Hypervelocity dust beam injection for national spherical torus experiment

An internal magnetic field measurement technique using hypervelocity dust beam injection is described for eventual implementation on the National Spherical Torus experiment. The principle of the diagnostic has been described previously [Wang and Wurden, Rev. Sci. Instrum. 74, 1887 (2003)]. Approximately 200 kV of electrostatic potential will be used to accelerate multiple dust particles to velocities in the range of 1.0–10 km/s. A fast framing camera will be used to visualize and map two-dimensional internal magnetic field structure from the orientation of the visible light emissions generated by the plumes associated with the hypervelocity dust.