The electrical breakdown properties in nitrogen gas mixed with SF6 are analytically investigated in this article by making use of the ionization and attachment coefficients of the mixed gas. The ionization coefficients of nitrogen and SF6 gas are obtained in terms of the electron temperature Te by assuming a Maxwellian distribution of the electron energy. The attachment coefficient of SF6 gas is also obtained in terms of the gas temperature Te. An algebraic equation is obtained, relating explicitly the electron breakdown temperature Tb in terms of the SF6 mole fraction χ. It was found from this equation that the breakdown temperature Tb increases from approximately 2 to 5.3 eV as the mole fraction χ increases from zero to unity. The breakdown temperature Tb of the electrons increases very rapidly from a small value and then approaches 5.3 eV slowly as the SF6 mole fraction increases from zero to unity. This indicates that even a small mole fraction of SF6 in the gas dominates the electron behavior in the breakdown system. The breakdown electric field Eb derived is almost linearly proportional to the breakdown electron temperature Tb. The experimental data agree remarkably well with the theoretical results. Therefore, it is concluded that even a small fraction of SF6 gas dominates nitrogen in determining the breakdown field. In this context, nearly 25% of the SF6 mole fraction provides a reasonable enhancement of the breakdown field for practical applications.

The exited Xe atoms in the 1s 5 metastable state and the 1s 4 resonance state across the two sustaining electrode have been monitored in a micro-discharge cell of alternating current plasma display panels (PDPs) by laser absorption spectroscopy. In this study, it is found that the maximum excited xenon density is 5 4 10 12 cm 3 in the 1s 5 metastable state and 1 2 10 12 cm 3 in the 1s 4 resonance state for the PDP cell with gap distance of 150 m and width of 350 m under the fixed gas pressure of 350 torr and a mixture of Xe content ratio of 10% with Ne under driving frequency of 35 kHz. It is also observed that the exited Xe atom density and the plasma ion density are strongly correlated with one another in this experiment. It is noted that the plasma ion density reaches a minimum at the center of electrode gap and a maximum of 9 0 10 11 cm 3 in a region located 200 m away from this center under the filling pressure of 350 torr, which corresponds to the strongest discharge in alternating current plasma display panel (ac-PDP). When increasing PDP driving frequency from 35 kHz, 50 kHz up to 100 kHz, it is found that density of excited Xe atom in the 1s 5 metastable state increase from 6 5 10 12 cm 3 up to 1 39 10 13 cm 3Index Terms-Alternating current plasma display panel, excited Xe atom, laser absorption spectroscopy, metastable state, plasma ion density, resonance state.

When the electron beam is generated from the cathode, the electrode sheath plasma is also generated, and hence the perveance of diode is being vaned to change the diode output characteristics. In our pulsed power system "Chundoong", the perveance characteristics have been experimentally investigated, from which the sheath plasma expansion speed has been found to he an about 3 c d~s inside the diode. It is shown inside the diode that the sheath plasma expansion gives the influence on the electron beam current density.~ The Vircator microwave output has been shown to he dependent especially on A-K gap distance of which initial 4 mm in A-K gap distance' is found to he optimized for maximum power.

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