Bestimmung von Transportfunktionen aus den Charakteristiken zylindrischer Bögen (Wasserstoff)

Abstract

On a stationary and cylindersymmetrical arc produced in a cascade arc chamber measurements are performed in order to determine the transport coefficients of the H₂-plasma especially the electrical conductivityσ and the heat flux potential$S(S = \int\limits_{T_0 }^T {\kappa dT'}$ T=temperature,κ=thermal conductivity). In a channel of 2 mm diam. and at a pressure of 1 atm. a wall-load of 19 kW/cm² and an almost complete ionization were reached. TheE-I-characteristic was measured for H₂ in a wide range of arc currents. Because of technical and physical difficulties the totalE-I-characteristic had to be composed of measurements taken from three different channel diameters and converted by scaling laws to the smallest diameter. After this reduction an effective current range from 5·10⁻² A to 150 A is covered. For the measurement of the characteristics a quasistatic method was developed which is more precise than others used before. From the measuredE-I-characteristic the radial distributions of the transport coefficients with the arc currentI as parameter were computed exactly by means of the energy balance equation using a newly developed iteration procedure. The final result is theσ(S)-function of hydrogen.