I study a dusty plasma produced in a DC glow discharge device. The chamber is a stainless steel cylinder 0.6 m in diameter and 0.9 m long. A stainless steel disk 3.2 cm in diameter acts as the anode and the walls act as the cathode. The discharge current is set between 1 - 10 mA and the voltage at the anode between 250 - 300 V. Dust is initially on a tray beneath the anode, and becomes trapped in the anode glow naturally with high discharge current. A secondary cloud can be made at a different location using a biased mesh. I make experimental observations of the dynamics of the secondary cloud as well as the unique interaction of the dust with a wire loop near the anode.
First, I describe the interaction of the secondary cloud with a wire when it the cloud is released to flow back to the primary cloud. A detached bow shock is observed as the cloud encounters an obstacle, and an elongated teardrop shaped void is formed downstream of the obstacle.
Second, a continuous flow is set up using at biased ring. The potentials of the ring and anode create a converging-diverging electrostatic potential structure which accelerates dust particles into a thin stream in the diverging section. The interaction of this stream and a wire obstacle is described.
Finally, the potentials of the mesh and anode are suddenly switched to float simultaneously to observe the secondary cloud expansion in the afterglow plasma. The rate of expansion is shown to depend inversely on the background pressure in the range of 100-200mTorr. The expansion shows a separation in the cloud and possible Yukawa-like expansion where the center of the cloud does not respond initially to the removal of confinement.
| Identifer | oai:union.ndltd.org:uiowa.edu/oai:ir.uiowa.edu:etd-5751 |
| Date | 01 May 2015 |
| Creators | Meyer, John Kenneth |
| Contributors | Merlino, R. L. (Robert L.), 1951- |
| Publisher | University of Iowa |
| Source Sets | University of Iowa |
| Language | English |
| Detected Language | English |
| Type | dissertation |
| Format | application/pdf |
| Source | Theses and Dissertations |
| Rights | Copyright 2015 John Kenneth Meyer |
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