Two-temperature Approximation Research Articles

Standing waves of gaseous chemical reactions in inert porous media

Standing waves of gaseous, exothermic, chemical reactions in inert porous media are investigated in the two-temperature and one-temperature approximations. A “semiinfinite” reaction zone method is developed to solve the problem analytically. It is shown that the wave solutions obtained by this method form a large set. Traditional solutions with strong heat transfer at the end of the wave make up but a small fraction of this set.

Laser plasma formation in metals vapour : kinetic approach

The break-down of metals vapour (Al, Cu) are simulated near the break-down threshold values of laser radiation. The approximations of collislon-radiation model are used, including the detail kinetics of exited states with radiation and collision transitions, step-by-step ionisation process, unexitation and recombination. Energy balance is based on two-temperature approximation: for electrons and for heavy particles. It is shown that the particles concentration in exited states and plasma species composition differ rather from Saha-Boltzmann's distribution. Strong dependence of the break-down threshold intensity on initial temperature of neutral and charged particles is shown

Testing two-temperature thermal-conduction theory for carbon rod composites

Measurements have been used to test software for calculating the temperature pattern in a reinforced medium in the two-temperature approximation and for determining model parameters.

Evaluation of the electron energy distribution in a low-pressure Hg-Ar discharge with a two-temperature approximation

The low-pressure mercury-argon discharge was analyzed employing a two-temperature representation of the electron energy distribution. The electron energy distribution function was approximated with two Maxwellian portions, which represented a low-energy part of the electrons (bulk) characterized by higher temperature and a high-energy part of the electrons (tail) characterized by lower temperature. As a parameter representing non-Maxwellian distribution, the ratio of the tail temperature to the bulk temperature was introduced. The ratio was determined experimentally by adjusting the calculated field strength of the positive column to the observed one. The plasma parameters under the two-temperature approximation were shown to be obtainable by solving the rate equations for the particle densities and the energy balance equation for the whole electron group. The model was applied to the positive column of a 24-mm-diam tube. The rate coefficient of Hg 61S0 to Hg 61P1 transition was found to be 0.64 times that obtained under the Maxwell approximation.

Plasma formation due to interaction of a CO2laser pulse with an aluminum target

A theoretical model is developed for the formation of a plasma due to the interaction of CO2 laser pulses with an aluminum target in air. This model allows for the heating and evaporation of the target and for the absorption of the laser radiation in the moving vapor whose state is described in the two-temperature approximation. Use is made of the experimental shapes of the laser radiation pulses of 1–400 MW/cm2 intensity and 0.01–10 μ sec duration. The calculated plasma-formation times are in agreement with the experimental data, especially when allowance is made for the possibility of existence of thermally insulated microregions on the irradiated target surface.

Solution of the self-similar problem of the outflow of a gas into a vacuum in the two-temperature hydrodynamic approximation

THE PLANE one-dimensional problem of the expansion into a vacuum of the gas formed as the result of the interaction of radiation with matter is investigated. The gas is regarded as completely ionised and is studied in the two-temperature hydrodynamic approximation taking into account the electronic heat conduction and energy exchange between ions and electrons. A qualitative analysis and self-similar solutions are constructed by a numerical method for the case of an infinitely large absorption coefficient. The properties of various modes of propagation of heat in the moving medium are studied.

Self-similar solution of the Navier-Stokes equations for a completely ionized hydrogen plasma (the plane piston problem)

The self-similar motion of a completely ionized hydrogen plasma is considered in the two-temperature hydrodynamic approximation, i.e., we consider the plane piston problem and the problem on energy release at a fixed wall. Results obtained by numerical integration of the relevant system of ordinary differential equations are quoted.