Electron Phase Space Holes as Localized BGK Solutions

Turikov, V. A.

doi:10.1088/0031-8949/30/1/015

Cited by 94 publications

(90 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The pulse has a symmetric positive potential with dipolar electric field and a charge density which is positive at the center and negative near the edges. These properties are consistent with a Bernstein-Greene-Kruskal electron hole [1]. The shaded area corresponds to a theoretically inaccessible region [11].…”

Section: Electrostatic Solitary Structures Identified Assupporting

confidence: 75%

“…In particular the plasma in which the solitary waves propagate is likely warmer due to the interaction with the beam, making the structure velocities closer to the actual thermal speed. Indeed it was predicted that electron holes faster than 2v T e are unstable [1] and are therefore unlikely to be observed. Normalization questions apart, electron hole sizes significantly larger than λ De are theoretically allowed.…”

Section: Electrostatic Solitary Structures Identified Asmentioning

confidence: 99%

See 1 more Smart Citation

Laboratory Measurements of Electrostatic Solitary Structures Generated by Beam Injection

et al. 2010

View full text Add to dashboard Cite

Electrostatic solitary structures are generated by injection of a suprathermal electron beam parallel to the magnetic field in a laboratory plasma. Electric microprobes with tips smaller than the Debye length (λDe) enabled the measurement of positive potential pulses with half-widths 4 to 25λDe and velocities 1 to 3 times the background electron thermal speed. Nonlinear wave packets of similar velocities and scales are also observed, indicating that the two descend from the same mode which is consistent with the electrostatic whistler mode and result from an instability likely to be driven by field-aligned currents. [4,5]. Electron holes were also recently detected in a laboratory magnetic reconnection experiment [6]. Electron holes can be generated by energetic streaming electrons and are thought to play an important role in scattering these electrons. However, although these small-scale (one to tens of Debye lengths, λ De ) solitary structures seem ubiquitous in key regions of space their exact origin often remains unclear. In the laboratory, experiments dedicated to electron holes were carried out in a strongly magnetized Q-machine [7]. These holes were generated by a voltage pulse and had sizes comparable to the plasma column radius, making comparison with holes observed in space difficult.This Letter reports measurements of electrostatic solitary waves generated by an electron beam injected into a magnetized low-β plasma column much larger than the structure scales (Fig. 1). The experiment was conducted at the upgraded Large Plasma Device (LAPD) [8] at the University of California, Los Angeles. The helium plasma column has a 60 cm diameter, is 17.1 m long and pulsed at 1 Hz with pulses lasting several milliseconds (Fig. 1a) An electron beam 0.4 to 1 cm in diameter is injected from a 3 mm diameter LaB6 crystal source for about 140 µs along the axis of the column in the afterglow phase, between 50 and 150 ms after the end of the discharge pulse. The beam density 5 cm from the source is approximately 25% of the background electron density. The magnetic field strength, plasma density and beam voltage can be changed from experiment to experiment. The range of the main plasma parameters is summarized in

show abstract

Section: Electrostatic Solitary Structures Identified Assupporting

confidence: 75%

Section: Electrostatic Solitary Structures Identified Asmentioning

confidence: 99%

Laboratory Measurements of Electrostatic Solitary Structures Generated by Beam Injection

et al. 2010

View full text Add to dashboard Cite

show abstract

“…Electron phase space holes have been long studied as examples of nonlinear solitary structures, either as solutions of the unmagnetized Vlasov-Maxwell system (BGK waves), 12 the Vlasov-Poisson system, 13 or using fluid models. 14,15 These structures depend for their existence on particle trapping in the electrostatic potential of the wave. A model of magnetic structure associated with electron phase space holes has been proposed by Treumann and Baumjohann, 16 in which an azimuthal electron current is driven by the E Â B drift, enhancing the magnetic field at the center and reducing it outside.…”

Section: Introductionmentioning

confidence: 99%

Electron vortex magnetic holes: A nonlinear coherent plasma structure

et al. 2015

View full text Add to dashboard Cite

We report the properties of a novel type of sub-proton scale magnetic hole found in two dimensional particle-in-cell simulations of decaying turbulence with a guide field. The simulations were performed with a realistic value for ion to electron mass ratio. These structures, electron vortex magnetic holes (EVMHs), have circular cross-section. The magnetic field depression is associated with a diamagnetic azimuthal current provided by a population of trapped electrons in petal-like orbits. The trapped electron population provides a mean azimuthal velocity and since trapping preferentially selects high pitch angles, a perpendicular temperature anisotropy. The structures arise out of initial perturbations in the course of the turbulent evolution of the plasma, and are stable over at least 100 electron gyroperiods. We have verified the model for the EVMH by carrying out test particle and PIC simulations of isolated structures in a uniform plasma. It is found that (quasi-)stable structures can be formed provided that there is some initial perpendicular temperature anisotropy at the structure location. The properties of these structures (scale size, trapped population, etc.) are able to explain the observed properties of magnetic holes in the terrestrial plasma sheet. EVMHs may also contribute to turbulence properties, such as intermittency, at short scale lengths in other astrophysical plasmas. V C 2015 AIP Publishing LLC.

show abstract

“…The trapped particles play crucial roles in these models (Bernstein et al, 1957;Turikov, 1984). The waveform observations by the plasma wave instrument on board the Geotail spacecraft have shown that broad band electrostatic noise (BEN) consists of a series of bipolar solitary pulses .…”

Section: Bgk Modes/phase Space Holesmentioning

confidence: 99%

Some theoretical models for solitary structures of boundary layer waves

Lakhina

Tsurutani

Singh

et al. 2003

Nonlin. Processes Geophys.

View full text Add to dashboard Cite

Abstract. Solitary electrostatic structures have been observed in and around auroral zone field lines at various altitudes ranging from close to the ionosphere, to the magnetopause low-latitude boundary layer (LLBL) and cusp on the dayside, and to the plasma sheet boundary layer on the nightside. In this review, various models based on solitons/double layers and BGK modes or phase space holes are discussed in order to explain the characteristics of these solitary structures.

show abstract

Electron Phase Space Holes as Localized BGK Solutions

Cited by 94 publications

References 9 publications

Laboratory Measurements of Electrostatic Solitary Structures Generated by Beam Injection

Laboratory Measurements of Electrostatic Solitary Structures Generated by Beam Injection

Electron vortex magnetic holes: A nonlinear coherent plasma structure

Some theoretical models for solitary structures of boundary layer waves

Contact Info

Product

Resources

About