The Influence of the Fluctuation Amplitude on the Probe Characteristic

Klagge, S.; Maass, Martin

doi:10.1002/ctpp.19830230403

Cited by 18 publications

(12 citation statements)

References 12 publications

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“…In addition, the effect of oscillations on the probe characteristic decreases sharply when the electron energy increases. 26,28 Consequently, we are confident that our time-averaged probe measurements, especially in view on the high-energy electron beams appearing on the EEDF, are not significantly influenced by the plasma instabilities. The lowenergy part of the EEDF, however, especially that near the plasma potential (zero energy), might be affected by the fluctuations of the plasma potential in the near-field and inside the thruster, where the fluctuation amplitude is large.…”

Section: B Specificsmentioning

confidence: 70%

Electron energy distribution function in a low-power Hall thruster discharge and near-field plume

et al. 2018

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Electron temperature and plasma density, as well as the electron energy distribution function (EEDF), have been obtained inside and outside the dielectric channel of a 200 W permanent magnet Hall thruster. Measurements were carried out by means of a cylindrical Langmuir probe mounted onto a compact fast moving translation stage. The 3D particle-in cell numerical simulations complement experiments. The model accounts for the crossed electric and magnetic field configuration in a weakly collisional regime where only electrons are magnetized. Since only the electron dynamics is of interest in this study, an artificial mass of ions corresponding to m i ¼ 30 000m e was used to ensure ions could be assumed at rest. The simulation domain is located at the thruster exit plane and does not include the cathode. The measured EEDF evidences a high-energy electron population that is superimposed onto the low energy bulk population outside the channel. Inside the channel, the EEDF is close to Maxwellian. Both the experimental and numerical EEDF depart from an equilibrium distribution at the channel exit plane, a region of high magnetic field. We therefore conclude that the fast electron group found in the experiment corresponds to the electrons emitted by the external cathode that reach the thruster discharge without experiencing collision events.

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Section: B Specificsmentioning

confidence: 70%

Electron energy distribution function in a low-power Hall thruster discharge and near-field plume

et al. 2018

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“…It is well known that electrostatic probes in a plasma with sinusoidal oscillations in plasma (space) potential V s will have distorted current-voltage (I -V ) characteristics because what is measured is the dc average of a nonlinear I -V relationship [1][2][3]. This effect is shown in figure 1.…”

Section: Introductionmentioning

confidence: 99%

Langmuir probe measurements in the intense RF field of a helicon discharge

Chen

2012

Plasma Sources Sci. Technol.

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Helicon discharges have extensively been studied for over 25 years both because of their intriguing physics and because of their utility in producing high plasma densities for industrial applications. Almost all measurements so far have been made away from the antenna region in the plasma ejected into a chamber where there may be a strong magnetic field (B-field) but where the radiofrequency (RF) field is much weaker than under the antenna. Inside the source region, the RF field distorts the current-voltage (I -V ) characteristic of the probe unless it is specially designed with strong RF compensation. For this purpose, a thin probe was designed and used to show the effect of inadequate compensation on electron temperature (T e ) measurements. The subtraction of ion current from the I -V curve is essential; and, surprisingly, Langmuir's orbital motion limited theory for ion current can be used well beyond its intended regime.

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“…the electron temperature of plasma is independent on the shape of g(U) [6]. The modulation amplitude U Ã rf let calculate by 2U Ã rf = U(I 00 min ) À U(I 00 max ) from the second derivation of I rf (U) [6].…”

Section: The Calculation Methodsmentioning

confidence: 99%