Spectroscopic temperature measurements for SF double-nozzle arcs

Radial temperature distributions of high-current SF6 doublenozzle arcs have been measured spectroscopically at 8 equally spaced points along a 10 ms duration sine-half-wave. A good representation of the measured radial profiles around peak-current is T(r) = T /sub O/ -a /sub n/ r /sup n/ with T /sub O/ = 21 000 K and n = 10. This empirical distribution is the basis of a theorectical model developed to calculate from integral conservation laws the arc-cross-section at z = O as a function of current. From temperature measurements at different z-positions the variation E(z) of the electrical fieldstrength within the gap of the system has been determined. Theoretically interesting spectroscopic net-emission-coefficients were evaluated for the stagnation point