Topic
Q-machine
About: Q-machine is a research topic. Over the lifetime, 105 publications have been published within this topic receiving 1748 citations.
Papers published on a yearly basis
Papers
TL;DR: In this article, the Q machine was used to generate a linear, highly ionized, low temperature cesium plasma by having the output of atomic beam ovens impinge on hot tungsten plates placed at both ends of a cylindrical vacuum chamber.
Abstract: A device for generating a linear, highly ionized, low temperature cesium plasma is described. The plasma is generated by having the output of cesium atomic beam ovens impinge on hot tungsten plates placed at both ends of a cylindrical vacuum chamber. The walls of the chamber are cooled so that neutral cesium condenses on them. The theory of the device, designated as the Q machine, is presented and some experimental results given. The maximum density achieved was 2×1012/cm3, with an estimated fractional ionization of 99%, and a confining field of 5900 gauss.
205 citations
TL;DR: In this article, the effect of negatively charged dust on ion acoustic shock formation in a Q machine was investigated and it was shown that ion acoustic compressional pulses were observed to steepen as they traveled through a dusty plasma if the percentage of the negative charge in the plasma on the dust grains was ≳75%.
Abstract: An experimental investigation of the effect of negatively charged dust on ion acoustic shock formation in a Q machine is described. Ion acoustic compressional pulses were observed to steepen as they traveled through a dusty plasma if the percentage of the negative charge in the plasma on the dust grains was ≳75%.
199 citations
TL;DR: The present day version of a source of low temperature, fully ionized, quiescent plasma, known as the Q•1 device, is described in this paper, where a simplified form of the theory is presented and is extended to include absorption at the walls.
Abstract: The present day version of a source of low temperature, fully ionized, quiescent plasma, known as the Q‐1 device, is described. A simplified form of the theory is presented and is extended to include absorption at the walls. The many modifications and improvements that have been made since the device was first built are described.
115 citations
TL;DR: In this paper, the effects of transverse velocity shear on the stability of a low-frequency resistive plasma in a uniform magnetic field were examined theoretically and both numerical and analytic methods were used to identify the Q machine edge oscillation, which is identified either as a Kelvin-Helmholtz instability or as a velocity-shear analog of the resistive drift wave, depending on the parallel wavelength.
Abstract: The effects of transverse velocity shear on the low‐frequency stability of a plasma are examined theoretically for a low‐β resistive plasma in a uniform magnetic field. Cylindrical geometry is used and the velocity shear is introduced by a nonuniform E × B rotation. Both numerical and analytic methods are used. The principal analytic result is a dispersion relation for instabilities caused by a thin velocity shear layer. This dispersion relation describes the Q machine edge oscillation, which is identified either as a Kelvin‐Helmholtz instability or as a velocity‐shear analog of the resistive drift wave, depending on the parallel wavelength. The numerical results show that properties of instabilities observed in several experiments agree reasonably well with theory. The effect of velocity shear on the drift instability is to make it into either a local or nonlocal type of normal mode.
82 citations
TL;DR: In this article, double layer dynamics are investigated in a Q-machine plasma by applying a positive step potential to a cold end-plate collector, where the double layer created at the grounded plasma source just after the pulse is applied propagates towards the collector with the plasma flow speed.
Abstract: Investigations of double layer dynamics are performed in a Q-machine plasma by applying a positive step potential to a cold end-plate collector. The double layer created at the grounded plasma source just after the pulse is applied propagates towards the collector with the plasma flow speed. Large oscillations occur in the plasma current which is related to a recurring formation and propagation of the double layer. The current is limited during the propagation by a growing negative potential dip formed on the low-potential tail. Similar phenomena appear on the low-potential tail of the stationary double layer formed by applying a potential difference between two plasma sources.
70 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2013 | 2 |
| 2012 | 1 |
| 2011 | 2 |
| 2008 | 1 |
| 2006 | 4 |
| 2005 | 4 |