The Current-Voltage Characteristics and Potential Oscillations of a Double Layer in a Triple-Plasma Device

Carpenter, R.T.; Torvén, S.

doi:10.1109/tps.1987.4316727

Cited by 12 publications

(6 citation statements)

References 14 publications

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“…For V st between 0 and about 15 V, the axial potential profile of the target chamber was relatively flat, featureless and negative with respect to earth (figure 5, curves a and b). Space potential measurements indicated the presence of negative sheath regions at both the 'cathode' (g 2 ) and the 'anode' formed by the chamber wall and g 3 (a form similar to that noted by, for example, Carpenter and Torvén [19] or Braithwaite and Allen [20]). Electrons originating in the source chamber encounter the g 2 sheath as a potential barrier retarding or rejecting any source electrons able to penetrate the g 1 sheath after they have been accelerated by V g .…”

Section: The Initial Phasesupporting

confidence: 63%

“…The high-potential plasma field region was negative with respect to earth although the variation in the electric field over the remaining part of the chamber which could be monitored appeared small. It was assumed that the potential variation over the remaining chamber length was continuous and took the form of a negative sheath as in [19] and [20].…”

Section: The Transitionmentioning

confidence: 99%

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Space charge layers in a double plasma machine

Hassall

Allen

1997

J. Phys. D: Appl. Phys.

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Experimental and numerical studies on the behaviour of space charge layers (SPLs) and related sheath-like phenomena generated in a double plasma machine (DPM) are reported. A detailed evaluation of the performance of the multidipole source used in this device indicated that, under the conditions best suited for the investigation of these structures, the emitted electron species used to form the sheath structures could contain significant quantities of electrons with a temperature approximately twice that normally assumed for such plasma sources. It is also suggested that a trapped ion population on the low-potential side of the layer region could cause inflection-like distortions as observed in the sheath potential profiles reported here and in the literature. This hypothesis was investigated using a simple one-dimensional Vlasov - Poisson kinetic model and it was found that such anomalies could also be generated with the trapped ion population absent if a high-temperature electron population was present in the plasma on the high-potential side of the layers.

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Section: The Initial Phasesupporting

confidence: 63%

Section: The Transitionmentioning

confidence: 99%

Space charge layers in a double plasma machine

Hassall

Allen

1997

J. Phys. D: Appl. Phys.

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“…The negative differential resistance shown in the current-voltage characteristic may in general lead to excitation of relaxation oscillations at a frequency close to the resonance frequency of the current circuit (e.g. Carpenter and Torven 1986). This frequency is of the order of 1 MHz or larger in the present experiment because it is determined only by the stray inductance and the stray capacitance.…”

Section: (A) When the Anode Voltagementioning

confidence: 99%

“…In contrast to the case of uniform field (Andersson 1981) the characteristics obtained here have a region of negative differential resistance which is reproduced by the characteristics calculated. Electron-reflecting potential minima have also been discussed recently in connection with current limitation in a triple plasma device in a uniform magnetic field (Lindberg and TorvCn 1983, TorvCn et a1 1985, Carpenter and Torven 1986.…”

Section: Introductionmentioning

confidence: 99%

Current limitation and formation of plasma double layers in a non-uniform magnetic field

Plamondon

Teichmann

Torvén

1988

J. Phys. D: Appl. Phys.

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Formation of strong double layers has been observed experimentally in a magnetised plasma column maintained by a plasma source. The magnetic field is approximately axially homogeneous except in a region at the anode where the electric current flows into a converging magnetic field. For field strengths larger than about 200 G the double layer has a stationary position only in the region of non-uniform magnetic field or at the aperture separating the source and the plasma column. It is characterised by a negative differential resistance in the current-voltage characteristic of the device. The parameter space, where the double layer exists, has been studied as well as the corresponding potential profiles and fluctuation spectra. The electric current and the axial electric field are oppositely directed between the plasma source and a potential minimum which is formed in the region of inhomogeneous magnetic field. Electron reflection by the resulting potential barrier is found to explain the essential features of the current-voltage characteristics observed, but further investigations of waves and fluctuations are required to clarify the current transport.

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“…The triple plasma machine maintaining a plasma column of 3 cm diameter and 60 cm length ( Fig. 1) is described elsewhere [1]. When a steady voltage drop U, exceeding k B T e /e ≈ 8 V is applied between the source chamber walls, a strong electric double layer forms in the central chamber, near aperture A 1 .…”

mentioning

confidence: 99%

Amplitude collapse of nonlinear double-layer oscillations

Wendt¹,

Axnäs²,

Torvén³

1998

Phys. Rev. E

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The negative differential resistance of a strong electric double layer in connection with an external inductive current circuit can give rise to large, self excited oscillations [1]. Here an experimental investigations of these oscillations at low oscillation frequencies and weak nonlinearity is presented. The oscillation exists only in a finite interval of dc double layer voltages, closely connected to the interval of negative damping. The amplitude characteristics show a transition from continuous profiles, similar to that of the classical van der Pol oscillator, to characteristics containing a hysteresis. Their shape and the appearance of the hysteresis phenomenon can quantitatively be explained from asymptotic solutions of the circuit equation, which is a generalized van der Pol equation with a small nonlinear damping term. The material presented here has been published in Ref. [2].

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The Current-Voltage Characteristics and Potential Oscillations of a Double Layer in a Triple-Plasma Device

Cited by 12 publications

References 14 publications

Space charge layers in a double plasma machine

Space charge layers in a double plasma machine

Current limitation and formation of plasma double layers in a non-uniform magnetic field

Amplitude collapse of nonlinear double-layer oscillations

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