Optical diagnostics of dispersing He plasma

An experimental study has been made of the characteristics of radiation from a dispersing helium plasma. From measurements of the space-time dependence of the line intensities of the helium 2³P — n³D series we obtained the distribution of the populations of the n³D levels for n=3–10. The study has shown that over a wide range of conditions the high-lying levels (n=5–10) are in equilibrium with electrons while a substantial deviation from equilibrium is observed for levels n=3, 4. From the energy distribution of the populations of the upper levels we determined the space-time dependence of the electron temperature, which reflects the process of effective electron cooling during dispersal of the plasma. The gas temperature was estimated from the populations of helium singlet and triplet levels with n=5. The time distribution of the electron density in the plasma was found from the Stark broadening of the spectral lines.Deceased.V. D. Kuznetsov Siberian Physicotechnical Institute, Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 15–19, November, 1992.     

Translation planes of large dimension admitting nonsolvable groups

In this article, the question is considered whether there exist finite translation planes with arbitrarily small kernels admitting nonsolvable collineation groups. For any integerN, it is shown that there exist translation planes of dimension >N and orderq ³ admittingGL(2,q) as a collineation group.     

Periodic solutions of difference Runge-Kutta schemes

Translated from Matematicheskie Zametki, Vol. 49, No. 6, pp. 92–97, June, 1991.     

Simulating the Kinematic Dynamo Forced by Heteroclinic Convective Velocity Fields

We report on the integration of the kinematic dynamo problem in a spherical domain forced by velocity fields that are convective fluid flows resulting from a bifurcation analysis of the spherical Bénard problem. We derive a code based on generalized spherical harmonics that ensures a divergence-free magnetic field. We determine the growth or decay of a magnetic field in the kinematic dynamo equation for various physically relevant velocity fields which are stationary as well as time-periodic and chaotic. Velocity signals that are produced by heteroclinic cycles are used as an input to an energy-saturated kinematic dynamo equation that limits the growth of the linearly unstable modes. Preliminary calculations indicate the possibility of reversals of the magnetic field for this case of forcing. Received 8 October 1996 and accepted 28 April 1997     

Temperature and velocity measurement of a 3-D thermal flow field using thermo-sensitive liquid crystals

It is an important challenge to analyze a three-dimensional thermal flow field in engineering, science, and agriculture. For such an analysis, it is essential to measure physical quantities such as temperature and velocity over the entire thermal flow field. This paper presents a measurement system based on color image processing for temperature and velocity vector distributions in a three-dimensional thermal flow field. Flow visualization is accomplished by the use of thermo-sensitive liquid crystal tracers. An algorithm for the color-to-temperature transformation using a multi-layer feed-forward neural network is applied to three-dimensional natural convection in a rotating cylindrical cell. Two-dimensional temperature distributions in a slit plane are obtained by using the algorithm. A three-dimensional temperature distribution is consequently constructed by interpolating the two-dimensional distributions using the B-spline function. In addition, the Spatio-Temporal correlation method is applied to the natural convection to obtain a three-dimensional velocity vector distribution.     

A multimolecular condensation model and an analytical method for its solution

Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 4, pp. 122–123, July–August, 1991.