Measurement of the flow velocity in unmagnetized plasmas by counter propagating ion-acoustic waves

X., J.; Li, Yang‐Fang; Xiao, Di; Li, Jing-ju; Li, Yiren

doi:10.1063/1.1924651

Cited by 16 publications

(9 citation statements)

References 19 publications

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“…[5] In a drifting plasma with flow velocity much lower than the ion-acoustic speed, the ion-acoustic waves propagating against the flow were investigated in a few experiments. [19,20] However, in the ion-beam-plasma systems, the experimental studies of the excitation and propagation of ion waves in the upstream direction have not been reported.…”

Section: Introductionmentioning

confidence: 99%

Upstream ion wave excitation in an ion-beam–plasma system

Wei

et al. 2018

Chinese Phys. B

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Plasma normal modes in ion-beam-plasma systems were experimentally investigated previously only for the waves propagating in the downstream (along the beam) direction. In this paper, the ion wave excitation and propagation in the upstream (against the beam) direction in an ion-beam-plasma system were experimentally studied in a double plasma device. The waves were launched by applying a ramp voltage to a negatively biased excitation grid. Two kinds of wave signals were detected, one is a particle signal composed of burst ions and the other is an ion-acoustic signal arising from the background plasma. These signals were identified by the dependence of the signal velocities on the characteristics of the ramp voltage. The velocity of the burst ion signal increases with the decrease of the rise time and the increase of the peak-to-peak amplitude of the applied ramp voltage while that of the ion-acoustic signal is independent of these parameters. By adjusting these parameters such that the burst ion velocity approaches to the ion-acoustic velocity, the wave-particle interaction can be observed.

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Section: Introductionmentioning

confidence: 99%

Upstream ion wave excitation in an ion-beam–plasma system

Wei

et al. 2018

Chinese Phys. B

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“…The experiment was conducted in a modified double-plasma device, [43] which consists of two identical grounded chambers each 500 mm long and 500 mm in diameter, as schematically shown in Fig. 1.…”

Section: Experimental Arrangementmentioning

confidence: 99%

“…Since the ion collisions are mainly due to the charge-exchange collisions with Ar atoms, the cross section σ is of the order of 6 × 10 −15 cm 2 . [43,46] Thus, the ion mean-free-path is in the range of λ i ∼ 51-213 mm. In addition, the electron Debye length in the bulk plasma is λ D ∼ 1 mm.…”

Section: Experimental Arrangementmentioning

confidence: 99%

“…The ion flow velocity (here is the diffusion velocity) was determined with the method of the phase velocities of two counter propagating ion-acoustic waves. [43] With these input parameters, equations ( 2)-( 5) were numerically solved until the ion velocity reached the Bohm speed. The typical potential drops in the presheath under three different pressures are ∆V = 1.4T e /e for p = 1.5 × 10 −1 Pa, ∆V = 1.2T e /e for p = 8 × 10 −2 Pa, and ∆V = 1.0T e /e for p = 3.6 × 10 −2 Pa, respectively.…”

Section: Presheath Potential Dropmentioning

confidence: 99%

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Experimental studies of plasma sheath near meshes of different transmissivity

Zheng

et al. 2010

Chinese Phys. B

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The measurements of the potential distributions in the boundary layer near meshes with different mesh spacing were conducted in weakly collisional plasmas using a fine-structured emissive probe and the results of the sheath thickness and electric field at the sheath-presheath edge were compared with theoretical models of collisional presheath and collisionless sheath. It was shown that, because the meshes are partially transparent to ions, the sheath is thinner and the electric field is stronger for the mesh of higher transmissivity, owing to the increased ion density in the sheath contributed from the ions transmitted from the other side of the mesh. However, the potential profiles in the presheath remain almost the same for different meshes except for the shift of the sheath-presheath edge. The thickness of the sheath decreases while the electric field at the edge increases with the increase of the neutral gas pressure. Furthermore, depending on the pressure, the measured electric fields at the edge are close to that from the models of a transition region.

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“…The experiment was conducted in a modified doubleplasma device, 28 which consists of two identical chambers each 500 mm long and 500 mm in diameter, as schematically shown in Fig. 1.…”

mentioning

confidence: 99%

Measurement of the flow velocity in unmagnetized plasmas by counter propagating ion-acoustic waves

Cited by 16 publications

References 19 publications

Upstream ion wave excitation in an ion-beam–plasma system

Upstream ion wave excitation in an ion-beam–plasma system

Experimental studies of plasma sheath near meshes of different transmissivity

Measurement of virtual cathode structures in a plasma sheath caused by secondary electrons

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