Experimental Visualization of Distributed Magnetic Fields of Railguns

Electromagnetic launch produces distributed magnetic fields during firing. Data collection and visualization of this field provide a useful diagnostic tool to better understand electromagnetic launcher operation. This paper outlines an effort to visualize these fields during firing. The diagnostic tool is based on a ferrofluid that becomes strongly polarized in the presence of a magnetic field. A commercial off-the-shelf flexible film, incorporating microencapsulated ferrofluid, was draped along the top of a railgun during operation. High-speed video capture of launch provided proof of principle that the dynamics of magnetic field formation could be recorded. Conformal mapping of the video provided quantitative contours for validation of numerical models.