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Title: A theoretical study of ionization growth in gases in non-uniform electric fields
Author: Donne, K. E.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1980
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In this thesis, the spatial and temporal growth of ionization currents is investigated for electrode systems where the applied field is distorted, due to either the proximity of the enclosing discharge chamber, or the accumulation of space-charges in the discharge region. In charters 2 to 5, a two-dimensional model for determining the D.C. breakdown voltage of an electronegative gas in a nominally uniform field electrode system is described. For three separate experimental arrangements, the computations successfully predict the occurrence of anomalous breakdowns, which have been observed at larger gap spacings. In chapters 6 and 7, a one-dimensional model for computing the temporal growth of ionization in a helium discharge at low pressure between parallel-plane electrodes is described, and the computations predict time lags which are in excellent agreement with the experimental values of D.K. Davies et al. For one set of experimental values, the numerical model is used to compute the current growth through to the steady-state glow discharge regime. By allowing for the non-equilibrium nature of the electrons in the cathode-fall region, the computations are able to predict all the essential features of the normal glow discharge in helium. In chapter 8, a one-dimensional model for simulating Trichel pulse corona in CC2 at low pressure is described, and results are presented for a discharge in a hyperboloid cathode/plane anode electrode configuration. The computations give results that are in good agreement with experiment, and the size and duration of the first Trichel pulse is successfully predicted. In particular, the accumulation of the negative ion space-charge leading to the quenching of the Trichel pulse and the subsequent interpulse region is successfully modelled.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available