An overview of research on the “magnetic saw effect”

Summary form only given. The term “magnetic saw effect” was introduced in 1957 by Firth et. al. in [1] to describe an instability observed in high-field pulsed magnets. The instability produces fine, saw-like cuts in solid conductors, often followed by larger openings, which have since been termed “blow holes.” The magnetic saw effect is also been observed in high-current pulsed buswork and more recently in railguns. As instabilities go, magnetic sawing has not been the subject of much research, in part because for most applications it is possible to engineer ones way out of the problem by using larger conductors. It is only within the last 10 years that researchers have sought to better understand the causes of magnetic sawing and the conditions for which magnetic sawing occurs. This paper surveys the literature on magnetic sawing and discusses some of the outstanding research questions, such as the relative importance of melting versus fracture as a driver for magnetic sawing.