We performed a theoretical and experimental study of low-frequency oscillation in a Hall thruster. The oscillation phenomenon depends on various external control parameters. However, we found that such dependence can be observed very clearly using certain expressions, which are combinations of external control parameters. Using these expressions, one can observe the oscillation strength and oscillation mode for a given set of external control parameters. We considered that low-frequency oscillation can be essentially suppressed by a method of determining parameter sets. The method of determining the parameter sets is very important for Hall thruster design and control; in particular, it makes it easy to manage electromagnetic compatibility with the other equipments in a satellite, using a power supply control.

A detailed study of radiative transfer of vacuum ultraviolet emission in a plasma display panel is presented for the first time. Extensive experimental data obtained from a front panel in a test chamber are compared with a theoretical model. The model accounts for radiation trapping and opacity broadening of resonance lines, as well as the major collisional dynamics among ions, neutrals, and electrons in a xenon/neon discharge. The model was also used to predict the panel illumination efficiency, a parameter of prime importance for display designers. The results from the model yielded good agreement with experimental results over a wide range of pressures and cell geometries.

We apply V-Q Lissajous' figure for the discharge measurements of ac PDPs (Plasma Display Panels) which have the electrodes covered with dielectric. From measuring the V-Q Lissajous' figure, we can know the wall voltage and the voltage between the discharge gap. We can also know the sparking voltage and extinction voltage. We compare the PDP discharge, which occurred at fast rise time applied voltage, and ozonizer discharge, which occurred at slow rise time applied voltage. Then we know that the discharge phenomena of PDPs, which sparking voltage is very high and extinction voltage is very small, is completely different from that of ozonizer discharge, which gap voltage is kept constant, the sustain voltage V*. From the point of view, we propose noble discharge model for ac-PDPs.

An innovative engine, designated "Volterra," has been developed and the thrust performance, thrust, beam divergence angle, and ion energy distribution function were investigated using a 1 kW class magnetic-layer-type Hall thruster developed at Kyushu University. The thrust of this engine is superior to that of the thruster with 150 V constant voltage operation, but the ion energy distribution function is wider. Plume divergence is almost the same as for the thruster with 150 V constant voltage operation.

No abstract