Browsing by Subject "Space charge"
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Item Space-charge dominated phenomena in electrical breakdown of gases(Texas Tech University, 1984-05) Dhali, Shirshak KumarIn the pre-breakdown stage of electrical breakdown of gases under high pressure and high voltage, the space-charge field and the secondary mechanisms for electron production such as gas photoionization play an important role. The collective phenomena due to the above effects called streamers, are propagating wave-like solutions of the transport equations. Results of the application of flux corrected transport techniques to a two-dimensional numerical simulation of streamer propagation are presented. To our knowledge, this work represents the first application of this technique to the problem of space-charge dominated transport in a fully two-dimensional model. Characteristics such as diameter, velocity, shape and density gradients of the streamer head, and ionization in the body of the propagating streamer are determined, and analytic relationships between them are presented. These results provide new insight into streamer propagation.Item The effect of space charge induced by an electon beam on spark gap operation(Texas Tech University, 1981-08) Tzeng, YonhuaAn investigation into the effect of electron beam induced space charge on the insulating property of a gas in a spark gap is presented. The characteristics of the gas transition from insulator to conductor show strong dependence on the amount and location of the space charge introduced. Investigations of the delay time and the characteristics of the conducting channel have been made. The delay time from the injection of the electron beam to the collapse of the gap voltage ranges from 10^-9 to 10^-3 second. From open shutter photography, we observe that the character of the conducting channel is quite varied. Dark, diffuse, filamentary, or diffuse followed by filamentary (single or multi) channels have been observed, depending on the space charge conditions. The fundamental processes leading to the collapse of insulating property of the gas for various experimental conditions are discussed.