Showing papers by "Norman S. Kopeika published in 1977"
TL;DR: In this article, a simple model of photoionization of excited atoms by UV photons from capacitor spark discharges is suggested to explain the improvement in both plasma density production and laser efficiency noticed by several investigators when the proportion of helium in high-pressure CO 2 laser mixtures is increased.
Abstract: A simple model of photoionization of excited atoms by UV photons from capacitor spark discharges is suggested to explain the improvement in both plasma density production and laser efficiency noticed by several investigators when the proportion of helium in high-pressure CO 2 laser mixtures is increased. Such improvements with increased He proportion take place both with and without seeding with low ionization potential dopants. The model is also applicable to explaining the arc suppression qualities of helium as well as the ability to ignite discharges at higher total pressures when the proportion of helium is increased. Several implications regarding future TEA laser work are suggested.
13 citations
12 citations
01 Jan 1977
TL;DR: Advantages of glow discharge lamps for real-time microwave holography and optimum design for such applications, using both the subnormal and abnormal glow, were described in this article, where internal signal amplification by the sub normal glow discharge was derived for the first time.
Abstract: Advantages of glow discharge lamps for real-time microwave holography and optimum design for such applications, using both the subnormal and abnormal glow, are described. In particular, internal signal amplification by the subnormal glow discharge is derived for the first time.
4 citations
TL;DR: In this article, a hypothesis that such phenomena are two-step processes is proposed and an experiment is suggested to study this hypothesis further. But this hypothesis is based on a two-stage process.
Abstract: Disagreement between experiment and theory involving multiphoton ionization has led to a hypothesis that such phenomena are two-step processes. An experiment is suggested to study this hypothesis further.
3 citations
TL;DR: The high response of a subnormal as compared to an abnormal glow discharge to microwave radiation is a result, of large internal amplification within the discharge composed of ionizing collisions involving signal electrons and secondary emission processes as mentioned in this paper.
Abstract: The high response of a subnormal as compared to an abnormal glow discharge to microwave radiation is a result, of large internal amplification within the discharge composed of ionizing collisions involving signal electrons and secondary emission processes Diffusion current losses in the cascade ionization process are analysed and are found to be significant in the subnormal glow Rise-time limitations indicate that the positive ion signal gain cannot be neglected Treatments involving ionization and secondary emission coefficients are amended accordingly
2 citations