Volume Discharge Based Description of Pulsed Breakdown in Triggered Spark Gaps in Air

Summary form only given. Triggered spark gaps are widely used as a closing switch in high power pulse technology. In some application where output pulses with very short rise times are necessary, the inductance of the discharge column and the time delay of triggered spark gaps represent some of the major limitations. One improvement would be to have a configuration with a number of parallel paths or to try keeping the discharge in a more diffused mode with larger cross sections (volume discharge). In this paper, starting with continuity equations and Poisson´s equation with appropriate boundary conditions at the electrodes, the discharge development is simulated. Using the measured breakdown voltages of a 3D electrode geometry with cylindrical symmetry, the initial electron density distribution injected from the trigger mechanism of the triggered spark gap is calculated in a number of iterations in such a way that the predicted breakdown voltages match the measured ones. The results indicate that the breakdown mechanism is strongly dependent on the initial electron density injected into the gap. With the maximum density of injected electrons and their spatial distribution, the time delay of breakdown and the efficient cross section of the discharge column can be controlled.