Electron beam-associated symmetric electrostatic solitary waves on the separatrix of magnetic reconnection: multi-spacecraft analysis

Li, Shiyou; Zhang, Shifeng; Cai, Hong; Yang, Huabo

doi:10.1186/s40623-015-0256-5

Cited by 8 publications

(4 citation statements)

References 52 publications

(79 reference statements)

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“…This is likely due to the higher instrumental resolution required. 26,[73][74][75] Perhaps, current MMS observations will provide more information about them as already about field-aligned currents near the PSBL. 76 In the PSBL a strong broadband electrostatic noise (BEN) is generated from the lower hybrid frequency Ω LH 77 up to the electron plasma frequency.…”

Section: Introductionmentioning

confidence: 99%

Non-Maxwellian electron distribution functions due to self-generated turbulence in collisionless guide-field reconnection

Muñoz

Büchner

2016

Physics of Plasmas

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Non-Maxwellian electron velocity space distribution functions (EVDF) are useful signatures of plasma conditions and non-local consequences of collisionless magnetic reconnection. In the past, EVDFs were obtained mainly for antiparallel reconnection and under the influence of weak guide-fields in the direction perpendicular to the reconnection plane. EVDFs are, however, not well known, yet, for oblique (or component-) reconnection in case and in dependence on stronger guide-magnetic fields and for the exhaust (outflow) region of reconnection away from the diffusion region. In view of the multi-spacecraft Magnetospheric Multiscale Mission (MMS), we derived the non-Maxwellian EVDFs of collisionless magnetic reconnection in dependence on the guide-field strength b g from small (b g ≈ 0) to very strong (b g = 8) guide-fields, taking into account the feedback of the self-generated turbulence. For this sake, we carried out 2.5D fully-kinetic Particle-in-Cell simulations using the ACRONYM code. We obtained anisotropic EVDFs and electron beams propagating along the separatrices as well as in the exhaust region of reconnection. The beams are anisotropic with a higher temperature in the direction perpendicular rather than parallel to the local magnetic field. The beams propagate in the direction opposite to the background electrons and cause instabilities. We also obtained the guide-field dependence of the relative electron-beam drift speed, threshold and properties of the resulting streaming instabilities including the strongly non-linear saturation of the self-generated plasma turbulence. This turbulence and its non-linear feedback cause non-adiabatic parallel electron acceleration. We further obtained the resulting EVDFs due to the non-linear feedback of the saturated self-generated turbulence near the separatrices and in the exhaust region of reconnection in dependence on the guide field strength. We found that the influence of the self-generated plasma turbulence leads well beyond the limits of the quasi-linear approximation, to the creation of phase space holes and an isotropizing pitch-angle scattering. EVDFs obtained by this way can be used for diagnosing collisionless reconnection by using the multi-spacecraft observations carried out by the MMS mission.

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Section: Introductionmentioning

confidence: 99%

Non-Maxwellian electron distribution functions due to self-generated turbulence in collisionless guide-field reconnection

Muñoz

Büchner

2016

Physics of Plasmas

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“…They noted that this is the first report of “such a large number of ESWs in a single magnetic reconnection event.” The ESWs were observed, “around the magnetic null‐pairs within the magnetic reconnection ion diffusion region.” They performed “single‐event‐based statistical analysis of the characteristics of the ESWs around magnetic null‐pairs.” They speculated, “based on the statistical result,” that “the two‐stream instability originating from the magnetic null and traveling outward along the PSBL is the candidate mechanism of the large number of observed ESWs.” In another ESW study, Li et al. (2015) provided evidence “of electron beam‐associated symmetric bipolar” ESWs on the current sheet‐side of the separatrix of the magnetic reconnection in the near‐Earth magnetotail. The multi‐spacecraft comparisons led to the conclusion that ESWs were “strongly associated with the cold electron beams of a few hundreds of EV (0.4–1 keV) antiparallel to the local magnetic field which is consistent with the bump‐on tail instability.” However, the electron beam is directed inward but the ESWs were traveling outward, suggesting it is not clear what the relationship is between the two.…”

