The Use of Compact Toroid Injection for Tokamak Central Fuelling and Runaway Electron (re) Mitigation during Disruption Events

1 Tokamak fuelling using high velocity compact torus (CTs) Compact toroids (CTs) are self-organized magnetized plasmoids in a nearly force-free Taylor state. In the laboratory, CTs can be formed using coaxial electrodes and a solenoid magnetic field coil. The resultant CT equilibrium is sufficiently robust that it can withstand extremely large acceleration ( > 10 g) and can achieve high final velocity ( ~ 1000 km/s) in a short distance ( < 5 m) and a fast time period ( < 100 μs). The final high velocity gives the CTs the kinetic energy density to penetrate the confining magnetic field of a tokamak. In other words, the penetration condition is