Performance of the university of saskatchewan compact torus injector with curved acceleration electrodes

The first vertical compact torus (CT) injection experiment has been performed in the Saskatchewan Torus Modified (STOR-M) tokamak [Nucl. Fusion 46, 104 (2006)]. To increase the kinetic energy density of the injected CTs for deeper penetration, the University of Saskatchewan Compact Torus Injector (USCTI) was further modified by attaching a 90° curved inner electrode coaxial with the outer electrode. The modification extended the original CT acceleration section from 60to114cm. Effects of the curved acceleration electrodes on the velocity and magnetic field of the CT are reported in this paper. It has been found that the CTs, injected horizontally, were deflected to vertical direction and CT velocity measured at the curved acceleration section increased to 180km/s, representing a 40% increase compared with the case without the curved inner electrode in a previous experiment. At a higher acceleration bank voltage of 16kV, this velocity increased to about 270km/s. In addition, amplification of the CT magnetic field in the curved acceleration section has also been observed.