Abstract
A low-inductance, multichannel railgap has been used to switch a low-inductance capacitor bank driving, for example, a dense plasma focus. To generate multichannel arcs, a fast rising trigger voltage, greater than 5kV/ns, is necessary (Neil's condition).
In order to obtain a high-voltage and short rise time pulse, a sharpener is indispensable. A self-breakdown gap is generally used for this, but it is not reliable. We therefore investigated the charactaristics of a ferrite sharpener, which is much more reliable. We achieved the following results.
(1) We obtained detailed data on relation of output rise time to source voltage, bias current, and line length. (2) We found that the ferrite sharpener is superior to the sharpener gap in reliability of operation. (3) At a source voltage of 14kV, the rise time of the ferrite sharpener attained the speed of 5kV/ns.
