Über Näherungsmethoden zur Bestimmung der spezifischen Wärmen und des Isentropenexponenten eines thermischen Plasmas

Abstract

Neglecting radiation, excitation energies, lowering of ionization potentials and excluding the simultaneous existence of more than one ionizations one can, in the case of equilibrium, find simple expressions for the specific heats and the isentropic exponentγ _s .

$$\gamma _s \frac{p}{\rho } = \left( {\frac{{\partial p}}{{\partial \rho }}} \right)_s .$$

The ratio of specific heatsγ and the isentropic exponentγ _s are then related by a function, which only depends on the corresponding degree of ionization. The maximal difference betweenγ andγ _s decreases from 12.5 to 2.4% in the range from the 1st to the 10th ionization. Regarding the dissoziation of a diatomic molecule with excited rotational and oscillation energy, but without excitation energies of electrons, it is shown thatγ andγ _s are related by the same function, which is valid for the 1st ionization.

For Helium and Argon e.g. the calculated values only show (up to the 5th ionization) deviations of less than 5% from the known values.