Magnetic depression and electron transport in an ion-scale flux rope associated with Kelvin–Helmholtz waves

Tang, Binbin; Li, Wenya; Wang, Chi; Dai, Lei; Khotyaintsev, Yuri V.; Lindqvist, Per‐Arne; Ergun, R. E.; Contel, O. Le; Pollock, C. J.; Russell, C. T.; Burch, J. L.

doi:10.5194/angeo-36-879-2018

Cited by 12 publications

(16 citation statements)

References 47 publications

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“…The current density increased within each of the FTEs and had many fine structures in all three directions (Figures i, i, i, and t), consistent with the previous observation of the filamentary currents (Eastwood et al, ; Tang et al, ; Wang, Nakamura, et al, ). The ratio of J ⊥ / J ∥ was very large in the draping regions of the FTEs and mostly close to 0 in the core regions of the FTEs (Figures j, j, j, and u).…”

Section: Database and Observationsupporting

confidence: 89%

Anisotropic Electron Distributions and Whistler Waves in a Series of the Flux Transfer Events at the Magnetopause

Wang

Yao

et al. 2019

JGR Space Physics

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With the measurements of the Magnetospheric Multiscale mission at the magnetopause, we investigated the electron distribution and the whistler waves associated with a series of six ion-scale flux transfer events (FTEs). Based on the magnetic field signature, each FTE can be divided into the core region and the draping region. In the draping regions of the most FTEs, the low-energy electrons displayed a bidirectional field-aligned distribution. The medium-energy electrons showed a field-aligned or beam distribution in the leading part, while a pancake distribution was presented for the electrons in the trailing part of the draping region, which has never been reported previously. The close correlation between the pancake distribution and the compression of the localized magnetic field suggests that the pancake distribution may be due to the betatron acceleration. The whistler waves associated with the FTEs were observed and categorized into the lower and upper bands according to the frequency range. The lower band whistler waves propagated in variable directions and therefore could be generated locally. The trailing part of the draping region with the electron pancake distribution was considered to be one possible source region. On the contrary, the upper band whistler waves were all found in the core region and propagated antiparallel to the magnetic field and therefore originated from the same source region. The observations confirmed that the FTEs are important channels for the mass and wave transport between the magnetosheath and the inner magnetosphere, and the electron dynamics can be modified during the FTE evolution.

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Section: Database and Observationsupporting

confidence: 89%

Anisotropic Electron Distributions and Whistler Waves in a Series of the Flux Transfer Events at the Magnetopause

Wang

Yao

et al. 2019

JGR Space Physics

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“…Figure 5 shows MMS survey data for the two additional events, given in the same format as Figure 1. The September 27, 2016 event was first reported by (Tang et al, 2018). The interval from 19:50-20:06 UT, while shorter in duration than the September 8, 2015 observations, shows similar activity.…”

Section: Kelvin-helmholtz Events Further Down the Flanksmentioning

confidence: 80%

“…From Figure 5, there are some immediate similarities with the other events. First, between 16:50 and 19:00 UT, there were periodic boundary crossings apparent in the ion and electron spectra and temperature, as well as the plasma density, with a dominant periodicity of 230 °s, which is longer than the terminator event (∼45 °s) (Tang et al, 2018) One difference is that the reductions in the anti-sunward flow are even more significant than in the other two events. The challenge in analyzing this event is that immediately after this event is that immediately after the plotted interval in Figure 5, the MMS exited fast survey mode, and therefore the complete crossing into the magnetospheric side of the boundary was not recorded.…”

Section: Kelvin-helmholtz Events Further Down the Flanksmentioning

confidence: 99%

“…There was also evidence for the mixing of multiple particle populations in the middle of the vortices, leading to strong ion-acoustic-like parallel electric field fluctuations that did not appear to be current-driven (Wilder et al, 2016a;Wilder et al, 2020). The study of another KHI event, on September 27, 2016, suggested that lower hybrid waves that arise during the instability could also facilitate the diffusion of plasma across the flank magnetopause (Tang et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

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The Occurrence and Prevalence of Time Domain Structures in the Kelvin-Helmholtz Instability at Different Positions Along the Earth’s Magnetospheric Flanks

Wilder

Ergun

Gove

et al. 2021

Front. Astron. Space Sci.

