Effect of parallel circuit parameters on the instability of a low-current vacuum arc

To clarify the instability phenomena of a low-current vacuum arc, we observe the phenomena by changing the parallel circuit parameters. We measure instability-initiation current, chopping current, arc voltage, reignition voltage peak, and the transient recovery voltage by using copper, copper chromium, copper tungsten, and silver tungsten carbide electrodes. We find that the chopping current, reignition voltage peak, and transient recovery voltage depend on parallel circuit parameters, but the instability-initiation current and arc voltage do not depend on them. We also find that the instability phenomena depend primarily on the cathode material.