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Title: Fast flow glow discharge studies of a Rydberg gas plasma
Author: Dash, N. A.
Awarding Body: University of Wales Swansea
Current Institution: Swansea University
Date of Award: 2005
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This thesis reports novel investigations into the fundamental characteristics of direct current, fast flowing, argon glow discharge plasmas. The results presented provide further evidence for a neutral excited state plasma as opposed to the conventional free ion-electron theory that pervades glow discharge literature. Also described are the design, development and characterisation of a third generation Fast Flowing Glow Discharge (FFGD) ion source for fundamental studies. Fundamental studies involved the titration of small amounts of He, Ar, H2, CH4, SF6, NO, NO2, C4H10 and CCI4 into both a flowing plasma and the full discharge. The chemical, electrical and charge distribution properties of the plasma were monitored simultaneously over the course of reagent introduction. The results were wholly inconsistent with the processes thought to predominate in the ion-electron model of the plasma. The quenching of Rydberg states by the reagent gases was also empirically assessed. The development of the third generation ion source involved a study of the variation of the macroscopic properties of the discharge including the residence time, discharge voltage/current and sampling cone bias. Kinetic energy analysis was also performed on ions emerging from the plasma. The formation of anionic species within the plasma and discharge were investigated. No anion formation was observed unless electronegative species were introduced. In addition a number of source adaptations were designed, tested and modelled. The work in this thesis provides further evidence that the flowing glow discharge is maintained by Rydberg states in both an extended plasmas and a full discharge system. The detected ions were shown to originate from the plasma boundary by chemi-, auto- or field-ionisation. The work supports a previous hypothesis that charge transfer between highly excited Rydberg states maintains the electric current flow across the plasmas and discharge.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available