Design and construction of Keda Space Plasma Experiment (KSPEX) for the investigation of the boundary layer processes of ionospheric depletions

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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“…The experiment was performed using the Keda Space Plasma EXperiment (KSPEX), USTC (Liu et al, ). The experimental processes include two stages.…”

Section: Methodsmentioning

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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“…The experiment was performed using the Keda Space Plasma EXperiment (KSPEX) which is a linear magnetized plasma machine with a vacuum chamber 2.73 m in length and 0.5 m in diameter [ Liu et al , ]. The vacuum chamber is surrounded by six electromagnet coils that can produce a uniform axial magnetic field with field strength up to 1000 G. As shown in Figure , the argon plasma was generated by two kinds of plasma sources [ Amatucci et al , ; DuBois et al , ].…”

Section: Methodsmentioning

confidence: 99%

Laboratory generation of broadband ELF waves by inhomogeneous plasma flow

Liu

Lei

et al. 2017

Geophysical Research Letters

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Transversely accelerated ions and the associated heating of the high‐latitude ionosphere have been attributed to broadband extremely low frequency (BBELF) turbulence. Controlled laboratory tests of the hypotheses on the formation mechanism of BBELF waves have involved only a few examples, e.g., current‐driven and shear‐driven instabilities. In this work, electrostatic fluctuations in the ion cyclotron frequency range have been excited by inhomogeneous energy‐density‐driven instability (IEDDI). This was achieved using the interpenetrating plasma method with a much larger electric field scale size LE comparable to the ion gyroradius ρi, which was challenging earlier because of plasma conditions. The peak frequency of the IEDDI spectrum falls as low as ω≈0.3ωci, where ωci is ion cyclotron frequency. This is an interesting result because the previous attempts could not produce such low‐frequency IEDDI, although it was known theoretically to be possible. The observations made by FAST, Freja, and Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites might be explainable in terms of the reported experimental results.

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“…The experiment was performed using the Keda Space Plasma EXperiment (KSPEX) (Liu, Zhang, et al, ). An interpenetrating plasma method was adopted to isolate the generation of the inhomogeneous radial electric field and density gradient (Amatucci et al, ; DuBois, Arnold, et al, ).…”

Section: Methodsmentioning

confidence: 99%

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

Liu

Lei

et al. 2018

Geophysical Research Letters

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Laboratory observations of spontaneous emission of Alfvénic branch oscillations generated by a strong inhomogeneous plasma flow are reported in this work. Electrostatic KH instabilities in the subcyclotron frequency range were excited using the interpenetrating plasma method. Experiments indicate that spontanegeous Alfvénic branch oscillations occur when the plasma inhomogeneity increases above a threshold. The electromagnetic wave amplitude spreads out radially over a much larger extent than the electrostatic mode. Theoretical calculations using the MHD method also support the experimental observation. The result has important application in understanding the cross‐scale transport of particles and energies in astrophysical, space, and laboratory plasmas.

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Design and construction of Keda Space Plasma Experiment (KSPEX) for the investigation of the boundary layer processes of ionospheric depletions

Cited by 24 publications

References 32 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

Laboratory generation of broadband ELF waves by inhomogeneous plasma flow

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

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