Gesetzmäßigkeiten von Funkenentladungen im Nanosekundenbereich

Abstract

In the experimental section of this paper it is shown how the shape of the electrical spark discharge pulse (in air) depends on the discharged capacitor C, the initial field strength E0, and the inductance of the electrodes and of the spark L0. In order to get nanosecond pulses, the time constant C must be some nanoseconds and the circuit has almost to be damped critically. The experiments confirm that this can be achieved for each capacitor C by choosing a suitable spark length l (or field strength E0). In the theoretical section the current is calculated for a discharge circuit with a time-dependent spark resistance R(t)=g/t. Under certain assumptions a solution for a “hard” discharge can be calculated according to the theory of WEIZEL and ROMPE. Thus formulae for imax, (di/dt)max, the spark resistance constant g0 and the risetime τan are obtained, and these prove to be in fair agreement with experimental results. The half-width of the light pulse exceeds that of the envelope of the electrical pulse approximately 1 ... 2 nanoseconds. Thus the design of nanosecond light sources can be based on this theory.