Spontaneous Emission of Alfvénic Branch Oscillations From a Strong Inhomogeneous Plasma Flow

Liu, Yu; Lei, Jiuhou; Yu, Peng; Liu, Pengfei; Ling, Yangrong; Zhang, Zhiqing Philippe; Cao, Jinxiang

doi:10.1002/2017gl075611

Cited by 13 publications

(8 citation statements)

References 42 publications

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“…The mode number m = 0.74 × 7 ∼ agrees well with previous experimental results for KH modes, which have typically m ∼ 3,4,5 (Jassby & Perkins, ). This mode can be identified as the collisionless KHI, which has been studied previously (Liu et al, ). However, the collisionless mode was dissipated by the ion‐neutral collisions when the injected flow exceeds a threshold (50 sccm, ν i n = 8 kHz) and a new wave mode subsequently was excited (see Figure a).…”

Section: Resultsmentioning

confidence: 87%

“…The Kelvin‐Helmholtz instability (KHI) is one of the shear‐driven modes (Peñano & Ganguli, ), and it is frequently observed in the solar corona, solar wind, magnetopause, inner magnetosphere, and ionosphere of the Earth, planets, and comets (Fairfield et al, ; Johnson et al, ; Nykyri & Otto, ; Phan & Paschmann, ; Soler et al, ; Terada et al, ). In the magnetospheric plasma, the KHI is considered to play an important role in the cross scale transport of energies and particles from the solar wind into the magnetosphere (Hasegawa et al, ; Liu et al, ; Moore et al, ). In the ionospheric plasma, theory predicted that the KHI can nonlinearly steepen and further give rise to highly stressed regions of strongly sheared flows.…”

Section: Introductionmentioning

confidence: 99%

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Laboratory Excitation of the Kelvin‐Helmholtz Instability in an Ionospheric‐Like Plasma

Liu

Lei

et al. 2018

Geophysical Research Letters

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In the work, laboratory experiments were designed to simulate the collisional plasma environment of the ionosphere. Neutral gas was injected to increase the ion-neutral collisions, and the ambient plasma subsequently transforms from the magnetospheric-like collisionless plasma to the ionospheric-like collisional one. In the collisionless plasma, the classical electrostatic Kelvin-Helmholtz instability (KHI) was generated using an interpenetrating plasma method. However, the collisionless KHI was dissipated in the collisional plasma and subsequently a new wave mode was excited. The mode was identified as the collisional KHI by comparing the experimental results with the theoretical wave dispersion relation. The result indicates that the KHI can be excited in the ionospheric-like collisional plasma, which could be applied to understand the generation mechanism of the ionospheric irregularities by the bottomside sheared flow.Plain Language Summary Ionospheric irregularities, in the form of density spikes and cavities, are universal in the ionosphere from low to high latitudes. The ionospheric irregularities have a significant impact on satellite radio communications. The Kelvin-Helmholtz instability (KHI) was considered to play a significant role in the generation of the ionospheric irregularities. However, a key issue is that the generation of KHI in a collisional plasma has not been experimentally verified. In the work, laboratory experiments were conducted to simulate the collisional environment of the ionosphere. The result suggests that the shear-driven KHIs can be generated in an ionospheric-like collisional plasma. Through our experimental work, the theoretical mechanism can be more confidently applied to explain the excitation of ionospheric irregularities.

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Section: Resultsmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Laboratory Excitation of the Kelvin‐Helmholtz Instability in an Ionospheric‐Like Plasma