Section: Review Of Cluster Esw Resultsmentioning

confidence: 99%

“…They speculated, "based on the statistical result," that "the two-stream instability originating from the magnetic null and traveling outward along the PSBL is the candidate mechanism of the large number of observed ESWs." In another ESW study, Li et al (2015) provided evidence "of electron beam-associated symmetric bipolar" ESWs on the current sheet-side of the separatrix of the magnetic reconnection in the near-Earth magnetotail. The multi-spacecraft comparisons led to the conclusion that ESWs were "strongly associated with the cold electron beams of a few hundreds of EV (0.4-1 keV) antiparallel to the local magnetic field which is consistent with the bump-on tail instability."…”

Section: Esws Associated With Magnetic Reconnectionmentioning

confidence: 99%

A Review of Electrostatic Solitary Wave Research From the Cluster Mission

Pickett

2021

JGR Space Physics

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A review of the advancements in the knowledge of electrostatic solitary waves (ESWs) made with data obtained by the four satellite Cluster mission, after 20 years in orbit, is presented. ESWs are nonlinear solitary waves or structures observed in high time resolution waveform data. The ESW pulses are the wave data representation of electron or ion phase‐space holes, or density/acoustic structures, and are observed throughout the Cluster orbit, particularly at boundary layers, in turbulent plasmas, and wherever there is mixing of plasmas, such as in the magnetotail with the onset of a super‐substorm. Much of the research reviewed here involves ESWs involved in the magnetic reconnection processes of Earth, with their mapping across the separatrix region. One of the major advancements in ESW knowledge came from investigating propagation from one spacecraft to another, thus addressing the issue of lifetime and stability of these structures which cannot be adequately addressed with single spacecraft propagation studies. Knowing how stable the ESWs are can help determine their generation mechanism, which was also addressed in many of the papers discussed herein through observations and theory. The ESWs were found to be generated through a mix of instabilities and processes, namely two‐stream, Buneman, bump‐on‐tail, electron‐ion, beam‐plasma, electron and ion acoustic instabilities, and out of turbulence.

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“…In the most straightforward case, electron gyro‐radii of inflow and outflow populations are expected to overlap at the separatrix, leading to a narrow region unstable to counterstreaming modes, growing waves and electron phase‐space holes which are frequently seen in simulations and in situ observations by spacecraft in Earth's magnetosphere (Cattell et al., 2005; Drake et al., 2003; K. Fujimoto, 2014; Li et al., 2015). Separatrices often host additional rippling features due to the lower hybrid drift instability (LHDI; Price et al., 2016; Yoon et al., 2008), which may be capable of enhancing the mixing process (Davidson & Gladd, 1975; Le et al., 2018).…”

Section: Introductionmentioning

confidence: 99%

Wave Activity in a Dynamically Evolving Reconnection Separatrix

et al. 2021

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Magnetic reconnection's overall structure consists of a region of slow advective inflow and rapid outflow energized by the release of magnetic tension. Inflowing electrons are initially frozen-in to the magnetic field, confined to a narrow flux tube which expands into the electron diffusion region (EDR), causing acceleration of field-aligned electron beams. The nature of the parallel electric field required to accelerate inflowing electrons remains unclear, and its study is made difficult by the strong waves frequently observed at the separatrix which divides the inflow and outflow. In this region, a combination of magnetic shear, pressure gradient, and counterstreaming plasma flows give rise to numerous plasma instabilities.In the most straightforward case, electron gyro-radii of inflow and outflow populations are expected to overlap at the separatrix, leading to a narrow region unstable to counterstreaming modes, growing waves and electron phase-space holes which are frequently seen in simulations and in situ observations by spacecraft

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Electron beam-associated symmetric electrostatic solitary waves on the separatrix of magnetic reconnection: multi-spacecraft analysis

Cited by 8 publications

References 52 publications

Non-Maxwellian electron distribution functions due to self-generated turbulence in collisionless guide-field reconnection

Non-Maxwellian electron distribution functions due to self-generated turbulence in collisionless guide-field reconnection

A Review of Electrostatic Solitary Wave Research From the Cluster Mission

Wave Activity in a Dynamically Evolving Reconnection Separatrix

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