Comparison of gridded energy analyzer and laser induced fluorescence measurements of a two-component ion distribution

Harvey, Zane; Thakur, Saikat Chakraborty; Hansen, Alex; Hardin, Robert; Przybysz, William; Scime, Earl

doi:10.1063/1.2953411

Cited by 26 publications

(51 citation statements)

References 10 publications

(14 reference statements)

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“…The RFEA consists of four closely spaced mesh screens ͑250 lines per inch nickel mesh glued to copper support rings͒ placed behind a grounded aperture and held in grounded probe assembly. 17,18 The RFEA probe and associated electronics are described in detail in Ref. 18 locations along the axis of the expansion chamber.…”

Section: Experimental Apparatusmentioning

confidence: 99%

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Time-resolved measurements of double layer evolution in expanding plasma

et al. 2010

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Observations in steady-state plasmas confirm predictions that formation of a current-free double layer in a plasma expanding into a chamber of larger diameter is accompanied by an increase in ionization upstream of the double layer. The upstream plasma density increases sharply at the same driving frequency at which a double layer appears. For driving frequencies at which no double layer appears, large electrostatic instabilities are observed. Time-resolved measurements in pulsed discharges indicate that the double layer initially forms for all driving frequencies. However, for particularly strong double layers, instabilities appear early in the discharge and the double layer collapses.

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Section: Experimental Apparatusmentioning

confidence: 99%

“…17,18 The RFEA probe and associated electronics are described in detail in Ref. 18 locations along the axis of the expansion chamber. 38 The power spectrum of the electric field fluctuations is measured with a multitip probe in the plasma source; 50 cm downstream of the rf antenna.…”

Section: Experimental Apparatusmentioning

confidence: 99%

Time-resolved measurements of double layer evolution in expanding plasma

et al. 2010

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“…The signals were high-pass filtered and amplified using amplifiers with a high bandwidth to extract fluctuations on the order of the ion plasma frequency. In all cases, the black lines show the analytical dispersion relation, whereby it should be noted that despite attempts with RFEA and Laser Induced Fluorescence [42], it was not possible to obtain an accurate measurement of the ion beam temperature. In the absence of a reliable measurement, it was assumed that the beam ions retained the same temperature as in the source, which was measured to be 0.13 eV.…”

Section: Resultsmentioning

confidence: 99%

“…The plasma was not magnetised for these experiments. The beam velocity and density were measured with a Retarding Field Energy Analyser (RFEA) [42]. Measurements of the floating potential fluctuations were taken with a pair of electrostatic probes -one stationary and one which was moved along the direction of beam propagation.…”

Section: Resultsmentioning

confidence: 99%

The effect of boundaries on the ion acoustic beam-plasma instability in experiment and simulation

et al. 2014

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The ion acoustic beam-plasma instability is known to excite strong solitary waves near the Earth's bowshock. Using a Double Plasma experiment, tightly coupled with a 1-dimensional Particle-in-Cell simulation, the results presented here show that this instability is critically sensitive to the experimental conditions. Boundary effects, which do not have any counterpart in space or in most simulations, unavoidably excite parasitic instabilities. Potential fluctuations from these instabilities lead to an increase of the beam temperature which reduces the growth rate such that non-linear effects leading to solitary waves are less likely to be observed. Furthermore, the increased temperature modifies the range of beam velocities for which an ion acoustic beam plasma instability is observed.

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“…[15][16][17][18] In the LIF IVDF measurements shown in Fig. 1, the stationary downstream ion population (left side of the figure) and the ions accelerated in the double layer (the ion beam) are indicative of a DL upstream of the measurement location.…”

Section: Introductionmentioning

confidence: 99%

Instability limits for spontaneous double layer formation

et al. 2013

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We present time-resolved measurements that demonstrate that large amplitude electrostatic instabilities appear in pulsed, expanding helicon plasmas at the same time as particularly strong double layers appear in the expansion region. A significant cross-correlation between the electrostatic fluctuations and fluctuations in the number of ions accelerated by the double layer electric field is observed. No correlation is observed between the electrostatic fluctuations and ions that have not passed through the double layer. These measurements confirm that the simultaneous appearance of the electrostatic fluctuations and the double layer is not simple coincidence. In fact, the accelerated ion population is responsible for the growth of the instability. The double layer strength, and therefore, the velocity of the accelerated ions, is limited by the appearance of the electrostatic instability. V C 2013 AIP Publishing LLC. [http://dx.

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Comparison of gridded energy analyzer and laser induced fluorescence measurements of a two-component ion distribution

Cited by 26 publications

References 10 publications

Time-resolved measurements of double layer evolution in expanding plasma

Time-resolved measurements of double layer evolution in expanding plasma

The effect of boundaries on the ion acoustic beam-plasma instability in experiment and simulation

Instability limits for spontaneous double layer formation

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