Liu

Lei

et al. 2018

Geophysical Research Letters

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“…In this scenario, the increased flux tube interchange can cause the plasma density distribution to become convectively unstable, thereby leading to the growth of small‐scale density irregularities in the plasmasphere. Kelvin‐Helmholtz (KH) instability (Chandrasekhar, 1961) excited by the velocity shear of the plasma (Liu et al., 2018 and references therein), can also be a triggering factor for generating these small‐scale density undulations near the plasmapause boundary.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Small‐Scale Electron Density Irregularities Observed by the Arase and Van Allen Probes Satellites Inside and Outside the Plasmasphere

et al. 2021

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The plasmasphere is the innermost region of the Earth's magnetosphere, which is filled with cold (low energy ∼1-10 electron volt (eV) and dense (10-10 4 cm −3)) plasma of ionospheric origin trapped to the Earth's magnetic field, forming a thermal plasma cloud encircling the Earth (Darrouzet et al., 2009b; Lemaire et al., 1998). Outside the plasmasphere, the plasma characteristics change abruptly to tenuous (1 cm −3), hot (high energy ∼100 eV) plasma. The boundary that separates this outer region of the highly energized, low-density plasma from the plasmasphere, is called plasmapause. The plasma motions in the inner magnetosphere are dominated by large scale electric fields. The corotation electric field enforces the corotation of cold plasma near the Earth, and the magnetospheric convection electric field (generated by the interaction between the solar wind and the magnetosphere) causes the loss of cold plasma outside the plasmasphere. The convection electric field, being a key factor for the formation of the plasmapause (Pierrard et al., 2008), the location and sharpness of the plasmapause vary with

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“…Several possible mechanisms for the transport of solar wind plasma, momentum, and energy across the magnetopause under northward IMF have been proposed (e.g., Gou et al, ; Shi et al, ; Song & Russell, ; Terasawa et al, ). The Kelvin‐Helmholtz instability (KHI), excited by velocity shear near the magnetopause, is one of the possible mechanisms of plasma entry (e.g., Chandrasekhar, ; Fairfield et al, ; Hasegawa et al, ; Liu et al, ). Besides the energy transport into the magnetosphere, KHI along the magnetopause also excites ultra low frequency (ULF) waves in the magnetosphere (e.g., Chen & Hasegawa, ; Rae et al, ; Wang, Thorne, et al, ), which play an important role in many dynamic processes, such as auroral activity and transport of radiation belt electrons.…”

Section: Introductionmentioning

confidence: 99%

Observations of Kelvin‐Helmholtz Waves in the Earth's Magnetotail Near the Lunar Orbit

et al. 2018

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Kelvin-Helmholtz waves (KHWs), which have been widely observed at the magnetopause in the region near the Earth, play an essential role in the transport of solar wind plasma and energy into the magnetosphere under dominantly northward interplanetary magnetic field (IMF) conditions. In this study, we present simultaneous observations of KHWs under the northward IMF observed by both the Acceleration, Reconnection, Turbulence, and Electrodynamics of Moon's Interaction with the Sun (ARTEMIS) spacecraft in the Earth's magnetotail around the lunar orbit (at X~À50R E , Y~30R E , dusk side) and the Geotail in the near-Earth space (at X~À5R E , Y~À10R E , dawn side). The KHWs are quantitatively characterized by their dominant period, phase velocity, and wavelength, utilizing wavelet analysis and an approximation of their center-of-mass velocity. Our results suggest that the phase velocity and spatial scale of KHWs may increase as they propagate along the boundary layer toward the tail. Alternatively, the differences between the ARTEMIS and Geotail observations may indicate the possibility of dawn-dusk asymmetry in the excited KHWs in this study. Our results strongly evidence the existence of the development of KHWs in terms of their wave frequency and scale size in the magnetotail and provide insight to the time evolution of KHWs along the magnetopause.

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Spontaneous Emission of Alfvénic Branch Oscillations From a Strong Inhomogeneous Plasma Flow

Cited by 13 publications

References 42 publications

Laboratory Excitation of the Kelvin‐Helmholtz Instability in an Ionospheric‐Like Plasma

Laboratory Excitation of the Kelvin‐Helmholtz Instability in an Ionospheric‐Like Plasma

Investigation of Small‐Scale Electron Density Irregularities Observed by the Arase and Van Allen Probes Satellites Inside and Outside the Plasmasphere

Observations of Kelvin‐Helmholtz Waves in the Earth's Magnetotail Near the Lunar Orbit

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