion holes in a collisionless plasma. The new results are based on the class of analytic solutions which were found by Schamel more than three decades ago, and which here work as initial conditions to numerical simulations of the dynamics of ion and electron holes and their interaction with radiation and the background plasma. Our analytic and numerical studies reveal that ion holes in an electron-ion plasma can trap Langmuir waves, due the local electron density depletion associated with the negative ion hole potential. Since the scalelength of the ion holes are on a relatively small Debye scale, the trapped Langmuir waves are Landau damped. We also find that colliding ion holes accelerate electron streams by the negative ion hole potentials, and that these streams of electrons excite Langmuir waves due to a streaming instability. In our Vlasov simulation of two colliding ion holes, the holes survive the collision and after the collision, the electron distribution becomes flat-topped between the two ion holes due to the ion hole potentials which work as potential barriers for low-energy electrons. Our study of the dynamics between electron holes and the ion background reveals that standing electron holes can be accelerated by the selfcreated ion cavity owing to the positive electron hole potential. Vlasov simulations show that electron holes are repelled by ion density minima and attracted by ion density maxima. We also present an extension of Schamel's theory to relativistically hot plasmas, where the relativistic mass increase of the accelerated electrons have a dramatic effect on the electron hole, with an increase in the electron hole potential and in the width of the electron hole. A study of the interaction between electromagnetic waves with relativistic electron holes shows that electromagnetic waves can be both linearly and nonlinearly trapped in the electron hole, which widens further due to the relativistic mass increase and ponderomotive force in the oscillating electromagnetic field. The results of Correspondence to: B. Eliasson (bengt@tp4.rub.de) our simulations could be helpful to understand the nonlinear dynamics of electron and ion holes in space and laboratory plasmas.

show abstract

Phase space vortices in collisionless plasmas

Cited by 53 publications

References 63 publications

Observations of electron phase-space holes driven during magnetic reconnection in a laboratory plasma

Observations of electron phase-space holes driven during magnetic reconnection in a laboratory plasma

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

The dynamics of electron and ion holes in a collisionless plasma

Contact Info

Product

Resources

About