On grid launched linear and nonlinear ion-acoustic waves. III

Raychaudhuri, Santwana; Gabl, E. F.; Tsikis, Eugene K.; Lonngren, Karl E.

doi:10.1088/0741-3335/26/12b/001

Cited by 9 publications

(5 citation statements)

References 13 publications

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“…Previous experiments on ion-wave excitation were often conducted in Q-machine or double-plasma devices (DPDs), mostly in DPDs. One way to launch the ion waves was to apply an excitation voltage to a grid (called excitation grid), [21][22][23] and the excited wave signals were detected by a movable electrostatic probe. In experiments, using a pulse (or pulsed train of sinusoidal signal) as the excitation voltage, a kind of pseudowave signal was detected to coexist and be in front of the excited ion-acoustic wave.…”

Section: Introductionmentioning

confidence: 99%

“…In experiments, using a pulse (or pulsed train of sinusoidal signal) as the excitation voltage, a kind of pseudowave signal was detected to coexist and be in front of the excited ion-acoustic wave. [24] This signal, whose characteristics are totally different from those of the normal modes, was recognized as a burst-ion signal, [21][22][23][24][25] because it was believed that this signal is from the ions bursting out of the sheath of the excitation grid when the grid voltage is suddenly raised (by the applied pulse), i.e., it is the signal of the burst ions directly collected by the probe rather than that of the collective waves. This pseudowave is important because its velocity can be controlled by the applied excitation voltage and, thus, the wave-particle interaction between the ionacoustic wave and the burst ions can be studied via observing the evolution of the excited signals.…”

Section: Introductionmentioning

confidence: 99%

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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%

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 pseudowave signal appears only when launching the ion-acoustic wave with the partially transparent excitation grid (not nontransparent plate) and was attributed to the ions bursting out of the sheaths of the excitation grid when the sheath potential was rapidly raised because of the application of the excitation voltage. [21][22][23] It was also known as the burst-ion signal consisting of a pulsed ion beam released from the sheaths of the grid. [20][21][22][23] The signal velocity of the pseudowave (or burst-ions) depends sensitively on the characteristics of the excitation voltage (boundary condition), [21,24] which is totally different from the normal mode whose velocity is determined by the dispersion relation.…”

Section: Introductionmentioning

confidence: 99%

“…[21][22][23] It was also known as the burst-ion signal consisting of a pulsed ion beam released from the sheaths of the grid. [20][21][22][23] The signal velocity of the pseudowave (or burst-ions) depends sensitively on the characteristics of the excitation voltage (boundary condition), [21,24] which is totally different from the normal mode whose velocity is determined by the dispersion relation. By controlling the excitation voltage, the burst-ion velocity can be adjusted close to the velocity of the ion-acoustic wave.…”

Section: Introductionmentioning

confidence: 99%

Observation of double pseudowaves in an ion–beam–plasma system

Wei¹,

Ma²,

2018

Chinese Phys. B

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Pseudowaves, known as burst-ion signals, which are different from plasma normal modes, exist frequently in ionwave excitation experiments when launching the waves by applying a pulsed voltage to a negatively biased grid. In previous experiments, only one kind of the pseudowave was observed. In this paper, we report the observation and identification of double pseudowaves in an ion-beam-plasma system. These pseudowaves originate from two ion groups: the burst of the beam ions and the burst of the background ions. It was observed that the burst of the background ions was in the case of high ion beam energy, while the burst of the beam ions was in the case of low ion beam energy. By observing the dependence of the signal velocities on the characteristics of the excitation voltage, these pseudowaves can be identified. It was also observed that the burst ion signal originating from the background ions can interact with slow beam mode and that originating from the beam ions can interact with fast beam mode.

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“…These ion bursts are also called pseudo-waves [29]. The properties of these ion bursts depend on the excitation signal [5,6,30,31]. Strong interaction of these fast ions with the solitons has also been investigated [32,33].…”

Section: Introductionmentioning

confidence: 99%

Experimental and simulation studies on soliton generation in a double-plasma device: role of fast ions

Aziz¹,

Malik²,

Enge³

et al. 2011

Plasma Phys. Control. Fusion

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Soliton generation mechanism in a double-plasma device is explored by carrying out diagnostics measurements using a Langmuir probe and laser induced fluorescence. Soliton profiles are investigated for different amplitudes, durations and frequencies of the applied grid signal. Particle-in-cell simulations are also carried out in order to study in detail the evolution and propagation mechanism of solitons. For low temperature ions, the simulation results show similar features as observed in the experiment. However, the simulations with fast ions having larger velocities than the soliton show strong interaction of the fast ions with the soliton and ion burst, producing another soliton through the energy exchange mechanism.

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On grid launched linear and nonlinear ion-acoustic waves. III

Abstract: This paper extends our study on grid excited ion-acoustic solitons to examine far field radiation characteristics. In particular, for propagation distances greater than any launching grid dimension, the solitons propagate as spherically expanding shells.

Cited by 9 publications

References 13 publications

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

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

Observation of double pseudowaves in an ion–beam–plasma system

Experimental and simulation studies on soliton generation in a double-plasma device: role of fast ions

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