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The Kelvin-Helmholtz instability (KHI) is thought to be an important driver for mass, momentum, and energy transfer between the solar wind and magnetosphere. This can occur through global-scale “viscous-like” interactions, as well as through local kinetic processes such as magnetic reconnection and turbulence. An important aspect of these kinetic processes for the dynamics of particles is the electric field parallel to the background magnetic field. Parallel electric field structures that can occur in the KHI include the reconnection electric field of high guide field reconnection, large amplitude ion acoustic waves, as well as time domain structures (TDS) such as double layers and electrostatic solitary waves. In this study, we present a survey of parallel electric field structures observed during three Kelvin Helmholtz events observed by NASA’s Magnetospheric Multiscale (MMS), each at different positions along the magnetosphere’s dusk flank. Using data from MMS’s on-board solitary wave detector (SWD) algorithm, we statistically investigate the occurrence of TDS within the KHI events. We find that early in the KHI development, TDS typically occur in regions with strong field-aligned currents (FACs) on the magnetospheric side of the vortices. Further down the flanks, as the vortices become more rolled up, the prevalence of large electric currents decreases, as well as the prevalence of SWDs. These results suggest that as the instability develops and vortices grow in size along the flanks, kinetic-scale activity becomes less prevalent.

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“…They report that the frequency range inside (0.5F ce ∼ F ce ) is higher than outside (0.1F ce ∼ F ce ), where F ce is electron cyclotron frequency. Lowfrequency waves such as lower-hybrid drift waves (LHDI) and kinetic Alfven waves (KAW) were also studied by Tang et al [8,9]. A variety of waves associated with the flux ropes were intensively studied by Øieroset et al [10], showing an entire picture of wave distribution near the flux rope.…”

Section: Introductionmentioning

confidence: 99%

Waves Generated by Electron Beam in a Crater-Shaped Flux Rope

et al. 2021

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Understanding the nature and characteristics of high-frequency waves inside a flux rope may be important as the wave-particle interaction is important for charged-particle energization and the ensuing dissipation process. We analyze waves generated by an electron beam in a crater-shaped magnetic flux rope observed by MMS spacecraft on the dawnside tailward magnetopause. In this MMS observation, a depression of magnetic field, or a crater, of ∼100 km is located at the center of the magnetic flux rope of ∼650 km. There exist parallel and perpendicular electrostatic wave modes inside the depression of the magnetic field at the center of the flux rope, and they are distinguished by their locations and frequencies. The parallel mode exists at the center of the magnetic depression and its power spectrum peaks below Fce (electron cyclotron frequency). In contrast, the perpendicular mode exists in the outer region associated with the magnetic depression, and its power spectrum peaks near Fce. The linear analysis of kinetic instability using a generalized dispersion solver shows that the parallel mode can be generated by the electron beam of 5,000 km/s. They can thermalize electrons ≲100 eV effectively. However, the generation mechanism of the perpendicular mode is not clear yet, which requires further study.

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Magnetic depression and electron transport in an ion-scale flux rope associated with Kelvin–Helmholtz waves

Cited by 12 publications

References 47 publications

Anisotropic Electron Distributions and Whistler Waves in a Series of the Flux Transfer Events at the Magnetopause

Anisotropic Electron Distributions and Whistler Waves in a Series of the Flux Transfer Events at the Magnetopause

The Occurrence and Prevalence of Time Domain Structures in the Kelvin-Helmholtz Instability at Different Positions Along the Earth’s Magnetospheric Flanks

Waves Generated by Electron Beam in a Crater-Shaped Flux Rope

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