# ENERGY TRANSFER PROCESSES IN A PARTIALLY IONIZED GAS. Hypersonic Research Project Memorandum No. 61

## Abstract

An analysis was made of the transport properties of a partially ionized gas subject to the constraint that the average random energy of all constituent particles is exactly equal (equipartition of energy). A set of tractable equations describing the mass and energy diffusion in a partially ionized gas was obtained that included all terms correct to the order of the square root of the ratio of the electron to atom mass compared to one. The transport coefficients were evaluated for helium and argon over the complete range of partial ionization assuming that the species particle densities are quite close to their equilibrium values. The analysis indicated that the electron and ion diffusion velocities are more closely coupled than the equations of Chapman and Cowling show. The added coupling implicitly applied the constraint of zero mass velocity to the gas locally. Because of this constraint a current in the direction of (E x B) x B occurred in addition to the direct and Hall currents. It is shown that the only part of the thermal conductivity that can be influenced by a magnetic field is that part of the energy carried by the diffusion of the charged particles. The development ofmore »

- Authors:

- Publication Date:

- Research Org.:
- California Inst. of Tech., Pasadena. Guggenheim Aeronautical Lab.

- OSTI Identifier:
- 4840118

- Report Number(s):
- NP-10741

- NSA Number:
- NSA-15-031714

- DOE Contract Number:
- DA-04-495-ORD-1960 AND 3231

- Resource Type:
- Technical Report

- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-61

- Country of Publication:
- United States

- Language:
- English

- Subject:
- PHYSICS; ARGON; CHAPMAN-ENSKOG THEORY; COMPUTERS; CONFIGURATION; DIFFUSION; ELECTRIC DISCHARGES; ELECTRODES; ELECTRONS; ENERGY; EQUATIONS; GASES; HELIUM; IONIZATION; IONS; MAGNETIC FIELDS; MASS; MEASURED VALUES; PLANNING; PLASMA; PRESSURE; TEMPERATURE; THERMAL CONDUCTIVITY; TRANSPORT THEORY; USES; VELOCITY; VISCOSITY

### Citation Formats

```
Cann, G L.
```*ENERGY TRANSFER PROCESSES IN A PARTIALLY IONIZED GAS. Hypersonic Research Project Memorandum No. 61*. United States: N. p., 1961.
Web.

```
Cann, G L.
```*ENERGY TRANSFER PROCESSES IN A PARTIALLY IONIZED GAS. Hypersonic Research Project Memorandum No. 61*. United States.

```
Cann, G L. Thu .
"ENERGY TRANSFER PROCESSES IN A PARTIALLY IONIZED GAS. Hypersonic Research Project Memorandum No. 61". United States.
```

```
@article{osti_4840118,
```

title = {ENERGY TRANSFER PROCESSES IN A PARTIALLY IONIZED GAS. Hypersonic Research Project Memorandum No. 61},

author = {Cann, G L},

abstractNote = {An analysis was made of the transport properties of a partially ionized gas subject to the constraint that the average random energy of all constituent particles is exactly equal (equipartition of energy). A set of tractable equations describing the mass and energy diffusion in a partially ionized gas was obtained that included all terms correct to the order of the square root of the ratio of the electron to atom mass compared to one. The transport coefficients were evaluated for helium and argon over the complete range of partial ionization assuming that the species particle densities are quite close to their equilibrium values. The analysis indicated that the electron and ion diffusion velocities are more closely coupled than the equations of Chapman and Cowling show. The added coupling implicitly applied the constraint of zero mass velocity to the gas locally. Because of this constraint a current in the direction of (E x B) x B occurred in addition to the direct and Hall currents. It is shown that the only part of the thermal conductivity that can be influenced by a magnetic field is that part of the energy carried by the diffusion of the charged particles. The development of a similarity solution for axially symmetric electric discharges is described. A number of parameters were obtained and discussed. The solution was evaluated for a discharge in argon gas at one atmosphere pressure in which the temperature on the axis of the discharge varied from 6,000 to 19,000 deg K. The current-voltage characteristic obtained from this solution was compared with an experimentally determined curve of H. Maecker. The mechanisms of energy transfer in arc jet devices are discussed. The relative magnitude of the amount of energy that is transferred to the gas in the various parts of the electric discharge was determined. The various possible electrode configurations are discussed in detail and compared. The design and performance of an annular electrode arc heater with a rotating arc is deecribed and discussed. A modified heater was constructed with the cathode emission occurring along the axis of the applied magnetic field. Details of the performance of this configuration are given. It is shown that the arc potential drop depends primarily on the strength of the applied magnetic field and the gas enthalpy downstream of the arc. The dependence of the arc potential drop on the arc current and the amibient pressure is shown to be weak over the ranges tested, e. g., 50 to 300 amperes for the current and 1 to 4 atmospheres for the pressure. Some heat transfer measurements taken with this equipment are presented. An evaluation was Made of the transport coefficients in a par tially ionized gas. Formulas were developed for determining the viscosity, thermal conductivity, and electric conductivity of the plasma. These coefficients were computed for argon and helium at one atmosphere pressure and over the temperature range of partial ionization. (auth)},

doi = {},

journal = {},

number = ,

volume = ,

place = {United States},

year = {1961},

month = {6}

}