Experimental study on the underwater DC arc behaviors regulated by an external transverse magnetic field

An arc discharge in water can generate extremely high voltage, which has great potential to be used in DC fault protection. The voltage characteristic is closely related to the arc behaviors. However, due to the complexity of the gas-liquid mixed environment, the arc shape is difficult to observe directly. In this letter, an observation device is specially designed and underwater arc motion with millisecond-scale duration is clearly photographed. The corresponding relationship between the arc behaviors and the varied voltage is revealed. Additionally, the random behaviors of underwater arc are controlled stably by applying an external transverse magnetic field. The enhanced cooling mechanism and the directional arc motion characteristics are discussed. We demonstrate that fast elongation of the arc column and continuous heat exchange between phase surfaces are the keys to realizing a rapid increase of underwater arc voltage.