John worked on the design, installation, and analysis of the magnetic diagnostics on the HSX stellarator in order to measure the the equilibrium plasma currents present during the plasma discharge. The pressure-driven Pfirsch-Schluter current is helical in nature because of lack of toroidal curvature in the QHS magnetic spectrum, and reduced by the high effective transform (3). The net toroidal current is predominantly bootstrap-driven. The bootstrap current is modeled by PENTA, and the time and spatial evolution is modeled by a diffusion equation that includes the 3-D nature of the plasma column.
John received his PhD (link to his dissertation) in 2011 and began work at the Princeton Plasma Physics Laboratory in Princeton, NJ.