Compact Toroid Injection on the Madison Symmetric Torus

Progress on the design, development, and performance of an experiment to inject a compact toroid (CT) plasma into the Madison Symmetric Torus (MST) device is presented. CTs are magnetized plasmoids and have been previously used for fueling, helicity injection, and improved confinement studies on fusion research devices. Using an injector developed for the Big Red Ball, CTs will be injected tangentially into the MST to study the plasma response and possible ion energization due to reconnection with the internal MST magnetic field. When injected into a tokamak, the CT experiences deceleration due to toroidal magnetic gradients and its dipole precesses in the tokamak field. Favourable reconnection conditions are produced when the CT dipole aligns with the magnetic field in the target plasma. During reconnection, the CT magnetic and directed kinetic energies are expected to be transformed into thermal particle energy. Changes in ion temperature in the background plasma due to CT injection will be measured with ion Doppler spectroscopy and a triple Langmuir probe. This work has included upgrades to the pulsed power system and associated control software generating the CT. Notably, vacuum relays have been installed to isolate the charging supply from the capacitor banks during CT discharge and prevent potential ground loops.