Analytical estimation of magnetic field and arc velocities in a Walkie Edgar spark gap device

This paper presents an approach for the evaluation of the instantaneous transverse magnetic field (TMF) in the inter electrode space of a Walkie Edgar type spark-gap device. The method has been integrated into a time marching routine to enable studies of arc velocity variation in the device. The analysis shows that the TMF and hence the arc velocity vary over the peripheral length of the device. The peripheral component of the magnetic field (PMF) responsible for the lateral movement of the arc is found to be negligibly small. Dependence of the TMF magnitude on the physical parameters of the device have been studied. Arc velocities are found to be lower in zones immediately preceding the commutating gap which could lead to localized pitting of the electrode.<>