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Manuscript Title: Scalar DC electrical conductivity of partially ionized gases.
Authors: D.A. Erwin, J.A. Kunc
Program title: SIGDCS
Catalogue identifier: AALE_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 42(1986)119
Programming language: Fortran.
Computer: VAX 11-750.
Operating system: VMS 4.1.
RAM: 8K words
Word size: 32
Keywords: Conductivity, Plasma physics, Transport, Coulomb collisions, Boltzmann equation, Discharge.
Classification: 19.5, 19.11.

Nature of problem:
Calculation of the electrical conductivity of a magnetic field-free plasma, as a function of electron density and temperature and of the gas density, taking into account both electron-neutral and Coulomb collisions. This is necessary when dealing with plasmas of medium ionization degree, when neither type of collisional process may be neglected.

Solution method:
The approach of Erwin and Kunc is applied, with appropriate simplification for the dc case with zero magnetic field. This approach uses the matrix method of Shkarofsky et al., assuming the electron- neutral momentum-transfer cross section to be a power-law function of electron energy; we have used a least-squares method to approximate the actual cross section by a power law in the vicinity of the peak of the electron energy distribution function, assumed to be Maxwellian. The calculation may be performed for any gas for which the cross section is known; this program supplies cross sections for H, O, He, Ne, Ar, Xe, Kr, H2, N2, O2, NO and CO.

The approximation mentioned above will be invalid for gases and electron temperatures such that the electron-neutral cross section is non- monotonic and rapidly varying around the thermal energy. The supplied cross sections extend to 20 eV in electron energy, which gives an upper limit of 38,000 K for the electron temperature (integration is performed out to electron energy 4 kTe, where k is Boltzmann's constant and Te is the electron temperature.) Dissociation of molecular gases is not taken into account, so that this method is invalid for conditions under which these gases are significantly dissociated.

Running time:
Of order one second on the VAX 11/750.